84 results on '"Finite difference model"'
Search Results
2. Experimental validation of a numerical model for a sand-based seasonal thermal energy storage.
- Author
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Pinto, Rebecca I. and Beausoleil-Morrison, Ian
- Subjects
HEAT storage ,HOT water heating ,FINITE differences ,SPACE heaters ,HEAT transfer - Abstract
A research facility with solar thermal collector system and a water-saturated, sand-based seasonal thermal energy storage (SSTES) is used to provide space heating and domestic hot water heating to homes in cold climates. A 3D finite difference model of the heat transfer in and around the SSTES is presented and validated with measured data. The SSTES has lost moisture over time, making its thermal properties difficult to estimate. Additionally, the experimental data shows the SSTES losing heat at twice the expected rate, potentially due to incorrect thermal parameters from the manufacturer and the SSTES insulation being damaged or degraded. The final numerical model was validated over a 163-day period where energy was being injected into and extracted from the SSTES. It was found that the seasonal performance of the SSTES could be predicted by a conduction-only heat transfer model, and this model is suitable to be included in BPS tools. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Fate and Transport of Chromium Contaminant in Environment
- Author
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Raj, Abhinav, Sinha, Alok, Agarwal, Avinash Kumar, Series Editor, Sinha, Alok, editor, Singh, Swatantra P., editor, and Gupta, A. B., editor
- Published
- 2023
- Full Text
- View/download PDF
4. A finite difference method on crack resistance of reinforced glass beam with non-linear adhesive.
- Author
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ZHANG, Dejun and CHEN, Suwen
- Subjects
- *
FINITE difference method , *STRAINS & stresses (Mechanics) , *SHEAR (Mechanics) , *INTERFACIAL stresses , *FINITE differences , *ADHESIVES - Abstract
Reinforced glass beam (RG beam) is a type of structural glass member that has been developed in recent years. This RG beam consists of a glass beam to which reinforcement material, such as steel, is adhesively attached in the tensile side to improve crack resistance. The adhesive plays a critical role in the structural performance of RG beam. However, the effect of non-linear shear-slip behavior of the adhesive layer remains unclear and has been neglected in most previous studies, which can result in inaccurate estimations. To address this issue, this paper presents a finite difference model (FDM) that utilizes an explicit step-by-step method and trial-and-error iterative method for interfacial stress analysis. The model predicts the static structural response of a simply-supported RG beam that simulates the adhesive with non-linear stress-slip behavior. Furthermore, the model describes the adherend's shear deformation in elastic. The FDM results are then compared with the finite element method (FEM), adopting discrete nonlinear connectors (springs) to simulate the adhesion, and available analytical methods. Detailed parametric studies are further conducted to investigate the influences of glass strength, load pattern, reinforcement ratio and height-to-span ratio for proposing design recommendations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Estimation of Cable Tension with Unknown Parameters Using Artificial Neural Networks
- Author
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Le, Luu Xuan, Katsuchi, H., To, L. G., Zarbaf, S. E. H. A. M., Thanh, Cuong-Le, di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Bui, Tinh Quoc, editor, Cuong, Le Thanh, editor, and Khatir, Samir, editor
- Published
- 2021
- Full Text
- View/download PDF
6. Enhancing the CE-QUAL-W2 to model dissolved lead transport and transformation in dam reservoirs: a case study of Shahid Rajaei Dam reservoir, north part of Iran.
- Author
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Shoaei, Seyyed Mohammad, Arjmandi, Seyyed Asghar, and Mirbagheri, Seyed Ahmad
- Subjects
ADVECTION-diffusion equations ,RESERVOIRS ,DAMS ,SUSPENDED solids ,HEAVY metals ,BODIES of water ,WATER quality ,HAZARDS - Abstract
Investigation of heavy metal transport in water bodies such as dam reservoirs due to the environmental hazards and the transformation complexities of heavy metals from dissolved phase to particulate phase and vice versa is of particular importance. The transport process of the dissolved heavy metals such as lead (Pb) in storage dam reservoirs is significantly influenced by the water flow, and ambient parameters such as temperature, total dissolved solids (TDS), dissolved oxygen (DO), and suspended solids (SS). Due to the lack of a suitable model to simulate the heavy metal transport in dam reservoirs, in this study, the hydrodynamics and water quality model, CE-QUAL-W2, was enhanced by developing 2D laterally averaged model for simulating the dissolved phase of Pb contaminant and applied to the Shahid Rajaei Dam reservoir, Sari, Iran. The developed model can describe the advection–dispersion and transformation processes and simulate the temporal and spatial distribution of dissolved phase of Pb concentrations. A new approach was introduced to calculate different reaction coefficients used in the transformation term of the advection–diffusion equation. Comparison of the simulation results of temperature, TDS, DO, SS, and dissolved phase of Pb with the measured values from the Shahid Rajaei Dam reservoir shows a mean percentage error (MPE) of 6.8, 4.7, 11.7, 19.7, and 7.27 respectively. The results of the present study showed that the temperature was the most effective parameter on the transformation of Pb in the Shahid Rajaei Dam reservoir due to large changes of temperature in depth as about 15 °C along with small changes in other ambient parameters in several months of the year. This phenomenon can be expected in many reservoirs that are stratified in a period of the year. However, the effect of other ambient parameters such as TDS, DO, and SS should not be neglected. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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7. Uncovering Physical Structural Model Behind Finite Difference Model for Vibration Analysis of Plates
- Author
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Zhang, H., Wang, C. M., di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Ho, Johnny C.M., editor, and Kitipornchai, Sritawat, editor
- Published
- 2020
- Full Text
- View/download PDF
8. Analysing the impact of cloth fabrics on skin temperature during and after exercise using an FDM model
- Author
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Neelam Patidar and Akshara Makrariya
- Subjects
cloth ,fibers ,temperature distribution ,skin layer ,finite difference model ,exercise ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Chemical technology ,TP1-1185 - Abstract
This study presents a 1D finite difference model that examines the influence of cloth fabrics on skin temperature during and after exercise, considering the complex nature of the human body and its susceptibility to infections and viruses. The aim is to design comfortable, high-quality fabrics that minimize potential issues caused by body temperature fluctuations. The model incorporates various physical, physiological, and thermal parameters of cloth to develop protective clothing suitable for exercise. Numerical results were compared to previous studies that analyzed skin temperature without clothing to validate the model’s accuracy. The findings indicate a minimal difference in skin temperature when wearing cotton and polyester cloth, with polyester fabric demonstrating superior characteristics such as stretchability, durability, and sweat resistance. The thermal information obtained from this model can be utilized to design appropriate clothing for diverse weather conditions, ultimately enhancing the performance and comfort of athletes, military personnel, and individuals engaged in physically demanding work. Additionally, the model can aid in developing thermal stress protocols for infection treatment and provide guidelines for physical activity to promote healthy living. This research contributes to the field of materials research by offering valuable insights into the design and development of protective clothing for exercise. By understanding the impact of cloth fabrics on skin temperature, advancements can be made in creating clothing that optimizes human comfort and performance.
- Published
- 2023
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9. A finite difference model for undefined end boundary to analyse the heat transfer in dry sands.
- Author
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Mondal, Somenath, Singh, Devendra N., Tang, Anh M., and Pereira, Jean M.
