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This paper aims to investigate the effect of liquid heterogeneity on sloshing in a two-dimensional rectangular tank. The container is excited horizontally, and the density of the liquid at equilibrium can almost be considered a linear dependence of the depth. The linearized equations representing the sloshing phenomenon are solved numerically using ANSYS 2020 R2 software and analytically using the separation method of variables in conjunction with the Fourier analysis. On the other hand, a comparison study has been carried out between the obtained results and other works related to the same phenomenon. Overall, the results exhibit considerable effects of variation in the Heterogeneity Coefficient β on the free surface's motion and the pressure distribution within the liquid. Furthermore, the free surface of liquid heterogeneity is also affected by the variation of Excitation Frequency Ω and the Filling Rate h of the liquid in the tank. [ABSTRACT FROM AUTHOR]

This research investigates liquid sloshing in a 3D rigid rectangular tank. The impact of rigid baffle on sloshing frequencies has been studied. The mathematical model has been developed using potential theroy. The boundary value problem has an analytical solution in terms of velocity potential with undetermined frequency. We get a system of homogeneous algebraic equations using boundary and free surface conditions. The frequencies are calculated using the non-trivial solution condition. Frequencies of baffled tank are computed for various filling levels. The effects of filling level on frequencies are identified. ANSYS software is used to report the liquid domain and rigid baffle mode forms. [ABSTRACT FROM AUTHOR]

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This paper examines the movement of waves that occur in a fuel tank—both with and without a wave breaker—when a car is travelling at a constant speed and then suddenly brakes. This phenomenon is known as slosh noise, and the paper presents an analysis of the movement of free surfaces in relation to the level of noise generated. The paper focuses on mathematical models of the fluid flow for both tanks—one without any technical solutions for breaking waves, and the other with a solution for breaking waves. The model is constructed based on a set of initial hypotheses about the fluid flow within the tank, by developing the speed potential in a series of fundamental solutions and considering the main variables that affect the phenomenon of sloshing, such as the depth of the liquid, the tank's geometry, and the frequency and amplitude of the initial external force acting on the tank. The analysis of free surface movement is used to find the correlation with the sound generated in the tank. Nonlinearities that arise from the sudden braking are also modelled and numerically studied using MATLAB software. Following the mathematical model, a technical wave-breaking solution was implemented and tested, and it was shown that the amplitude of the movement of the free surface is reduced by half. Further research on the correspondence between the free surface movement based on the behaviour of potential energies in the two cases may be developed. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum Polonorum: Architectura is the property of Wydawnictwo SGGW 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.)

Hydrodynamics-based design of an anoxic bioreactor tank is one of the serious challenges in wastewater industry. Poor fluid flow may cause settlement and therefore reduce the biological performance of a bioreactor. Whilst, a successful bioreactor design can facilitate the enhancement of biological process efficiency and reduction of energy consumption so that the investment and operation cost can be kept as low as possible. In the present study, three-dimensional computational fluid dynamics models for three common full-scale bioreactor configurations were simulated using a single-phase flow model and the standard two-equation SST k–ε turbulence model. The main objective of this numerical study is to investigate the effect of bioreactor geometry on the hydrodynamics performance of the flow field. Four submerged impellers were modelled for each tank geometry and three thrust scenarios were considered in order to evaluate the effect of changing impeller thrust on the flow velocity distribution inside each tank. The results show that the orbal bioreactor geometry has better performance in driving the flow field with more uniform flow patterns than other bioreactor configurations. The minimum flow velocity required was achieved in orbal tank to maintain the micro-organism particles suspended in the wastewater media at certain mixing power. [ABSTRACT FROM AUTHOR]

This paper examines the movement of waves that occur in a fuel tank—both with and without a wave breaker—when a car is travelling at a constant speed and then suddenly brakes. This phenomenon is known as slosh noise, and the paper presents an analysis of the movement of free surfaces in relation to the level of noise generated. The paper focuses on mathematical models of the fluid flow for both tanks—one without any technical solutions for breaking waves, and the other with a solution for breaking waves. The model is constructed based on a set of initial hypotheses about the fluid flow within the tank, by developing the speed potential in a series of fundamental solutions and considering the main variables that affect the phenomenon of sloshing, such as the depth of the liquid, the tank’s geometry, and the frequency and amplitude of the initial external force acting on the tank. The analysis of free surface movement is used to find the correlation with the sound generated in the tank. Nonlinearities that arise from the sudden braking are also modelled and numerically studied using MATLAB software. Following the mathematical model, a technical wave-breaking solution was implemented and tested, and it was shown that the amplitude of the movement of the free surface is reduced by half. Further research on the correspondence between the free surface movement based on the behaviour of potential energies in the two cases may be developed.

