scholarly journals NUMERICAL MODELING OF NON-COHESIVE CONTACT IN MULTI-BODY HYDRODYNAMIC SYSTEMS WITH SPH

2017 ◽  
pp. 49
Author(s):  
Mohammad Javad Mohajeri ◽  
Mehdi Shafieefar ◽  
Soheil Radfar
Keyword(s):  
Boundary Conditions ◽  
Contact Model ◽  
Solid Boundary ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Irregular Case ◽  
Multi Body ◽  
Solid Bodies ◽  
Hydrodynamic Systems

Enforcing solid boundary conditions is one of the most challenging parts of the Smoothed Particle Hydrodynamics (SPH) method and many different approaches have been recently developed. Better understanding of interaction forces between solid bodies is of great importance in the investigation of structural stability and armor layer displacement in breakwaters. In this study, performance of repulsive force and dynamic boundary conditions have been investigated and showed that non-physical results are presented in non-cohesive contact. In this paper, a non-cohesive contact model in multi-body hydrodynamic systems has been developed and validated against other common boundary conditions. Using the developed contact model, the effect of regular and irregular placement of cubic concrete armors has been investigated. Also, comparison has been made with Van Buchem (2009) experimental results and concluded that in the irregular case it is more possible that a unit moves toward instability.

Using an SPH-Based Continuum Representation of Granular Terrain to Simulate the Rover Mobility

2021 ◽  
Author(s):  
Wei Hu ◽  
Jason Zhou ◽  
Radu Serban ◽  
Dan Negrut
Keyword(s):  
Boundary Conditions ◽  
Granular Material ◽  
Smoothed Particle Hydrodynamics ◽  
Continuum Model ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Speed Up

Abstract We use the Smoothed Particle Hydrodynamics (SPH) method to determine the dynamics of granular material in its interaction with a four-wheel rover. The goal of the simulation is to investigate the mobility of the rover while operating on granular terrains. In order to speed up the simulation, we employ a continuum model to capture the dynamics of the deformable terrain. The rover wheel geometry is defined through a mesh. The granular material is modeled as an elasto-plastic continuum that dynamically interacts with the rigid wheels of the rover in a Chrono [1] co-simulation setup. The interaction between each wheel and the granular terrain is handled through so-called Boundary Conditions Enforcing (BCE) particles which are attached to the rover wheel. Several simulations are performed to assess the rover robustness for operation in flat (with obstacles), uphill, downhill, and side-tilted mobility scenarios.

scholarly journals An Application of the Cahn-Hilliard Approach to Smoothed Particle Hydrodynamics

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
M. Hirschler ◽  
M. Huber ◽  
W. Säckel ◽  
P. Kunz ◽  
U. Nieken
Keyword(s):  
Phase Separation ◽  
Boundary Conditions ◽  
Smoothed Particle Hydrodynamics ◽  
Sph Method ◽  
Free Surfaces ◽  
Diffusion Controlled ◽  
Universal Power Law ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Solid Walls

The development of a methodology for the simulation of structure forming processes is highly desirable. The smoothed particle hydrodynamics (SPH) approach provides a respective framework for modeling the self-structuring of complex geometries. In this paper, we describe a diffusion-controlled phase separation process based on the Cahn-Hilliard approach using the SPH method. As a novelty for SPH method, we derive an approximation for a fourth-order derivative and validate it. Since boundary conditions strongly affect the solution of the phase separation model, we apply boundary conditions at free surfaces and solid walls. The results are in good agreement with the universal power law of coarsening and physical theory. It is possible to combine the presented model with existing SPH models.

Numerical Modeling of an Aero-Engine Bearing Chamber Using the Meshless Smoothed Particle Hydrodynamics Method

2015 ◽  
Author(s):  
Lars Wieth ◽  
Christian Lieber ◽  
Wolfram Kurz ◽  
Samuel Braun ◽  
Rainer Koch ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Numerical Method ◽  
Smoothed Particle Hydrodynamics ◽  
Gas Turbines ◽  
Flow Regimes ◽  
Sph Method ◽  
Aero Engine ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Engine Bearing

The prediction of the two-phase flow in an aero-engine bearing chamber using the meshless Lagrangian Smoothed Particle Hydrodynamics (SPH) method is presented in this paper. The prediction of the prevailing flow types, like shear-driven wallfilms, droplet-wall- and droplet-film-interactions require an accurate numerical method, which is robust and efficient. Therefore, a code based on the SPH method was developed and validated to numerically predict such technical relevant multi-phase flows in gas turbines. The simulations to be presented in this paper are focused on an aero-engine bearing chamber configuration, which was experimentally investigated previously. For time saving reasons, the bearing chamber is modeled as two-dimensional problem. This requires special boundary conditions for the oil- and sealing-air flow inlet and outlet, which must physically reflect those of the experiments. In the experiments different operating regimes at different boundary conditions could be identified. The major objective of the simulations is to investigate if those different flow regimes can be captured by the numerical method. The simulations do reproduce the different flow regimes highly accurate and demonstrate the ability of this new approach.