- Abstract
Accurate prediction of thermal regime (i.e. the variation of soil temperature, θ, and heat flux, ϕ) to investigate the migration of thermal energy in soil mass, poses challenge to the geoenvironmental engineers while dealing with various thermo-active structures. In this context, several numerical approaches have been attempted to solve the heat transfer equation (HTE) for conduction to predict the thermal regime. However, most of them need accurate boundary condition defined and involve complicated numerical approach which is inconvenient for the practising engineers. Hence, an attempt has been made in the present study to develop a simplified, but numerically efficient, approach based on the finite difference method (FDM) to analyse one dimensional heat transfer in dry sands when the end boundary is not defined. Furthermore, a time-dependent initial boundary condition has been applied to this model to simulate similar experimental condition and results have been compared vis-à-vis those obtained from the experiment and COMSOL Multiphysics® to validate the proposed approach. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
10. Modelling transverse solute mixing across a vegetation generated shear layer.
- Author
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West, Patrick O., Wallis, Stephen G., Sonnenwald, Frederick C., Hart, James R., Stovin, Virginia R., and Guymer, Ian
- Subjects
- *
CONTINUOUS distributions , *GOODNESS-of-fit tests , *CONTINUOUS functions , *SURFACE waves (Seismic waves) , *FLUORIMETRY - Abstract
Transverse solute mixing across a vegetation generated horizontal shear layer was quantified using laser induced fluorometry techniques for artificial and real vegetation. A two-dimensional finite difference model (FDM) was developed to describe transverse concentration profiles for flows containing transverse variations in velocity and transverse dispersion, from a steady solute input. The FDM was employed inversely, to optimize the parameters describing the transverse distribution of the transverse dispersion coefficient for vegetation generated shear layers. When laboratory data are available, continuous function descriptions produce slightly improved FDM modelled solute concentration profiles compared with simplified step discontinuity velocity and dispersion inputs. When laboratory data are not available, estimates of step or continuous transverse distributions from other work enable concentration profiles to be predicted with a similar goodness of fit. This paper presents a validated, simple, robust finite difference model to describe the mixing of solutes in a channel containing marginal vegetation. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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11. Semi-empirical mapping method for energy recovery wheel performance simulation.
- Author
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Hung, Yu-Wei and Travis Horton, W.
- Subjects
- *
COMMERCIAL buildings , *FINITE difference method , *INDOOR air quality , *FINITE differences , *ENERGY development , *INDEPENDENT sets - Abstract
• Training data sets are generated by a validated finite difference method model. • Mapping method predictions agree well with data sets from independent sources. • The new method predicts performance of wheels with different physical geometries. • The new approach method requires fewer training data points than current models. Energy recovery ventilators are often employed in buildings to decrease the energy consumed by their HVAC systems, and to improve overall indoor air quality. Several studies in the open literature have developed physical or empirical models to simulate the performance of energy recovery wheels. However, these models are often computationally intensive, time-consuming, or require numerous experimental data points to train and execute the performance predictions. These models also tend to lack flexibility for varying all of the available wheel design parameters. Hence, developing a mapping method with better computational efficiency and flexibility is the goal of this research. A finite difference numerical model for simulating the performance of an energy wheel has been developed and validated using experimental test results from independent laboratories. This model was then employed to provide an extensive data set for the development of an energy wheel performance mapping method. After validating this new mapping approach, the method predictions were compared against independent data sets from two different laboratories, and additional sources available in the literature, to identify its universality. The mapping method delivers good agreement between the predictions and validation data, and requires only a small number of data points to train, which is one of its novel contributions. Another unique contribution of the proposed mapping method is that once the model is trained it can predict the performance characteristics for other wheels with different physical design geometries and operating conditions, provided only that the desiccant material is the same. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
12. A Study on the Heat Transfer of Surrounding Rock-Supporting Structures in High-Geothermal Tunnels.
- Author
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Wang, Mingnian, Hu, Yunpeng, Liu, Dagang, Jiang, Cheng, Wang, Qiling, and Wang, Yicheng
- Subjects
TUNNELS ,HEAT transfer ,TUNNEL design & construction ,TEMPERATURE distribution ,FINITE differences ,ROCK bursts ,ROCK deformation ,CONCRETE curing ,EXPERIMENTAL design - Abstract
The temperature distribution is one of the most vital parameters which should be fully considered in high geothermal tunnel design. For the purpose of studying the impact of temperature disturbance caused by construction on temperature distribution of surrounding rock and lining structure in a high geothermal tunnel, a new finite difference model for temperature prediction was proposed. Based on the abundant field test results, forecast analysis for the research of a high geothermal tunnel in this paper is made. The results indicate that the temperature of the surrounding rock near the tunnel sidewall decreases obviously in the first 14 days while that of the surrounding rock far away is stable after tunnel excavation, and the rock temperature showed three ways of change: undulate type (<2 m), decline type (2–5 m) and stable type (>5 m). There is a linear relationship between the initial rock temperature and the released heat of the surrounding rock. The radius of the heat-adjusting layer and the initial rock temperature presents a quadratic function relation. The lining concrete actually cures under the variable high-temperature environment and the real curing temperature decreases with time and becomes stable seven days later. The results would contribute to providing support for high geothermal tunnel research and design. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
13. 深部倾斜盐岩地层套管应力及变形研究.
- Author
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韩伟民, 闫怡飞, and 闫相祯
- Abstract
Copyright of China Petroleum Machinery is the property of China Petroleum Machinery Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2019
- Full Text
- View/download PDF
14. Finite difference model of wave motion for structural health monitoring of single lap joints.
- Author
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Carrino, Stefano, Nicassio, Francesco, Scarselli, Gennaro, and Vitolo, Raffaele
- Subjects
- *
LAP joints , *THEORY of wave motion , *FINITE difference method , *STRUCTURAL health monitoring , *COMPUTER simulation - Abstract
Abstract This study is focused on the development of a finite difference model to simulate Lamb wave propagation through Single Lap Joints (SLJs). The main advantage of this model is the mathematical ability to easily reproduce the presence of a damage (debonding) as a discontinuity in velocity values. This makes our model suitable for continuous and embedded Structural Health Monitoring (SHM) of a complex structure. Numerical simulations and experimental campaigns are presented in order to validate the proposed model. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
15. A Study on the Heat Transfer of Surrounding Rock-Supporting Structures in High-Geothermal Tunnels
- Author
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Mingnian Wang, Yunpeng Hu, Dagang Liu, Cheng Jiang, Qiling Wang, and Yicheng Wang
- Subjects
high geothermal tunnel ,temperature test ,finite difference model ,variable temperature ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The temperature distribution is one of the most vital parameters which should be fully considered in high geothermal tunnel design. For the purpose of studying the impact of temperature disturbance caused by construction on temperature distribution of surrounding rock and lining structure in a high geothermal tunnel, a new finite difference model for temperature prediction was proposed. Based on the abundant field test results, forecast analysis for the research of a high geothermal tunnel in this paper is made. The results indicate that the temperature of the surrounding rock near the tunnel sidewall decreases obviously in the first 14 days while that of the surrounding rock far away is stable after tunnel excavation, and the rock temperature showed three ways of change: undulate type (5 m). There is a linear relationship between the initial rock temperature and the released heat of the surrounding rock. The radius of the heat-adjusting layer and the initial rock temperature presents a quadratic function relation. The lining concrete actually cures under the variable high-temperature environment and the real curing temperature decreases with time and becomes stable seven days later. The results would contribute to providing support for high geothermal tunnel research and design.
- Published
- 2020
- Full Text
- View/download PDF
16. A coupled finite difference mooring dynamics model for floating offshore wind turbine analysis.
- Author
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Chen, Lin, Basu, Biswajit, and Nielsen, Søren R.K.