Sloshing makes it challenging to transport liquid-containing systems fast. Accurate prediction and effective suppression of sloshing are essential in many industrial applications. Two different methods are commonly used to numerically investigate the sloshing phenomenon: CFD simulation and equivalent mechanical model. Due to each method's pros and cons, the solutions based on potential flow theory can be a good alternative for sloshing study. However, previous studies mostly focused on sloshing under sinusoidal oscillations, and only a little effort has been made to understand and suppress the sloshing under point-to-point movements. In this study, potential solutions for sloshing in a rectangular tank under horizontal point-to-point movements are newly derived and verified by comparing with the present CFD results. So far, the velocity profile of liquid-containing tanks has attracted little attention from the sloshing suppression point of view. However, simply a suitable choice of velocity profile (acceleration/deceleration duration) can lead to much-reduced sloshing. Results show that the present potential solutions are beneficial for designing the tank velocity profile for minimum residual sloshing under a given condition. It is also shown that the acceleration/deceleration duration affects the sloshing amplitude more significantly than its magnitude. [ABSTRACT FROM AUTHOR]

Conventional liquefied natural gas (LNG) cargo vessels are imposed with tank-fill limitations as precautions to prevent structural damage and stability-loss due to high-impact sloshing, enforcing cargo volume-fills to be lower than 10% or higher than 70% of the tank height. The restrictions, however, limit commercial operations, specifically when handling spot trades and offshore loading/unloading at multiple ports along a shipping route. The study puts forward a computational fluid dynamic (CFD) sloshing analysis of partially-filled chamfered rectangular tanks undergoing sinusoidal oscillatory kinetics with the use of the explicit volume-of-fluid and non-iterative time-advancement schemes. Establishing a 20% to 60% fill-range, the sloshing dynamics were acknowledged within an open-bore, partitioned, and perforated-partitioned tank when oscillating at frequencies of 0.5 Hz and 1 Hz. The overall torque and static pressure induced on the tank walls were investigated. High-impact slamming at the tank roof occurred at 40% and 60% fills, however, the implementation of the partition and perforated-partition barriers successfully reduced the impact due to suppression and dissipation of the wave dynamics.

In this study, a new type of tank roof form is suggested to reduce the high impact forces caused by sloshing. Using this roof allows the tank designers to consider less freeboard, which is economically valuable. For this purpose, an experimental investigation has been implemented to evaluate the efficacy of the proposed roof to distribute the contained liquid impact forces in several time stages. In these experimental measurements, a series of shaking table tests are conducted for a partially filled tank under harmonic and various earthquake excitations for both typical and proposed tank roof forms. The liquid impact forces are reasonably evaluated and compared for both types of tank roof. The efficacy of the proposed roof design is validated by experimental results and it is shown that the sloshing loads can significantly be reduced up to an average of 50% for the dimensions considered in the experiments.

The stability of the boom system of sprayers is easily affected by the liquid sloshing force and the uniformity of droplet deposition deteriorates. Therefore, the liquid sloshing forces in the rectangular tank were measured through experiments. Three main factors affecting the sloshing forces were examined. Experimental results reveal that the sloshing forces measured fit well with the theoretical curve and the maximum sloshing force is independent of the excitation amplitude for a violent sloshing. Based on these characteristics, a practical method was proposed which can approximately calculate the maximum sloshing force based on the linear model, and can be used for the sprayer chassis design and active and passive control of boom attitude. [ABSTRACT FROM AUTHOR]

