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Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) 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.)

Copyright of Light Industry Machinery is the property of Light Industry Machinery Editorial Office 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.)

Traditional computational fluid dynamics(CFD) solver encounters significant computational costs and struggles with simulating fluids due to the inherently high-dimensional and nonlinear properties. To improve the computational efficiency, a framework combining multi-task learning and graph neural networks (GNN) was proposed here, which could predict unsteady flow quickly and efficiently. Firstly, the fluid computational domain's spatial distribution was modeled by unstructured grids. Then, GNN was employed to extract multidimensional spatial features from this distribution. Finally, the aggregation and updating properties of the message passing mechanism were used to simulate the spatio-temporal variation patterns of the fluid. Considering that there were some correlations between different physical fields, a multi-task learning strategy was adopted to learn the variations of multiple physical field parameters in parallel, which could improve the accuracy and generalization of the model. Validation experiments were carried out on a simulation dataset and compared with graph convolutional neural network. The results show that our model has the best prediction results, with a relative decrease of 7. 2% in mean square error (MSE) at 100 steps and 29. 9% at 200 steps. This model also has a large improvement in computational efficiency, and its prediction speed is improved by one to two orders of magnitude compared with the conventional CFD solver, which provides a good solution on real-time prediction. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering 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.)

Objectives: With the rapid development of electric vehicles (EVs), the maximum rotational speed of EV motors has reached up to 20 000 r/min. Precision polishing of gear surfaces after grinding has become a promising method for improving the noise, vibration, and harshness (NVH) performance of EVs. Abrasive Flow Machining (AFM) is one of the key technologies for efficiently polishing complex gear tooth surfaces. Fixture design plays a critical role in achieving process objectives, reducing surface ripple and roughness, and minimizing damage to the tooth surface accuracy. This article addresses the trade-off between selecting physical models and balancing the accuracy and computational cost of simulation results. It analyzes the impact of different simulation models on the results, providing guidance for AFM fixture design and offering practical experience for fixture optimization in AFM gear processing. Methods: Simulations are conducted using media with different viscosities, viscosity models, and flow models, within the simplest and most typical slit model. Fluid pressure distribution, velocity vectors, wall shear, and streamline distribution cloud mapsare analyzed to reflect machining uniformity. Based on the conclusions drawn from slit model simulations, the simplest Newtonian fluid—water—is selected as the medium for AFM gear shaft processing simulations. The focus is on the uniformity of streamline distribution in the machining area to optimize fixture design. Results: The analysis of slit model simulation results reveals that different physical models have varying impacts on the outcomes: (1) The selection of viscosity models decisively affects the pressure distribution of low-viscosity media. The type of viscosity and turbulence models has little impact on pressure distribution, but it significantly affects the velocity vector, wall shear, and streamline distribution within the abrasive cylinder. (2) For low-viscosity media: implementing a non-Newtonian fluid model has a significant impact on the pressure distribution. Different flow models show marked differences only in wall shear force distributions. Various viscosity models yield different cloud map distributions, but they produce numerically similar values. (3) For high-viscosity media: simulations with non-Newtonian and Newtonian fluid models show consistent results. However, different flow models greatly influence the results, while various viscosity models lead to changes in all simulation results, except for pressure distribution and streamlines within the slit. Despite these variations, the streamline distribution in the processing area remains largely unchanged. Based on the consistency of streamline distribution, fixture design optimization for the AFM gear shaft is carried out, successfully achieving the goal of eliminating gear "ghost frequencies". Conclusions: Despite variations in the physical models, the simulation results exhibit similar trends in distribution, enabling consistent streamline distribution in the processing area. For low-viscosity media, a non-Newtonian fluid viscosity model with laminar flow simulation can be used, and the selection of viscosity models can be simplified based on the rheological characteristics of the actual abrasive flow medium. For high-viscosity media, setting appropriate viscosity values and using laminar flow simulation with a Newtonian fluid model yields consistent pressure and streamline distribution in the processing area, similar to adding viscosity and turbulence models. The slit model simulation results and AFM gear shaft processing tests both demonstrate that streamline information derived from simple physical models can significantly assist in AFM fixture design. In cases where the physical properties of the abrasive flow medium are uncertain—especially in complex flow paths prone to divergence—using the simplest Newtonian fluid, such as water, with laminar flow simulation can provide a reasonable streamline distribution in the processing area. This approach aids in the analysis of processing uniformity, significantly reduces simulation difficulty and costs, and accelerates the fixture design cycle, ultimately enhancing optimization efficiency.