- Subjects
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MOORING of ships , *WIND turbines , *OFFSHORE wind power plants , *MECHANICAL loads , *COMPUTER simulation - Abstract
This study develops a coupled nonlinear hydrodynamic model of a mooring system consisting of multiple cables for analyses of floating offshore wind turbines (FOWTs). The model is based on a finite difference model of submerged cables which considers cable-seabed interaction, current effect, cable bending and torsional stiffness. The implementation of the model proposes a parallelization scheme for solving the cable responses to improve the computational efficiency. The developed program is then coupled with a spar type FOWT and verified using an experimentally validated open source mooring simulation program. Furthermore, the model is used to study the impact of nonlinear dynamics of the mooring system on FOWT responses in the presence of current. Both static responses of a spar FOWT under current load and dynamic responses of the spar FOWT under wind, wave and current loads are investigated. Responses are compared where varied mooring models are used including the linear model, quasi-static model and nonlinear mooring models without and with current effect on cables considered. The results show that the current effect on cables can have a considerable impact on the restoring effect of the mooring system and hence the spar and cable responses. The current effect on mooring cables needs to be properly considered in the FOWT analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
17. The kinetics of nickel recovery from ferrous containing solutions using an Iminodiacetic acid ion exchange resin.
- Author
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Abbasi, Parisa, McKevitt, Bethan, and Dreisinger, David B.
- Subjects
- *
NICKEL , *IRON alloys , *ION exchange resins , *CHEMICAL kinetics , *SOLUTION (Chemistry) , *FINITE difference method - Abstract
This paper reports on the investigation of the loading rate of nickel onto an iminodiacetic acid ion exchange resin (TP207XL) under the finite solution volume condition in the presence of ferrous in a batch loading system. A hybrid correlation model (McKevitt, 2012) was applied for nickel-ferrous displacement loading data. The experimental fit parameters of the hybrid correlation were used to successfully predict the results of the batch loading experiments by applying the finite difference model. The finite difference model was applied to predict the loading behavior of nickel in the presence of ferrous in the batch system using the modified Helfferich number and the linear isotherm equation. As confirmed, the ion exchange reaction examined in this study was predominantly controlled under some combination of intraparticle diffusion/ion exchange reaction. Regarding the hybrid correlation fit parameters (D app = 9.95 × 10 − 12 m 2 /s, α = 0.65), these parameters correlated well with the loading behavior of nickel onto resin. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
18. Modelling the thermal conductivity of a melting snow layer on a heated pavement.
- Author
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Nuijten, Anne D.W. and Høyland, Knut V.
- Subjects
- *
THERMAL conductivity , *SNOWMELT , *PAVEMENTS , *FINITE difference method , *COMPRESSED water , *MATHEMATICAL models - Abstract
A snow layer on a heated pavement strongly affects the energy balance at the pavement surface. Freshly fallen snow has a fairly low thermal conductivity and acts as a good insulator. The thermal properties can vary greatly during the melting process. This study looks into the change of the thermal conductivity during the melting process of dry uncompressed and compressed snow on heated pavements. The energy balance of the heated pavement system is described and the effective thermal conductivity of the melting snow layer during the melting process of snow on a heated pavement system is calculated based on the volume fractions and thermal conductivity of ice, water and air. The results show that the thermal conductivity of an uncompressed and compressed melting snow layer on a heated pavement can be best described as a combination of a parallel and series system. Ice and air are modelled as a series system and water and ice/air are modelled in parallel. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
19. 飞秒激光加工 K24 高温合金的仿真与试验分析.
- Author
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丁莹, 丁烨, 曹婷婷, 牛博申, and 杨立军
- Abstract
Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2017
- Full Text
- View/download PDF
20. Experimental investigation and modelling of the temperature effects on the tensile behavior of textile reinforced refractory concretes.
- Author
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Rambo, Dimas Alan Strauss, Yao, Yiming, de Andrade Silva, Flávio, Toledo Filho, Romildo Dias, and Mobasher, Barzin
- Subjects
- *
FIBER-reinforced concrete , *TEXTILE fibers , *TENSILE strength , *BASALT , *DIGITAL image correlation , *FINITE difference method - Abstract
The work in hand presents results of an experimental and numerical research on the post-heating residual strength of a basalt textile refractory composite submitted to tensile loading. The tensile tests were performed after a preheating process at temperatures ranging from 25 to 1000 °C. The mechanical performance and cracking mechanisms were discussed and compared to that obtained at room temperature. Image analysis by means of digital image correlation method was used to obtain the evolution of crack width which was subsequently correlated with the stress response for all target temperatures. Scanning electron microscopy was used to investigate the damage processes in the fiber–matrix interfaces after exposure to high temperatures. A finite difference model was used to simulate the tension stiffening behavior of TRC (Textile Reinforced Concrete) systems predicting their crack spacing and stress vs. strain responses. The obtained results indicated that due to the coating decomposition the reliability of basalt TRC can only be guaranteed from room temperature to 150 °C. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
21. Numerical and experimental study of an underground water pit for seasonal heat storage
- Author
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Junfeng Yang, Yakai Bai, Ming Yang, Zhifeng Wang, Jianhua Fan, Guofeng Yuan, Longfei Chen, and Xiaoxia Li
- Subjects
Hydrology ,Finite difference model ,Water pit ,060102 archaeology ,Renewable Energy, Sustainability and the Environment ,business.industry ,020209 energy ,Heat losses ,Stratification (water) ,Thermal stratification ,06 humanities and the arts ,02 engineering and technology ,Thermal energy storage ,Storage efficiency ,Renewable energy ,Numerical validation ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,0601 history and archaeology ,SDG 7 - Affordable and Clean Energy ,business ,Seasonal heat storage ,Groundwater - Abstract
Water pit heat storage is an important part of smart district heating systems that integrate various renewable energy sources. This project studied the storage capacity and thermal stratification in a 3000 m3 underground water pit in Huangdicheng, China using a finite difference model of the water pit that was validated by experimental data. The total heat loss from the water pit in the first year was measured to be 98 MWh and the storage efficiency was 62%. Further investigations using the validated model show that approximately 57% of the total heat loss took place through the side wall, 30% through the top and the rest through the bottom of the pit. The heat loss coefficient was largest along the side wall at 0.702 W m−2∙oC−1. Higher charging temperatures create higher temperature differences between the top and bottom of the water pit, i.e. greater thermal stratification. The MIX number increases during most of the charging period and cannot represent the thermal stratification in the water pit during charging while the stratification number more accurately represents the stratification. Therefore, the stratification number is recommended for characterizing stratified water pits.
- Published
- 2020
22. Finite Difference Model of Temperature Fields in Linear Friction Welding
- Author
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I.M. Gatiyatullin, V.R. Galimov, O.V. Murugova, and A.U. Medvedev
- Subjects
010302 applied physics ,Materials science ,Finite difference model ,Numerical modeling ,02 engineering and technology ,Mechanics ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0103 physical sciences ,General Materials Science ,Friction welding ,0210 nano-technology - Abstract
The finite-difference model for calculating temperature fields in linear friction welding is described. A feature of the model is the heat transfer across the friction surface accounting, which makes it possible to study the case of welding parts with different physical and mechanical properties. Modelling results, obtained for combination of VT6 and VT8-1 titanium alloys welding, are described. An assessment of the temperature field and heat transfer during the parts from VT6 and VT8-1 welding is given.