The primary purpose of the research is to study the effect of free surface nonlinearity in the overall slosh dynamics of base-isolated liquid tank by developing a nonlinear finite element model under different frequency content of earthquakes. Six natural earthquakes are considered, which are categorized under low-, intermediate-, and high-frequency contents. The mixed Eulerian and Lagrangian technique is adopted based on the potential flow theory for developing the fluid domain. The efficacy of the developed computational model is verified with the existing results. The potential constraints of linear responses are demonstrated alongside the dominance of nonlinear counterparts. The slosh amplitudes are underestimated in the linear model, which emphasizes the importance of the present nonlinear approach in adequately determining the freeboard to prevent loss of liquid due to spillage and unexpected roof failure. The laminated rubber bearing isolator played a crucial role in reducing the total and impulsive components of hydrodynamic pressure as well as base shear for both linear and nonlinear approaches. However, the effect of nonlinearity is significant in the contribution of the convective component of pressure and base shear, irrespective of the frequency content of earthquakes. Also, the nonlinear convective base shear is greater than the linear counterpart for non-isolated and base-isolated tanks, and such phenomenon is marginal for higher frequency content motions. Furthermore, resonant studies of both the tank systems are performed using a harmonic ground acceleration. The seismic parameters of the base-isolated tank are amplified when the excitation frequency is very close to its fundamental sloshing frequency rather than the natural frequency of the isolator. • Dynamic response of a base-isolated liquid tank is numerically examined using laminated rubber bearing. • A hybrid Lagrangian and Eulerian framework governs the nonlinear effects of liquid sloshing. • Frequency domain analyses are performed for the dynamic response parameters. • Resonance effects of different tank systems are examined comprehensively for different resonant conditions. • Total and impulsive responses can be efficiently minimized, thus mitigating probable damage to the tanks. [ABSTRACT FROM AUTHOR]

Abstract This paper intends at numerically analyzing the simultaneous influences of base-isolator system and vertical baffle on the seismic performance of a three-dimensional (3D) rectangular liquid storage container, presuming irrotational, inviscid, and incompressible flows. A boundary element technique with meaningful computational efficiency is primarily formulated to treat the spectral problem of liquid motion using the zoning method including the velocity potentials alone of the half free-surface length, which is coupled with Finite elements for tank wall using equilibrium and compatibility conditions. In the soil/foundation component, the foundation is modeled by shell finite elements and the half-space soil medium is modeled employing the external boundary elements, which fulfill the radiation condition of homogeneous media. Eventually, above two parts are attached to equation for isolator motion in the time domain, to attain the total system's nonlinear seismic response. The validity and efficiency of the present coupled numerical method is confirmed against available theoretical solutions and numerical predictions, revealing a good agreement with benchmark results. The sensitivity of base forces, the maximum hydrodynamic pressure and liquid oscillation in relation to some system parameters involving the baffle height, the base-isolator stiffness and the soil properties have been highlighted. Highlights • Laterally excited baffled rectangular container isolated by bilinear bearings is seismically analyzed. • A computer program is coded for the simulation of liquid-structure-soil interaction problem. • Several parameters including tank geometry, isolator stiffness, soil stiffness and baffle configuration are considered. • Broad new findings including some practical comments have been presented. [ABSTRACT FROM AUTHOR]

Abstract In this study, sloshing response of liquid is investigated in partially filled rectangular tanks subjected to earthquake ground motions. To verify the numerical modeling, shaking-table tests were carried out in sub-scale tanks for different excitation amplitudes, frequencies and fill water levels. Using the calibrated models, nonlinear numerical simulations were performed for practical tanks under different horizontal and vertical near fault excitations. The results express that the liquid pressure induced on tank under vertical seismic loading can be increased especially in near-field earthquakes, however, its effect on sloshing wave height is negligible. Also the results for different tanks under both horizontal and vertical earthquakes show that free surface vertical displacement depends on the spectral response acceleration at the first fundamental period of sloshing behavior. Moreover, the induced pressure is strongly influenced by the earthquake peak ground acceleration and also by the spectrum response acceleration at the first sloshing mode. Highlights • Experimental tests in sub-scale tanks for different excitations and fill water level. • The effect of vertical seismic loading on sloshing wave height is negligible. • PGA and spectrum acceleration at first sloshing mode influence on walls pressure. • Spectral acceleration of first sloshing mode affects vertical displacement of wave. [ABSTRACT FROM AUTHOR]