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic 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.)

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants Editorial Office 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.)

In order to meet the functional characteristics of the flying wall crawler, the structure of the flying wall crawler is such that the four rotors are not in the same plane but in a longitudinal arrangement when in flight. The CFD (computational fluid dynamics) simulation of the single-rotor flow field was carried out to verify its reliability. On the basis of these simulations, aerodynamic simulations were carried out for different horizontal spacing, different vertical spacing and different rotational speeds of the longitudinal double rotor. The results were then analysed to determine the effect of the horizontal and vertical spacing and the rotational speed on the aerodynamic characteristics of the front and rear rotor blades and the whole system. The simulation results show that the transverse pitch has a large aerodynamic interference between the longitudinal rotor blades, while the axial pitch is relatively small and the degree of interference is related to the rotational speed. It is clear that the conclusions can provide a basis for the rotor layout, rotational speed and feasibility of flying wall climbing robots. [ABSTRACT FROM AUTHOR]

In order to solve the problem that aluminum coating on bolt surface may be uneven in thickness when aluminum paint was used to coat the bolts, the influence of spraying angle on the uniformity of bolt surface coating is researched in this thesis. Nozzles and bolts of the spraying system were modeled and the computational fluid dynamics simulation software Fluent was used to establish the physical model of the gas-liquid two-phase flow of the atomization flow field. DPM model was used to analyze the interaction between the gas phase and the liquid phase in the flow field. Besides, the spray flow fields at different angles were obtained. The thickness of liquid film deposition on the bolt surface was also predicted and the spraying test system was set up. Results of this research were verified with the simulation results. The simulation and experimental results all show that the bolt surface coating is the most uniform when the spraying angle is 30°. [ABSTRACT FROM AUTHOR]

Copyright of South China Fisheries Science is the property of South China Fisheries Science 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.)

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & 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.)

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING 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.)

Copyright of Automobile Technology is the property of Automobile Technology Editorial Office 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.)

Copyright of Chinese Journal of Applied Mechanics is the property of Chinese Journal of Applied Mechanics Editorial Office 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.)

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING 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.)

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University 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.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) 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.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) 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.)

Aiming at the problems of uneven radial force and leakage caused by the high pressure of the double-stage high-pressure internal gear pump, this paper conducts a simulation study on the performance of the double-stage high-pressure internal gear pump based on Fluid simulation. The study found that by increasing the diameter of the suction pipe or increasing the inlet pressure, the cavitation of the suction cavity in the first boost can be effectively controlled; the gap between the crescent plate and the pinion in the double-stage high-pressure internal gear pump, the gap is small, but the oil leakage rate is very high, and the oil leakage can be reduced by adding a floating sleeve or floating side plate; The flow field distribution of the double-stage high-pressure pump is basically unchanged under different pressures. The negative pressure area of the internal field of the double-stage high-pressure pump under different media is different. By setting the static pressure support groove, the unbalanced radial force in the ring gear can be effectively reduced. The research conclusion can provide a theoretical basis for the engineering application of the two-stage high-pressure internal gear pump. [ABSTRACT FROM AUTHOR]