- Published
- 2020
23. Numerical assessment of the impeding effect of check dams in the Hongchun debris flow gully, Sichuan Province, China
- Author
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Wei Shen, Dongpo Wang, Siming He, and Tonglu Li
- Subjects
Hydrology ,Finite difference model ,0211 other engineering and technologies ,Geology ,Numerical assessment ,02 engineering and technology ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Debris ,Debris flow ,Nature Conservation ,Environmental science ,Entrainment (chronobiology) ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences - Abstract
To mitigate potential damage from debris flows, numerous check dams have been constructed in thousands of debris flow gullies all over the world. However, the efficiencies of these check dams are largely unknown because they are normally designed based on empirical methods. This paper presents an assessment of the impeding effect of check dams constructed in the Hongchun debris flow gully in Sichuan Province, China by using an improved finite difference model. Compared with other models, the improved model can consider both the impeding effect of check dams and bed entrainment. We analyzed the impeding effect of these check dams on different initial scales of debris flows. The results show that these check dams perform quite well in constraining bed entrainment downstream of the gully. The average velocity, peak discharge, and final scale of a debris flow in the gully can be substantially reduced by constructed check dams. The impeding effect is sufficient when the initial volume of the debris flow is less than 1.5 times that of the catastrophic debris flow event that occurred in this gully on 14 August 2010. This study improves our understanding of the influence of check dams on the dynamic and bed entrainment processes of debris flows. The model adopted in this study can be a robust tool to quantify the efficiencies of existing check dams and provide reasonable guidance in the design of check dams in debris flow gullies.
- Published
- 2020
24. A finite difference approach to study the impact of boundary conditions on the acoustical behavior of particle stacks
- Author
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Mo, Zhuang, Song, Guochenhao, Shi, Tongyang, and Bolton, J Stuart
- Subjects
Boundary conditions ,Acoustics and Ultrasonics ,Arts and Humanities (miscellaneous) ,Particle stack ,Finite difference model ,Sound absorption - Abstract
The responses of particle stacks to incident sound waves show interesting features that are very different from those of a homogeneous continuum. Further studies of the acoustical performance of particle stacks can help both to discover potential noise control applications of these types of materials, and to help provide better insight into the internal status of the particle stacks. In the current study, a finite difference (FD) model for a particle stack was built based on the Biot poro-elastic theory. The intention in developing this model is to describe the acoustical behavior of particle stacks with consideration of not only the finite stiffness of the particles, but also the influence of gravity and friction between the particles and the inner wall of their enclosure: i.e., the cylindrical sample holder of a standing wave tube, in this work. The derivation of governing equations and boundary conditions is introduced, together with acoustic measurement results of particles stacks consisting of micron-scale glass bubbles, including absorption coefficients and surface impedances that are compared with the theoretical predictions. The possible application scenarios of such materials, and potential developments that will further improve the FD model will also be discussed.
- Published
- 2022
25. A Hybrid Finite Difference Model for Snapback Devices with Lowly Doped Regions in SPICE
- Author
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Guido Notermans, Hans-Martin Ritter, and Steffen Holland
- Subjects
Materials science ,Finite difference model ,business.industry ,Spice ,Doping ,Transistor ,law.invention ,Computer Science::Hardware Architecture ,Snapback ,law ,Optoelectronics ,Diffusion (business) ,Convection–diffusion equation ,business ,Voltage - Abstract
A hybrid finite difference model for SCRs and open base transistors with a lowly doped region is presented. It solves the diffusion and transport equation in a spice simulator. The results are compared with VF-TLP measurements for different rise times and different lengths of the lowly doped region of the devices. A good agreement of the simulated and measured quasi-static and peak voltage is achieved.
- Published
- 2021
26. Sequential Cracking and Their Openings in Steel-Fiber-Reinforced Joint-Free Concrete Slabs.
- Author
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Destrée, Xavier, Yiming Yao, and Mobasher, Barzin
- Subjects
- *
FIBER-reinforced concrete , *CRACKING of concrete , *EXPANSION & contraction of concrete , *FINITE difference method , *BOND strengths , *INTERFACIAL bonding - Abstract
Numerical and empirical models addressing the drying shrinkage cracking behavior of joint-free steel-fiber-reinforced concrete (SFRC) slabs are presented. Effect of water--cement ratio, admixtures, and free shrinkage are considered. Mechanical restrictions including base friction, fiber dosage, and interfacial bond properties restrain the growth of microcracks into main cracks and also reduce crack opening. A model based on a finite-difference equilibrium solution of a one-dimensional (1D) slab on frictional ground simulates the formation and subsequent opening of cracks in the slab. Results are compared with an empirical predictive tool for crack opening. A sensitivity study shows that correlation of predicted crack opening reduced by increasing fiber volume, base friction, and interfacial bond strength. Case studies are conducted on three slabs in service at different occasions and both models are used to predict the crack opening. While these models are developed based on different methodologies, they are related to a great extent by addressing the same mechanical characteristics. A simple method to estimate the slab curl is proposed and a parametric study has been conducted. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
27. Application of 256-channel dense array electroencephalographic source imaging in presurgical workup of temporal lobe epilepsy.
- Author
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Rui Feng, Jie Hu, Li Pan, Jinsong Wu, Liqin Lang, Shize Jiang, Xin Gu, Jun Guo, and Liangfu Zhou
- Subjects
- *
TEMPORAL lobe epilepsy , *ELECTROENCEPHALOGRAPHY , *HEALTH outcome assessment , *BRAIN surgery , *POSITRON emission tomography , *DIAGNOSIS , *PATIENTS - Abstract
Objective: This study evaluated the localization precision of 256-channel dense array electroencephalographic source imaging (dESI) in comparison to conventional noninvasive tools. In addition, the study was designed to analyze the relationship between the 256-channel dESI source patterns and surgical outcome. Methods: Forty-three patients with temporal lobe epilepsy (TLE) who underwent one-stage resective surgeries were recruited in this study. We compared dESI with other noninvasive evaluation methods by comparing results with resections that eliminate or significantly reduced seizures according to sublobule and lobule criteria. Sensitivity and specificity of multiple evaluation methods were calculated. Kaplan-Meier analysis was performed to evaluate the relationship between source patterns and surgical outcome. Results: dESI showed the best sensitivity (sub-lobule, 91.4%; lobule, 97.1%) and specificity (75%) for both sub-lobule and lobule criteria. The Kaplan-Meier survival analysis showed that cases with ''single source'' had better prognosis than with ''multiple sources'' (p < 0.05); cases of ''sources within resection'' showed better surgical prognosis than cases of ''sources outside resection'' (p < 0.05). Conclusion: In this study, 256-channel dESI provided a higher clinical yield than the other most broadly used noninvasive presurgical workup tools. dESI results with ''single source'' correlated strongly to good prognosis, while cases with ''multiple sources'' may cautiously be considered as candidates for one-stage resective surgeries. The resection of the irritative zone identified by interictal epileptiform discharges (IEDs) was related to good surgical prognosis in TLE. Significance: In the presurgical workup of TLE, the clinical yield of 256-channel dESI is high. Patterns of dESI results are related to surgical prognosis, and they can be instructive for presurgical planning. The resection of the irritative zone can be related to good surgical prognosis in TLE. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
28. Wave control of suspended rope based on finite difference model
- Author
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Xiaolan ZHENG and Muneharu SAIGO
- Subjects
suspended rope ,wave control ,finite difference model ,crane rope ,elevator rope ,Mechanical engineering and machinery ,TJ1-1570 ,Engineering machinery, tools, and implements ,TA213-215 - Abstract
This paper treats the wave control of suspended ropes by a control law based on the finite difference model. The control is acted on one finite difference interval inside of the upper fixed end. The control input is the distributed force equivalent to the difference between the boundary node equations and the interior node one. This control compensation of the boundary condition with use of the wave propagating solution of the interior node equation makes the boundary state as if it were the interior nodes. The wave propagating solution of the finite difference model of suspended rope is obtained as the transfer function between adjacent node displacements in the frequency domain that gives the convolution integral kernel function in the time domain. The simulation of the suspended rope systems with or without load mass at the free lower end boundary and with load mass at the fixed lower end boundary have been conducted. The frequency response analysis and numerical time simulation have confirmed the presented wave control effectiveness. The lower end boundary condition of a suspended rope has been also discussed.