The main topic of the paper is dimensioning steel liquid storage tank, rectangular in shape, with three compartments. Depending on the investor's request (dimensions required for the tank and maximum use of space) a need arose for structure with atypical shape. Austenitic stainless steel is used in this example what is recommended for use in aggressive environments. Dimensioning of steel plates, stiffened and unstiffened, according to Eurocode is carried out according to EN 1993-1-7, which refers to plates loaded out of their plane. Within the first part of the analysis dimensioning is performed according to Eurocode 3. The second part of the paper represents comparative analysis of results obtained according to Eurocode and results obtained using previous domestic standard SRPS.MZ.3. 054. (1981).

In this study, a new type of tank roof form is suggested to reduce the high impact forces caused by sloshing. Using this roof allows the tank designers to consider less freeboard, which is economically valuable. For this purpose, an experimental investigation has been implemented to evaluate the efficacy of the proposed roof to distribute the contained liquid impact forces in several time stages. In these experimental measurements, a series of shaking table tests are conducted for a partially filled tank under harmonic and various earthquake excitations for both typical and proposed tank roof forms. The liquid impact forces are reasonably evaluated and compared for both types of tank roof. The efficacy of the proposed roof design is validated by experimental results and it is shown that the sloshing loads can significantly be reduced up to an average of 50% for the dimensions considered in the experiments. [ABSTRACT FROM AUTHOR]

The article presents the results of validation of static calculations carried out for a monolithic rectangular tank with walls of trapezoidal cross-section. Static calculations were made with the use of software based on the finite element method (FEM) and the finite difference method (FDM) in terms of energy (including spatial static work of the tank). Validation of the results was conducted on a concrete tank model using an innovative measurement tool, i.e. a coordinate measuring arm with a touch probe. [ABSTRACT FROM AUTHOR]

Ground-supported tanks are used to store a variety of liquids. During earthquake activity the liquid exerts impulsive and convective pressures (sloshing) on the walls and bottom of the rectangular tank. This paper provides theoretical background for analytical calculating of circular frequencies and hydrodynamic pressures developed during an earthquake in rectangular container. Analytical results of first natural frequency are compared with experiment.

A study on sloshing characteristics in a rectangular tank, which is horizontally excited with a specific range of the Reynolds number, is approached numerically. The nonlinearity of sloshing flow is confirmed by comparing it with the linear solution based on the potential theory, and the time series results of the sloshing pressure are analyzed by Fast Fourier Transform (FFT) algorithm. Then, the pressure fluctuation phenomena are mainly observed and the magnitude of the amplitude spectrum is compared. The results show that, when the impact pressure is generated, large pressure fluctuation in a pressure cycle is observed, and the effects of the frequencies of integral multiples when the fundamental frequency appears dominantly in the sloshing flow.

The damping effect of the vertical baffles inside a liquid storage tank is studied in this paper. A numerical model based on the finite volume method is established and used to evaluate the accuracy of an analytical model developed to estimate the hydrodynamic damping caused by the vertical wall bounded baffles. For this purpose, several full scale baffled tanks with different aspect ratios are numerically analyzed. The numerical results were then used to validate the analytical model. The reduction in sloshing wave height caused by the baffles is estimated for selected tanks subjected to the seismic excitations. Finally, a simple procedure to estimate the reduction in sloshing amplitude due to the presence of baffles is proposed and validated using the time history numerical results. [ABSTRACT FROM AUTHOR]

In this paper, a design procedure using the generalized single degree of freedom (SDOF) system is proposed for two-dimensional dynamic response of rectangular liquid containing structures (LCS). The proposed model considers the effect of flexibility of tank wall on hydrodynamic pressures and uses the consistent mass approach in dynamic analysis. The contribution of higher modes to the dynamic response of LCS is included in the proposed model. The square root of sum of squares method is proposed for the combination of the first two modes. One set of calculations for a tall tank is presented and compared with the results obtained using the current practice as well as the finite element method reported by the authors in previous investigations. The proposed method using the generalized SDOF system can be simply used in seismic design of LCS. [ABSTRACT FROM AUTHOR]