With advancements in modern medical technology, the treatment of rhegmatogenous retinal detachment has been receiving increasing attention. Globally, vitrectomy combined with intraocular silicone oil tamponade has been widely used for rhegmatogenous retinal detachment, and the surgical equipment and technology required are increasingly advanced. In such an operation, it is crucial to understand how to achieve the best therapeutic effect with the minimum amount of silicone oil tamponade so as to reduce surgical complications. Traditional medical methods cannot effectively evaluate the effect of different silicone oil dosages on retinal hole attachment. Aiming at this concern, the current study proposed a silicone oil tamponade simulation method for retinal detachment surgery. Based on physical modeling and computer numerical discretization techniques, the intraocular force and silicone oil filling state were analyzed. Three-dimensional modeling and simulation of the silicone tamponade process were then conducted and visualized to help with medical decision-making. First, the human eyeball and surgical instruments were modeled and sampled to simulate the eyeball state during the operation. Second, based on differences in density, viscosity coefficient, and surface tension between water and silicone oil, the two-phase flow and water‒silicone oil interaction were simulated. Finally, the solid‒liquid interaction model was constructed to assess the movement and injection process of multiphase liquid in the eyeball. The experimental results show that this method can well present the interaction effect of multiphase fluid movement in the eyeball; understand effects such as surface tension, solid–liquid coupling, liquid stratification, and connector effect; and realize the simulation of the silicone oil injection and water drainage processes through the catheter in the intraocular cavity, which provides an effective way to predict the intraocular state after silicone oil filling and assists doctors in the field of operation process planning and effect prediction.

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power 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.)

[Objectives] The oblique water-exit process of a Trans-Media Aerial Underwater Vehicle (TMAUV)is highly non-linear,unsteady and drastic in flow field. Based on the underwater configuration of a TMAUV,the two-dimensional numerical simulation of the process is carried out by using CFD fluid simulation software under the typical conditions.[Methods] The flow field variation characteristics and the load distribution of the vehicle at different stages of the water-exit process were analyzed,and the distribution of flow velocity field at two typical positions and characteristics of hydrodynamic forces acting on the vehicle in case of water-exit at different pitch and attack angles was compared.[Results] The simulation results show that the flow field and load on both sides of the vehicle will change dramatically when it crosses the water-air interface obliquely. The larger the pitch angle is,the smaller the range of the part of flow field under water will be affected,and the larger the impact on the part of flow field crossing and above the water will be. Compared with the case of water-exit at zero angle of attack,the oblique water-exit of the vehicle at an angle of attack will lead to high frequency and large-scale reverse oscillation of the hydrodynamic force acting on the surface and affect the stability of the vehicle when it exits water.[Conclusions] The results in this paper can provide ideas and theoretical reference for the study of water-exit of submarine-launched missiles,navigation of ships,cross-medium of submarines and other topics.

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office 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.)

Copyright of Journal of Computer-Aided Design & Computer Graphics / Jisuanji Fuzhu Sheji Yu Tuxingxue Xuebao is the property of Gai Kan Bian Wei Hui 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.)

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering 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.)

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office 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.)

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics 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.)

The traditional SPH fluid simulation method usually uses fixed particle smooth length for interpolation, which may result in large interpolation errors in some cases. In order to improve the simulation accuracy, this paper established the relationship between the smoothing length of particles and the harmonic mean of neighboring particle densities, and adaptively adjusted the smoothing length of particles. Furthermore, the paper designed the corresponding particle neighbor search scheme and kernel function to solve the problem of force asymmetry. Experiments show that this method effectively reduces the variance of the number of particle neighbors, which solves the problem of large interpolation error caused by fixed support domain of traditional SPH particles, and makes the simulation results closer to physical facts. At the same time, due to improved calculation accuracy, the simulation stability is enhanced, and the physical simulation can be performed with a larger time step to effectively improve the simulation efficiency. Finally, compared with state-of-the-art methods, this method has advantages both in visual quality and simulation speed. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas & Oil is the property of Editorial Department of Natural Gas & Oil 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.)

Copyright of China Sciencepaper is the property of China Sciencepaper 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.)

This paper presents a novel fast neighbor searching method. By using this method,fluid simulation based on smooth particle hydrodynamics(SPH) can be parallelized easily and run on graphic processing unit(GPU) with high efficiency. The neighbor searching method can search two or more kinds of particles,while saving their information in the same background grid. Ghost boundary particles are introduced to improve the accuracy of boundaries,which can enhance the fidelity of the fluid simulation. Experiments show that the proposed method is more efficient than the traditional SPH method based on GPU.