- Published
- 2014
- Full Text
- View/download PDF
29. Optimization of Residual Oil Hydrocrackers: Integration of Pump-Free Ebullated Bed Process with Membrane-Aided Gas Recovery System
- Author
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Chen Bo, Fang Xiangchen, Mina Hoorfar, Hailong Ge, Yousif Alcheikhhamdon, Liu Ling, Meng Zhaohui, and Tao Yang
- Subjects
Cracking ,Separation system ,Fuel Technology ,Membrane ,Materials science ,Finite difference model ,business.industry ,General Chemical Engineering ,Residual oil ,Energy Engineering and Power Technology ,Crude oil ,Process engineering ,business - Abstract
The ebullated bed residual oil hydrocracking is a well-established technology wherein the vacuum residue (VR) of crude oil is converted into light valuable oils. This research work targeted to optimize the hydrocracking process by integrating the pump-free ebullated bed reactor (PF-EBR) with a membrane-based gas synthetic recovery system. A PF-EBR hydrocracking unit with a feed capacity of 3 × 106 t/a (ton per annum) of vacuum residues was modeled by the axial dispersion model; the 5-lump axial dispersion model and the finite difference model for PF-EBR and membrane unit were developed and packaged as self-defined extensions in Aspen HYSYS, allowing the integrated process to be evaluated in high efficiency and accuracy; the proposed model was further validated by the experimental data of the pilot and 5 × 104 t/a industrial unit. The results of process optimizations showed that the membrane-aided separation system demonstrated better performance than the conventional condensation system in separating hydr...
- Published
- 2019
30. Dielectric properties of fractured carbonate rocks from finite-difference modeling
- Author
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Sam Yang and Tongcheng Han
- Subjects
chemistry.chemical_compound ,Geophysics ,Finite difference model ,chemistry ,Geochemistry and Petrology ,Fracture (geology) ,Carbonate rock ,Mineralogy ,Carbonate ,Dielectric ,Geology ,Characterization (materials science) ,Finite difference modeling - Abstract
Fractures are common features in virtually all types of geologic rocks and tend to dominate their mechanical and hydraulic properties. Detection and characterization of fractures in rocks are of interest to a variety of geophysical applications. We have investigated the frequency-dependent dielectric properties of fractured porous carbonate rocks in the frequency range [Formula: see text] and their relationships with different types of fluids filling the fractures, fracture connectivity, and directions of electrical field applied to the rocks using numerical simulation methods based on a 3D finite-difference model. We tested the validity of the modeling method on a spherical-shell model with the theoretical analytical solutions. The two fractures in the two digital carbonate rocks have the same length, but in one rock, they intersect and in the other sample they do not. The fractures in the brine-saturated digital rocks are filled either with oil or with the same brine as in the background rock. We found that although conductivity and relative permittivity are sensitive to the fracture-filling fluids, the dielectric loss factor is the best parameter discriminating the fluids. When filled with brine, the fracture connectivity does not affect the dielectric properties of the rocks. When filled with oil, the fracture connectivity can only be detected if the electrical field is parallel to the longer fracture orientation. The results provide new insights into the frequency-dependent dielectric responses of fractured sedimentary rocks and will help with the interpretation of the dielectric data acquired from rocks with fractures.
- Published
- 2019
31. Performance of a thermocouple subjected to a variable current
- Author
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Youness Bouaanani, Eric Gavignet, François Lanzetta, Philippe Baucour, Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Materials science ,Finite difference model ,020209 energy ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,General Engineering ,Experimental data ,02 engineering and technology ,Mechanics ,Heat transfer coefficient ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,[SPI.AUTO]Engineering Sciences [physics]/Automatic ,Thermocouple ,Seebeck coefficient ,[PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph] ,0202 electrical engineering, electronic engineering, information engineering ,[PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] ,Current (fluid) ,0210 nano-technology ,Variable (mathematics) - Abstract
International audience; The aim of this study is to understand the various thermoelectrical phenomena by creating a 1D model that dynamically reacts like a thermocouple through which a current is passed. A new style of modelling is used in this study, which allows the characteristics transition between the two different alloys to be programmable. The main objective is to determine the best parameters that characterize the junction in terms of Seebeck coefficient and heat transfer coefficient in order to obtain a reliable model of the thermocouple. Experiments are performed on an E-type thermocouple of 80 μm in diameter. This thermocouple is subjected to three different types of variable currents. The 1D finite difference model results are compared with the experimental data acquired using an infrared camera. The development of an accurate dynamic model leads to a model exploration of the thermocouple response.
- Published
- 2018
32. (CMMSE paper) A finite‐difference model for indoctrination dynamics
- Author
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María G. Medina-Guevara, Héctor Vargas-Rodríguez, and Pedro B. Espinoza-Padilla
- Subjects
Agent-based model ,Finite difference model ,Opinion dynamics ,General Mathematics ,Dynamics (mechanics) ,Indoctrination ,General Engineering ,Applied mathematics ,Mathematics - Published
- 2018
33. Modeling wave effects on storm surge and coastal inundation
- Author
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Bingchen Liang, Jian Shi, Guoxiang Wu, Fengyan Shi, and James T. Kirby
- Subjects
Environmental Engineering ,Finite difference model ,010504 meteorology & atmospheric sciences ,010505 oceanography ,Storm surge ,Ocean Engineering ,Storm ,Atmospheric sciences ,01 natural sciences ,Surface wave ,Boundary value problem ,Surge ,Wave setup ,Geology ,0105 earth and related environmental sciences ,Storm intensity - Abstract
We present a parametric study of surface wave effects on storm surge and coastal inundation. Hurricane wind forcing terms, atmosphere pressure gradient terms, and radiation open boundary conditions are implemented into an existing quasi-3D nearshore model, NearCoM-TVD, which uses a shock-capturing TVD scheme and can better simulate the wetting-drying process during inundation than a conventional finite difference model. Systematic numerical experiments are carried out in an idealized continental shelf-beach-land system to identify the role of waves in modeling storm surge and inundation under different storm characteristics. Four storm parameters, including storm intensity, storm size, translation speed and incident angle are investigated. Modeling results reveal that the presence of waves can increase the maximum storm surge heights significantly through wave setup, and the contribution of waves varies considerably depending on the storm characteristics. In addition to direct wave forcing, the wave-enhanced bottom stress in the surfzone also promotes higher wave setup and hence higher surge heights. Waves also have a major influence on the maximum inland inundation distance, however, we find that waves do not always favor more inundation as expected. For storms traveling at very slow translation speeds or nearly parallel to the coast, waves surprisingly exert a negative effect on the maximum inundation distance. We argue that wave-enhanced bottom stress combined with longer forcing duration in such storms counteract the positive effect of wave setup, and thus less inundation is predicted in wave-current coupled simulations. Our results highlight the necessity of fully-incorporating wave effects in storm surge and inundation modeling.