Sloshing dapat diartikan sebagai gerakan bebas dari fluida cair di dalam sebuah wadah . Masalah sloshing menjadi fenomena penting dalam tangki muatan cair, karena dapat menyebabkan kerusakan pada struktur dalam tangki . paper ini menjelaskan pengaruh besarnya pressure pada tangki kotak dengan dan tanpa penambahan pelat memanjang (baffle) ketika terjadi sloshing yang diakibatkan gerakan rolling yang terjadi pada kapal. Pemodelan tangki dilakukan 2D berbentuk tanki kotak (rectangular tank) dengan ukuran panjang 46.92 m dan tinggi 32.23 m menggunakan software gambit,. variasi model tangki ada 2 yaitu tanpa dan dengan penambahan 1 buah baffle dengan ukuran tebal 1 m dan tinggi 6 m dengan ketinggian cairan 15%, 45%, dan 75%. Proses simulasi dilakukan dengan meode Computational Fluid Dynamic (CFD) menggunakan software Fluent. Dari hasil simulasi dapat disimpulkan bahwa baffle berhasil berfungsi sebagai peredam pressure ketika volume muatan lebih rendah dari tinggi baffle yaitu dalam hal ini volume 15%, namun ketika pada volume muatan 45% dan 75% baffle tidak dapat berfungsi sebagai peredam pressure karena adanya baffle dapat menimbul gaya permukaan cairan ketika cairan lng menghantam baffle yang menyebabkan tinggi cairan lng menjadi lebih tinggi sehingga ketika terjadi gerakan tangki maka dapat menambah besar pressure untuk menghantam dinding-dinding tangki.

SUMMARY In this paper, an analytical method is proposed to determine the dynamic response of 3-D rectangular liquid storage tanks with four flexible walls, subjected to horizontal seismic ground motion. Fluid-structure interaction effects on the dynamic responses of partially filled fluid containers, incorporating wall flexibility, are accounted for in evaluating impulsive pressure. The velocity potential in which boundary conditions are satisfied is solved by the method of separation of variables using the principle of superposition. The impulsive pressure distribution is then computed. Solutions based on 3-D modeling of the rectangular containers are obtained by applying the Rayleigh-Ritz method using the vibration modes of flexible plates with suitable boundary conditions. Trigonometrical functions that satisfy boundary conditions of the storage tank such that the flexibility of the wall is thoroughly considered are used to define the admissible vibration modes. The analysis is then performed in the time domain. Moreover, an analytical procedure is developed for deriving a simple formula that evaluates convective pressure and surface displacements in a similar rigid tank. The variation of dynamic response characteristics with respect to different tank parameters is investigated. A mechanical model, which takes into account the deformability of the tank wall, is developed. The parameters of such a model can be obtained from developed charts, and the maximum seismic loading can be predicted by means of a response spectrum characterizing the design earthquake. Accordingly, a simplified but sufficiently accurate design procedure is developed to improve code formulas for the seismic design of liquid storage tanks. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A liquid sloshing experimental rig driven by a wave-maker is designed and built to study liquid sloshing problems in a rectangular liquid tank with perforated baffle. A series of experiments are conducted in this experimental rig to estimate the free surface fluctuation and pressure distribution by changing external excitation frequency of the shaking table. An in-house CFD code is also used in this study to simulate the liquid sloshing in three-dimensional (3D) rectangular tank with perforated baffle. Good agreements of free surface elevation and pressure between the numerical results and the experimental data are obtained and presented. Spectral analysis of the time history of free surface elevation is conducted by using the fast Fourier transformation. [ABSTRACT FROM AUTHOR]

Abstract: An analytical method is proposed to determine the dynamic response of 3-D rectangular fluid containers with four flexible walls, subjected to seismic ground motion. By applying Rayleigh–Ritz method using the vibration modes of flexible plates, fluid–structure interaction effects on the dynamic responses of fluid containers are considered. A mechanical model, which takes into account the deformability of the tank wall, is developed. The maximum seismic loading of the base at the tank and a section immediately above it can be predicted by this model. Accordingly, a 2-D simplified model is proposed to evaluate pressure distribution on the flexible tank wall. [Copyright &y& Elsevier]