Copyright of Journal of the Tianjin Polytechnic University / Tianjin Gongye Daxue Xuebao is the property of Journal of Tianjin Polytechnic University 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.)

This paper presented an efficient approach based on smoothed particle hydrodynamics(SPH) to simulate incompressible fluids. The proposed method was an extension of the traditional SPH method designed for compressible fluids. It first introduced a new scheme for pressure evaluation to satisfy the incompressibility constraints. Then it discussed novel calculation methods for pressure force and viscosity force. Finally, the results demonstrate that this method is more capable of realistically simulating fluids with near-incompressibility than previous method. [ABSTRACT FROM AUTHOR]

Fluid simulation based on the Smoothed Particle Hydrodynamics (SPH) plays an important role in the virtual reality, but it requires a lot of computing resources. The general methods are difficult to achieve the real-time requirement of fluid simulation based on SPH. The simulation of fluid consists of physical computing, collision detection and rendering and so on. The parallel computing based on GPU can speed up the computing and collision of particles and simulate the motion of fluid in realtime. In order to satisfy the realistic and real-time requirements, a novel fluid simulation method based on CPU-GPU hybrid acceleration is proposed, which consists of computing and rendering. The computing part of fluid simulation is accelerated by GPU, and the rendering part is accelerated by OpenMP running on CPU. The experiments show that the proposed hybrid acceleration method can significantly reduce the computing time in a fluid time step and complete rendering tasks more quickly. [ABSTRACT FROM AUTHOR]

The rotation of turbine at small attack angle is theoretically analyzed in order to obtain the rotation characteristics of a turbine in front of an underwater fuze at small attack angle,and the simulation models and an experimental program are created. On this basis,the turbine speed at flow velocity of 0 m / s ∼ 35 m / s is obtained at 0° and 5°attack angles. For the non-cavitation and the cavitation number from 0. 2 to 1. 0,the corresponding characteristics of the turbine rotation and cavitation at 10m / s are analyzed by comparing the simulation and experimental results at 0° and 5°attack angles. The results show that the simulation and experimental results are basically consistent and well predict the turbine characteristics. Compared with 0°attack angle,the turbine speed at 5° attack angle becomes higher at lower flow velocity and vice versa; under cavitation,the periodical change of original speed signal of turbine disappears at 5°attack angle,and the turbine stalls in the case of lower cavitation number. [ABSTRACT FROM AUTHOR]

Precise fluid dynamics simulation which is a very heavy computation task always demands high level computer devices. So it can only be applied to offline fluid analysis. On the occasion that a fast computation is necessary, a much simplified model is the only choice. Simplified model consumes much less computation power, but can only offer low precision, and cannot integratly reflect real fluid dynamics. Based on the powerful computation capacity of graphic processing unit(GPU), a real-time liquid payload hydrodynamics simulation method useing smoothed particle hydrodynamics(SPH) to model fluid characteristic and fully solved by GPU is presented. As a non-grid computational fluid dynamics method, SPH guarantees the high accuracy of fluid dynamics simulation. Large scale parallel computing optimization for GPU platform dramatically accelerates the simulation speed. Simulation test result indicates that this method is as accurate as OpenFOAM-a famous computational fluid dynamics(CFD) software, more faster than any CPU solver, and well meets the requirements of real-time aircraft simulation system. [ABSTRACT FROM AUTHOR]

For simulating non-Newtonian fluid motion, in this paper a particle-based method is proposed in this paper. Through adding the stress tensor terms into the Navier-Stokes equations and using the essential method of smoothed particle hydrodynamics, a unified model for simulating non-Newtonian fluid is established. The experimental results show that the elasticity and plasticity of the fluid will change with the values of model parameters κ and/μ. The fluid exhibits more obvious plastic flow and weaker elasticity when κ is increased and μ is decreased, conversely, the fluid exhibits stronger elasticity and weaker plasticity when μ is increased and κ is decreased. By extending the Navier-Stokes equations, non-Newtonian fluid with various elastic and plastic characteristics can be simulated realistically by using this model. [ABSTRACT FROM AUTHOR]