- Published
- 2018
34. Estimation of Cable Tension with Unknown Parameters Using Artificial Neural Networks
- Author
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Cuong-Le Thanh, Luu Xuan Le, L. G. To, Hiroshi Katsuchi, and Seyed Ehsan Haji Agha Mohammad Zarbaf
- Subjects
Vibration ,Finite difference model ,Artificial neural network ,Discretization ,Computer science ,business.industry ,Bending stiffness ,Finite difference ,Structural engineering ,Boundary value problem ,business ,Cable tension - Abstract
For existing stay cables, bending stiffness and boundary conditions at cable ends often differ from those of the design owing to the degradation of cable materials and complexity at the cable supports. This paper presents a method for vibration-based cable tension estimation using artificial neural networks (ANNs) regardless of the uncertainties of cable boundary conditions and unknown cable bending stiffness. Finite difference formulation of a discretized cable with rotational restraint ends is developed to generate datasets for training, validation, and testing in ANNs. The proposed method was applied to identify tensions in cables of an existing bridge as a case study. Results showed that the suggested that suggested methodology is highly capable of identifying cable tension with unknown cable bending stiffness and uncertain boundary conditions.
- Published
- 2021
35. A numerical model to simulate the dynamic performance of Breathing Walls
- Author
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Livio Mazzarella, Andrea Alongi, and Adriana Angelotti
- Subjects
Breathing wall ,validation ,Finite difference model ,Discretization ,Building and Construction ,Mechanics ,Dynamic insulation ,building energy simulation ,Computer Science Applications ,symbols.namesake ,Modeling and Simulation ,Dirichlet boundary condition ,Architecture ,symbols ,Breathing ,discretization ,numerical model ,Building energy simulation ,dynamic insulation ,Mathematics - Abstract
A one-dimensional Finite Difference Model for Breathing Wall components under time dependent Dirichlet boundary conditions is presented. The algorithm undergoes a comprehensive validation against a...
- Published
- 2021
36. Finite Difference Heat Exchanger Model: Flow Maldistribution with Thermal Coupling
- Author
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John Zhai, Michael J. Brandemuehl, David Denkenberger, and Joshua M. Pearce
- Subjects
Fluid Flow and Transfer Processes ,Materials science ,Finite difference model ,020209 energy ,Mechanical Engineering ,Finite difference ,02 engineering and technology ,High effectiveness ,Mechanics ,Condensed Matter Physics ,Physics::Fluid Dynamics ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Flow (mathematics) ,Heat exchanger ,0202 electrical engineering, electronic engineering, information engineering ,Thermal coupling - Abstract
Channels not receiving the same amount of flow (flow maldistribution) is an important effectiveness loss for high effectiveness heat exchangers. This paper develops a finite difference model of a counter flow heat exchanger. It reproduced the simple NTU result for two channels exactly. For more than two channels, there is an edge effect, and the model agreed within 0.1% of the literature. Perfect agreement was achieved for a simple flow maldistribution case. For independent pairs of hot and cold channels, as flow rate is reduced, the effectiveness asymptotically approaches the irregularity parameter (a measure of channel flow maldistribution). With thermal coupling between pairs of channels (measured by an equivalent Peclet number), effectiveness continues to increase with decreasing flow rate. These results hold for uncorrelated flow maldistribution on both sides or no flow maldistribution on one side. However, when flow maldistribution is positively correlated, effectiveness is higher; and, when it is negatively correlated, effectiveness is lower. A number of resulting graphs illustrate the effectiveness for each channel with different flow rate and correlation. While one exemplary application is a polymer expanded microchannel heat exchanger, the model could be used for other heat exchangers.
- Published
- 2021
37. A finite difference model for undefined end boundary to analyse the heat transfer in dry sands
- Author
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Somenath Mondal, Anh Minh Tang, Devendra Singh, Jean M. Pereira, National Institute of Technology, Jamshedpur, Indian Institute of Technology Bombay (IIT Bombay), Laboratoire Navier (NAVIER UMR 8205), École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel, and European Project: 612665,EC:FP7:PEOPLE,FP7-PEOPLE-2013-IRSES,GREAT(2014)
- Subjects
finite difference model ,Environmental Engineering ,Materials science ,Finite difference model ,numerical analysis ,020209 energy ,0211 other engineering and technologies ,Soil Science ,Boundary (topology) ,02 engineering and technology ,Physics::Geophysics ,heat transfer equation ,Thermal ,0202 electrical engineering, electronic engineering, information engineering ,Geotechnical engineering ,021101 geological & geomatics engineering ,Soil mass ,business.industry ,thermal regime ,Numerical analysis ,[SPI.GCIV.GEOTECH]Engineering Sciences [physics]/Civil Engineering/Géotechnique ,Mechanics ,Physics::Classical Physics ,Geotechnical Engineering and Engineering Geology ,Heat flux ,13. Climate action ,Heat transfer ,sands ,business ,Thermal energy - Abstract
International audience Accurate prediction of thermal regime (i.e., the variation of soil temperature, θ, and heat flux, ) to investigate the migration of thermal energy in soil mass, poses challenge to the geoenvironmental engineers while dealing with various thermo-active structures. In this context, several numerical approaches have been attempted to solve the heat transfer equation (HTE) for conduction to predict the thermal regime. However, most of them need accurate boundary condition defined and involve complicated numerical approach which is inconvenient for the practising engineers. Hence, an attempt has been made in the present study to develop a simplified, but numerically efficient, approach based on the finite difference method (FDM) to analyse one dimensional heat transfer in dry sands when the end boundary is not defined. Furthermore, a time dependent initial boundary condition has been applied to this model to simulate similar experimental condition and results have been compared vis-à-vis those obtained from the experiment and COMSOL Multiphysics ® to validate the proposed approach.
- Published
- 2020
38. A Study on the Heat Transfer of Surrounding Rock-Supporting Structures in High-Geothermal Tunnels
- Author
-
Hu Yunpeng, Cheng Jiang, Qiling Wang, Mingnian Wang, Yicheng Wang, and Liu Dagang
- Subjects
temperature test ,finite difference model ,Finite difference model ,020209 energy ,02 engineering and technology ,lcsh:Technology ,lcsh:Chemistry ,020401 chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,variable temperature ,General Materials Science ,Geotechnical engineering ,high geothermal tunnel ,0204 chemical engineering ,Instrumentation ,Geothermal gradient ,lcsh:QH301-705.5 ,Fluid Flow and Transfer Processes ,lcsh:T ,Process Chemistry and Technology ,General Engineering ,Excavation ,Radius ,lcsh:QC1-999 ,Computer Science Applications ,Linear relationship ,lcsh:Biology (General) ,lcsh:QD1-999 ,lcsh:TA1-2040 ,Heat transfer ,lcsh:Engineering (General). Civil engineering (General) ,Geology ,lcsh:Physics - Abstract
The temperature distribution is one of the most vital parameters which should be fully considered in high geothermal tunnel design. For the purpose of studying the impact of temperature disturbance caused by construction on temperature distribution of surrounding rock and lining structure in a high geothermal tunnel, a new finite difference model for temperature prediction was proposed. Based on the abundant field test results, forecast analysis for the research of a high geothermal tunnel in this paper is made. The results indicate that the temperature of the surrounding rock near the tunnel sidewall decreases obviously in the first 14 days while that of the surrounding rock far away is stable after tunnel excavation, and the rock temperature showed three ways of change: undulate type (<, 2 m), decline type (2&ndash, 5 m) and stable type (>, 5 m). There is a linear relationship between the initial rock temperature and the released heat of the surrounding rock. The radius of the heat-adjusting layer and the initial rock temperature presents a quadratic function relation. The lining concrete actually cures under the variable high-temperature environment and the real curing temperature decreases with time and becomes stable seven days later. The results would contribute to providing support for high geothermal tunnel research and design
- Published
- 2020
- Full Text
- View/download PDF
39. Implementation of a model of elastoviscoplastic consolidation behavior in Flac 3D
- Author
-
Eduardo Botero Jaramillo, Alexandra Ossa López, and Verónica M. Giraldo Zapata
- Subjects
Finite difference model ,Consolidation (soil) ,Piezometer ,05 social sciences ,Constitutive equation ,0211 other engineering and technologies ,Finite difference method ,02 engineering and technology ,Beaufort sea ,Geotechnical Engineering and Engineering Geology ,Computer Science Applications ,The arctic ,0502 economics and business ,Geotechnical engineering ,050203 business & management ,Geology ,021101 geological & geomatics engineering - Abstract
The implementation of an elastoviscoplastic three-dimensional model (EVP3D) with the finite difference method is presented using the Flac3D analysis platform. This numerical model allows the time-dependent stress-strain behavior of soil to be studied while incorporating its viscous characteristics. An algorithm for solving the constitutive equations is developed and programmed using the centered finite difference method varying in time. The historical case of the construction of Tarsuit Island in the Beaufort Sea in the Arctic Ocean is studied to calibrate and validate the model. A finite difference model that represents the construction stages is developed, and the short- and long-term behaviors are obtained. The model was calibrated and validated with the data record from an electric piezometer that was installed in the foundation of the artificial island, and the results of the algorithm are compared with the recorded data. The results are satisfactory and comparable to the measurements that were recorded for a year on the island, which demonstrates the applicability and validity of the model and its constitutive hypotheses.