Abstract: The paper describes a simple, efficient and reasonably accurate analytical model for analysis of backfill-rectangular tank–fluid interaction systems. The presented model uses Housner''s two-mass approximation for fluid interaction and mass-spring-dashpot system for backfill interaction and accommodates a variety of features that may affect the behavior of rectangular tanks including fluid volume, backfill geometry, soil properties and flexible/rigid wall types. Unlike the conventional finite element and the finite difference models that require considerable effort and knowledge to prepare the input data, the proposed model requires only a few pieces of data to define the problem and control the analysis. A series of finite element simulations were also fulfilled on two real rectangular tanks subjected to backfill and fluid effects. A reasonably good accord was obtained comparing the analytical predictions to results from numerical simulations. Thus, it can be stated that the model may be used effectively to perform a broad suite of parametric studies at the design stage and also as a reliable tool for estimating the system behavior. The results obtained from parametric seismic analyses indicated that backfill interaction, wall flexibility and fluid interaction considerably affect the lateral displacements. The sloshing response, however, was not practically affected by the backfill interaction and the wall flexibility. [Copyright &y& Elsevier]

Abstract: In this paper and based on the linear potential theory of a fluid and an analogical approach, a supplementary, (complete) exact solution of an equivalent model is developed for a sloshing fluid in a rectangular tank and is compared with the existing solutions given by Graham and Rodriguez, Housner and a semi-analytical/numerical method. The results indicate that Graham and Rodriguez did not provide the correct location expressions for the convective masses. The expressions for the impulsive mass and its position given by Housner are not completely satisfactory approximations of the exact solutions. The solution in this paper can be an exact formulation to supplement the famous, traditional formulations given by Graham and Rodriguez as well as Housner. [Copyright &y& Elsevier]

Abstract: A three-dimensional soil–structure–liquid interaction is numerically simulated using the finite element method in order to analyze the seismic behavior of partially filled concrete rectangular tanks subjected to different ground motions. In this paper, the effect of earthquake frequency content on the seismic behavior of fluid rectangular tank system is investigated using four different seismic motions. A simple model with viscous boundary is used to include deformable foundation effects as a linear elastic medium. This method is capable of considering both impulsive and convective responses of liquid-tank system. Six different soil types defined in the well-recognized seismic codes are considered. The sloshing behavior is simulated using linear free surface boundary condition. Two different finite element models corresponding with flexible shallow and tall tank configurations are studied under the effects of longitudinal, transversal and vertical ground motions. By means of changing the soil properties, comparisons are made on base shear, base moment and sloshing responses under different ground motions. It is concluded that the dynamic behavior of the fluid–tank–soil system is highly sensitive to frequency characteristics of the earthquake record. [Copyright &y& Elsevier]

The sloshing of inviscid liquid of stratified density in a rectangular tank is analyzed. As the flow is no longer irrotional, the governing equation is found to be quite different from the Laplace equation used for the liquid of constant density. In particular it contains terms of mixed temporal and spatial derivatives. The problem is solved based on the variable separation method and Laplace transform for the constant Vaisala-Brunt frequency. It is found that the stratification of density may have small effects on those natural frequencies associated with the constant density, but many new natural frequencies have appeared as a result of its effect. [ABSTRACT FROM AUTHOR]

In this study, the finite-element method is used to investigate the seismic behavior of rectangular liquid tanks in two-dimensional space. This method is capable of considering both impulsive and convective responses of liquid-tank system. Two different finite-element models corresponding with shallow and tall tank configurations are studied under the effects of both horizontal and vertical ground motions using the scaled earthquake components of the 1940 El-Centro earthquake record. The containers are assumed fixed to the rigid ground. Fluid-structure interaction effects on the dynamic response of fluid containers are taken into account incorporating wall flexibility. The results show that the wall flexibility and fluid damping properties have a major effect on seismic behavior of liquid tanks and should be considered in design criteria of tanks. The effect of vertical acceleration on the dynamic response of the liquid tanks is found to be less significant when horizontal and vertical ground motions are considered together. The results in this study are verified and compared with those obtained by numerical methods and other available methods in the literature. [ABSTRACT FROM AUTHOR]

This paper presents the results of parametric studies on the seismic response of concrete rectangular liquid storage tanks using the generalized single-degree-of-freedom (SDOF) system. The effects of height of liquid and width of tank on the dynamic response of liquid storage tanks are investigated. The liquid level varies from the empty condition to a full tank. Also, instead of the commonly used ratio of width of tank to liquid height, Lx/HL, the ratio of width of tank to full height of the tank wall, Lx/Hw, is used as a characteristic parameter of tanks to study the effect of tank size on the dynamic response. The trends of added mass of liquid, effective height, and natural frequencies for different sizes of tanks are established. The values of the added mass of liquid due to impulsive hydrodynamic pressure and the effective height in the relationship with the ratios Lx/Hw and HL/Hw are determined and can be used in the seismic design of liquid storage tanks. Since the natural frequencies of liquid-containing structures are within a band of frequencies between that of a full tank and that of an empty tank, the recommended frequency to be used in the design of the tank wall is the frequency that causes the maximum dynamic response . [ABSTRACT FROM AUTHOR]

Conventional liquefied natural gas (LNG) cargo vessels are imposed with tank-fill limitations as precautions to prevent structural damage and stability-loss due to high-impact sloshing, enforcing cargo volume-fills to be lower than 10% or higher than 70% of the tank height. The restrictions, however, limit commercial operations, specifically when handling spot trades and offshore loading/unloading at multiple ports along a shipping route. The study puts forward a computational fluid dynamic (CFD) sloshing analysis of partially-filled chamfered rectangular tanks undergoing sinusoidal oscillatory kinetics with the use of the explicit volume-of-fluid and non-iterative time-advancement schemes. Establishing a 20% to 60% fill-range, the sloshing dynamics were acknowledged within an open-bore, partitioned, and perforated-partitioned tank when oscillating at frequencies of 0.5 Hz and 1 Hz. The overall torque and static pressure induced on the tank walls were investigated. High-impact slamming at the tank roof occurred at 40% and 60% fills, however, the implementation of the partition and perforated-partition barriers successfully reduced the impact due to suppression and dissipation of the wave dynamics. [ABSTRACT FROM AUTHOR]

Abstract: The hydrodynamic behaviour of a pilot-scale sedimentation tank has been analyzed as a function of the flow and type of feed. As part of a qualitative approach, the main flow lines have been determined under different experimental conditions, including the purge ratio, which does not seem to significantly affect flow patterns. Quantitative analysis has been carried out by the study of the residence times distribution (RTD) in order to quantify the volumes of the different regions of the settler, including dead volumes, and in order to establish the model (dispersion model, tank in series model and a combined model) that better describes the hydrodynamic behaviour of the tank. Among all the configurations studied here, the most suitable are those fed through a distributor with a centre inlet section in medium flow conditions and fed through a distributor with a lower inlet section in low flow conditions. It can therefore be concluded that a change in the arrangement of feed inlet can allow a device to handle higher volumes by maintaining the flow conditions that improve sedimentation. [Copyright &y& Elsevier]

The present work is concerned with an experimental study of the hydrodynamic damping provided by using vertical baffles in partially filled rectangular tanks. The damping ratio is evaluated for different vertical baffle dimensions, shapes, numbers, and arrangements. A small-scale test rig consisting of a partially filled rectangular tank with a pendulum suspension is designed and constructed to measure the transient responses of the system. The baffles are fitted to attenuate the lateral motion of the liquid slosh. Lower mounted and upper mounted vertical baffles of different heights and numbers are tested. Lower mounted vertical baffles with holes of different sizes and numbers are considered. Finally, the effect of a combination between upper, lower, and holed vertical baffles on the system damping is investigated. The results show that the size and location of the vertical baffles significantly influence the hydrodynamic damping. In general, the damping ratio increases as the tip of the lower mounted baffle plate is close to the liquid free surface and the location of the plate is close to the centre of the tank. Increasing the baffle numbers increases the damping ratio. The upper mounted vertical baffles are more suitable for a chargeable tank. The twin side upper mounted baffles and centre-holed lower mounted baffle arrangements give a maximum damping ratio. [ABSTRACT FROM AUTHOR]