- Published
- 2018
40. A modified finite difference model for the modeling of flowslides
- Author
-
Jian Guo, Wei Shen, Ping Li, and Tonglu Li
- Subjects
Centrifugal force ,Finite difference model ,010504 meteorology & atmospheric sciences ,Dam break ,0211 other engineering and technologies ,Landslide ,02 engineering and technology ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Pressure coefficient ,Stability (probability) ,Geotechnical engineering ,Entrainment (chronobiology) ,Mixing (physics) ,Geology ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences - Abstract
In this paper, a modified finite difference model is proposed to simulate the propagation of flowslides. Modifications of the new model are conducted by calculating the lateral pressure coefficient k in the sliding mass and the entrainment and centrifugal effect during the transport process. The strength parameters are modified based on the size of the entrainment to consider the change in the landslide strength due to material mixing. Two dam break problems are simulated to test the accuracy and stability of the numerical scheme, and the results show good agreement with the analytical solutions and the measured data. Then, the model is used to analyze a typical flowslide: the Dagou landslide in Gansu Province, China. The model can accurately predict the details of the motion of the landslide, especially behaviors such as turning along the meandering gully and thrusting on the gully slopes due to centrifugal force.
- Published
- 2018
41. Blockage location in pipelines using an implicit nonlinear finite-difference model optimization
- Author
-
Gildas Besanҫon, Didier Georges, and Ignacio Rubio Scola
- Subjects
Finite difference model ,Computer science ,Acoustics ,Pipeline (computing) ,0208 environmental biotechnology ,02 engineering and technology ,01 natural sciences ,010305 fluids & plasmas ,020801 environmental engineering ,Pipeline transport ,Nonlinear system ,Noise ,Control and Systems Engineering ,0103 physical sciences ,Hardware_INTEGRATEDCIRCUITS - Abstract
In this paper, a new approach for punctual blockage location in pipelines is proposed. This approach is based on an implicit finite-difference modeling of pipeline dynamics including the effect of punctual blockage under study, and on a related optimization: using measurements at both ends of the pipeline, together with an appropriate excitation, the parameters of the blockage are directly identified from a bank of simulators. This methodology is shown to be pretty efficient via simulation results, even in the presence of additive measurement noise.
- Published
- 2018
42. Three Dimensional Finite Difference Model to Study the Thermal Stress in Peripheral Regions of Human Limbs Immediately after Physical Exercise
- Author
-
Babita Kumari and Neeru Adlakha
- Subjects
Materials science ,Finite difference model ,Physical exercise ,General Medicine ,Mechanics ,General Pharmacology, Toxicology and Pharmaceutics ,General Biochemistry, Genetics and Molecular Biology ,Peripheral - Published
- 2018
43. Thermo-mechanical assessment of heated bridge deck under internal cyclic thermal loading from various heating elements: pipe, cable, rebar.
- Author
-
Mehrabi, R., Atefi-Monfared, K., Kumar, D., Deshpande, A.A., and Ranade, R.
- Subjects
- *
BRIDGE floors , *CYCLIC loads , *HEAT pipes , *THERMAL conductivity , *THERMAL expansion , *CONCRETE slabs - Abstract
Heated bridge is an eco-friendly technology where embedded internal heating elements are utilized for deicing/snow melting of the bridge deck surface. A crucial factor preventing wide scale implementation of this technology is the lack of fundamental understanding of the thermo-mechanical behavior of the reinforced slab under cyclic internal thermal loads. This study presents a novel thermo-mechanical assessment of a heated bridge deck subjected to cyclic internal thermal loads implemented through three different heating elements: pipe, cable, rebar. A new finite difference based numerical model was developed and calibrated against small scale laboratory experiments; considering realistic thermal and mechanical boundary conditions, and incorporating thermal-induced degradation of the mechanical properties of concrete. Results revealed a considerably distinct thermo-mechanical response of the concrete slab under each heating system. The cable system resulted in the most substantial thermal-induced internal damage in the concrete slab. Findings indicate that the thermal conductivity and the linear thermal expansion coefficients of the heating elements are key factors governing the thermal efficiency and the extent of the internal damage in a heated concrete slab. A sensitivity analysis suggested that the thermo-mechanical performance of a heated slab can be notably enhanced through initiating heating at higher ambient temperatures, and reducing the depth of placement of the heating elements. • Thermo-mechanical assessment of heated bridge deck to internal cyclic thermal loads. • Heating element thermal conductivity and linear thermal expansion govern efficiency. • Heated cable system generates highest thermal-induced internal damage. • Efficiency enhanced by rebar, shallower heater placement, higher start temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
44. Ground loss model for analyzing shield tunneling-induced surface settlement along curve sections.
- Author
-
Deng, Huang-Shi, Fu, He-Lin, Yue, Shi, Huang, Zhen, and Zhao, Yun-Ya
- Subjects
- *
TUNNEL design & construction , *MINDLIN theory , *FINITE differences , *CURVES , *SOIL mapping - Abstract
• A ground loss model of the curve section. • Surface settlement prediction formula of the curve section. • Surface settlement law of the curve section. • A FDM of shield machine tunneling along the curve section. The shield tunneling along the curve section is widespread in cities. This paper proposes a ground loss model for shield tunneling along such sections. A prediction formula for the surface settlement was deduced using the mirror theory and the Mindlin solution, and a finite difference model was constructed based on the Changsha power tunnel engineering project. The law of surface settlement caused by shield tunneling along a curve section was analyzed. The theoretical prediction results and numerical simulation results were found to be in good agreement with the field monitoring data, proving the correctness of the proposed ground loss model and theoretical prediction formula. The over-cutting gap causes the transverse surface settlement to be asymmetrically distributed, whereas the integrative gap at the shield tail causes it to be symmetrically distributed. The transverse surface settlement curve is nonuniformly distributed in a "V" shape when shield tunneling along the curve section. The surface settlement is maximum inside the curve section, and the settlement value inside the curve section is greater than that outside, which is different from the surface settlement law in the straight section. The nonuniform distribution of the ground loss and shield shell friction was found to be the cause of the uneven surface settlement distribution. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
45. A study on the effects of piled-raft foundations on the seismic response of a high rise building resting on clayey soil
- Author
-
HamidReza Bolouri Bazaz, Ali Akhtarpour, and Abbas Karamodin
- Subjects
Superstructure ,Finite difference model ,0211 other engineering and technologies ,Soil Science ,020101 civil engineering ,Economic shortage ,Excavation ,02 engineering and technology ,Geotechnical Engineering and Engineering Geology ,0201 civil engineering ,Shear (sheet metal) ,Current (stream) ,Structural load ,Soil water ,Geotechnical engineering ,Geology ,021101 geological & geomatics engineering ,Civil and Structural Engineering - Abstract
Piled-raft foundations are often used to transfer the structural load to the depth of the soil and tall structures can be constructed on medium to soft soils by utilizing a group of piles. The static effects of a group of piles are quite evident while their dynamic effects are quite unknown and therefore, not considered in the design of the superstructure. In the present research, the performance of pile-raft foundations on the seismic response of a 20-story benchmark building resting on soft clayey soil has been investigated using a 2D finite difference model, namely FLAC. The study has been carried out by analyzing the seismic response of the structure with and without pile-raft foundations, on the surface and inside an excavation. The results show that when the structure is constructed on the surface, piled-raft foundations have a significant beneficial effect on the seismic response of the superstructure, for instance a 40% decrease in the base shear. In the case where the structure is located inside an excavation the use of piled-raft foundations are not noteworthy and do not have a considerable effect. The results of this study give an insight on the effects of pile-raft foundations on the seismic response of a superstructure to overcome the current shortage of information in this area and to better predict the behavior of tall structures in soft soil situations.
- Published
- 2021
46. Numerical Study of Thermal Diffusion and Diffusion Thermo Effects in a Differentially Heated and Salted Driven Cavity Using MRT-Lattice Boltzmann Finite Difference Model
- Author
-
Frédéric Kuznik, Sauro Succi, Soufiene Bettaibi, and Ezeddine Sediki
- Subjects
Materials science ,Finite difference model ,Mechanics of Materials ,Combined forced and natural convection ,Mechanical Engineering ,Lattice Boltzmann methods ,General Materials Science ,Square cavity ,Mechanics ,Diffusion (business) ,Thermal diffusivity - Abstract
We perform a numerical study of thermal diffusion and diffusion thermo effects on double diffusive mixed convection in a driven square cavity, differentially heated and salted using a hybrid lattice Boltzmann solver. The multiple relaxation time (MRT) for the lattice Boltzmann equation is used to obtain the velocity field whereas the temperature and concentration fields are deduced from energy and species balances equations using a finite difference method (FDM). The model is validated, resulting in satisfactory agreement with data from the literature. The different validations demonstrate the effectiveness of the proposed approach. Besides, the results showed that the Soret and Dufour numbers have great effects on the flow structure and heat and mass transfer.
- Published
- 2021
47. Modelling the thermal conductivity of a melting snow layer on a heated pavement
- Author
-
Anne D.W. Nuijten and Knut Vilhelm Høyland
- Subjects
021110 strategic, defence & security studies ,Snow melting ,Finite difference model ,Materials science ,010504 meteorology & atmospheric sciences ,0211 other engineering and technologies ,Energy balance ,Insulator (electricity) ,02 engineering and technology ,Geotechnical Engineering and Engineering Geology ,Snow ,01 natural sciences ,Thermal conductivity ,Snowmelt ,Thermal ,General Earth and Planetary Sciences ,Geotechnical engineering ,Composite material ,0105 earth and related environmental sciences - Abstract
A snow layer on a heated pavement strongly affects the energy balance at the pavement surface. Freshly fallen snow has a fairly low thermal conductivity and acts as a good insulator. The thermal properties can vary greatly during the melting process. This study looks into the change of the thermal conductivity during the melting process of dry uncompressed and compressed snow on heated pavements. The energy balance of the heated pavement system is described and the effective thermal conductivity of the melting snow layer during the melting process of snow on a heated pavement system is calculated based on the volume fractions and thermal conductivity of ice, water and air. The results show that the thermal conductivity of an uncompressed and compressed melting snow layer on a heated pavement can be best described as a combination of a parallel and series system. Ice and air are modelled as a series system and water and ice/air are modelled in parallel.
- Published
- 2017
48. Study on different finite difference methods at skin interface for burn prediction in protective clothing evaluation
- Author
-
Martin Camenzind, Lina Zhai, René M. Rossi, and Jun Li
- Subjects
Burn injury ,Finite difference model ,Polymers and Plastics ,Grid size ,Numerical analysis ,Interface (computing) ,Metals and Alloys ,Finite difference method ,Skin temperature ,020101 civil engineering ,02 engineering and technology ,General Chemistry ,Mechanics ,021001 nanoscience & nanotechnology ,0201 civil engineering ,Electronic, Optical and Magnetic Materials ,Homogeneous ,Ceramics and Composites ,Forensic engineering ,Environmental science ,0210 nano-technology - Abstract
Summary For protective clothing evaluation by using the flame engulfment method, a skin burn injury model is required to predict burn degree of the covered skin. By applying finite difference methods, 2 numerical methods are compared. One is based on equivalent heat intensity; the other is based on the law of conservation of energy. In this study, skin temperature rise is compared between these 2 methods by using homogeneous skin properties as well as the analytical solutions. Differences between these 2 methods in application of measured heat exposure tests data are also explored. The results show that assuming equivalent heat intensity at the skin layer interfaces overestimates severity of burn injury. Burn injury time is sensitive to the investigated numerical methods, especially for third-degree burns. The differences of the 2 methods can be reduced by optimization of the grid size using the test cases described in ASTM F1930. A detailed description of requirements regarding applicable numerical methods in future revisions of the relevant standards is recommended. The finite difference model applied in this paper can act as an effective tool to predict temperature distribution in the skin as well as predict burn injury for evaluation of thermal protective clothing.
- Published
- 2017
49. A Finite Difference Model for Calderón’s Boundary Inverse Problem *
- Author
-
Kazuo Amano
- Subjects
Finite difference model ,Mathematical analysis ,Boundary (topology) ,Inverse problem ,Mathematics - Published
- 2019
50. A numerical model for estimating the removal of volatile organic compounds in laboratory-scale treatability tests for thermal treatment of NAPL-impacted soils
- Author
-
Chen Zhao, Kevin G. Mumford, Bernard H. Kueper, and Qianli Xie
- Subjects
Volatile Organic Compounds ,Finite difference model ,Petroleum engineering ,0207 environmental engineering ,Water ,02 engineering and technology ,Thermal treatment ,010501 environmental sciences ,Laboratory scale ,Thermal conduction ,01 natural sciences ,Temperature measurement ,Soil ,Boiling ,Soil water ,Calibration ,Environmental Chemistry ,Environmental science ,Soil Pollutants ,020701 environmental engineering ,Water Pollutants, Chemical ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
Treatability tests can be carried out to assess the potential effectiveness of thermal treatment technologies under different site conditions and are important for specific technology selection and design. In order to reduce the costs for laboratory tests and expand the insights from previous treatability studies, a one-dimensional (1D) radial finite difference model was developed to simulate the removal of volatile organic compounds (VOCs) in laboratory thermal treatability tests. The processes considered in the model include heat conduction, co-boiling of single-component or multi-component NAPLs with water, and water boiling. An explicit approach is used to simulate the evolution of NAPL composition for multi-component NAPLs during heating. The developed model adopts only two fitting parameters and was calibrated and validated using previous laboratory experiments. In this paper, the developed model was first calibrated to three laboratory experiments using temperature measurements, which resulted in matches to the NAPL and gas saturations. After calibration, the model was able to predict the temperature, NAPL and gas saturations for the remaining seven experiments, including those with single and multi-component NAPLs, using the average value of each fitting parameter.
- Published
- 2019
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