scholarly journals Simulation of Free-Surface Flow Using the Smoothed Particle Hydrodynamics (SPH) Method with Radiation Open Boundary Conditions

2016 ◽  
Vol 33 (11) ◽  
pp. 2435-2460 ◽  
Author(s):  
Xingye Ni ◽  
Jinyu Sheng ◽  
Weibing Feng
Keyword(s):  
Boundary Condition ◽  
Boundary Conditions ◽  
Circulation Model ◽  
Open Boundary ◽  
Open Boundary Conditions ◽  
Open Boundary Condition ◽  
Sph Method ◽  
Open Boundaries ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

AbstractThe smoothed particle hydrodynamics (SPH) technique is a mesh-free numerical method that has great potential to be used in the development of the next generation of numerical ocean models. The implementation of open and solid boundary conditions in the SPH method, however, is not as straightforward as the mesh-based numerical methods. Two types of open boundary conditions are considered in this study: the adaptive open boundary condition (AOBC) and Flather’s open boundary condition (FOBC). These two open boundary conditions are implemented in the SPH-based shallow-water equation (SWE) circulation model for simulating sea surface elevations and depth-mean currents over a limited area with open boundaries. The performance of these two open boundaries is assessed in four numerical test cases. In comparison with the conventional characteristic open boundary condition, both the AOBC and the FOBC allow perturbations to propagate out more effectively and are easy to implement with the specification of external flow conditions at the model open boundaries. The model results also demonstrate that the AOBC requires an accurate estimation of the phase speed of perturbations and could lead to a small drift in the mean water level. By comparison, the FOBC is computationally more efficient without any model drift. The SPH-based SWE circulation model is also used in simulating the laboratory observations of the 1993 Okushiri Tsunami. The numerical results in this case demonstrate the feasibility and capability of the SPH-based SWE model for simulating free-surface flows in regions with complicated bathymetry and irregular coastline.

scholarly journals Numerical Simulation of Non-Homogeneous Viscous Debris-Flows Based on the Smoothed Particle Hydrodynamics (SPH) Method

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2314 ◽  
Author(s):  
Shu Wang ◽  
Anping Shu ◽  
Matteo Rubinato ◽  
Mengyao Wang ◽  
Jiping Qin
Keyword(s):  
Debris Flow ◽  
Water Content ◽  
Smoothed Particle Hydrodynamics ◽  
Debris Flows ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
The Impact ◽  
Kinetic And Potential Energies

Non-homogeneous viscous debris flows are characterized by high density, impact force and destructiveness, and the complexity of the materials they are made of. This has always made these flows challenging to simulate numerically, and to reproduce experimentally debris flow processes. In this study, the formation-movement process of non-homogeneous debris flow under three different soil configurations was simulated numerically by modifying the formulation of collision, friction, and yield stresses for the existing Smoothed Particle Hydrodynamics (SPH) method. The results obtained by applying this modification to the SPH model clearly demonstrated that the configuration where fine and coarse particles are fully mixed, with no specific layering, produces more fluctuations and instability of the debris flow. The kinetic and potential energies of the fluctuating particles calculated for each scenario have been shown to be affected by the water content by focusing on small local areas. Therefore, this study provides a better understanding and new insights regarding intermittent debris flows, and explains the impact of the water content on their formation and movement processes.

Numerical investigation of anguilliform locomotion by the SPH method

2019 ◽  
Vol 30 (1) ◽  
pp. 328-346 ◽  
Author(s):  
Amin Rahmat ◽  
Hossein Nasiri ◽  
Marjan Goodarzi ◽  
Ehsan Heidaryan
Keyword(s):  
Drag Coefficient ◽  
Numerical Investigation ◽  
Sph Method ◽  
Content Type ◽  
Aquatic Locomotion ◽  
Wide Range ◽  
Particle Hydrodynamics ◽  
Dummy Particles ◽  
Smoothed Particle ◽  
Sph Algorithm

Purpose This paper aims to introduce a numerical investigation of aquatic locomotion using the smoothed particle hydrodynamics (SPH) method. Design/methodology/approach To model this problem, a simple improved SPH algorithm is presented that can handle complex geometries using updatable dummy particles. The computational code is validated by solving the flow over a two-dimensional cylinder and comparing its drag coefficient for two different Reynolds numbers with those in the literature. Findings Additionally, the drag coefficient and vortices created behind the aquatic swimmer are quantitatively and qualitatively compared with available credential data. Afterward, the flow over an aquatic swimmer is simulated for a wide range of Reynolds and Strouhal numbers, as well as for the amplitude envelope. Moreover, comprehensive discussions on drag coefficient and vorticity patterns behind the aquatic are made. Originality/value It is found that by increasing both Reynolds and Strouhal numbers separately, the anguilliform motion approaches the self-propulsion condition; however, the vortices show different pattern with these increments.

scholarly journals Progress in the Smoothed Particle Hydrodynamics Method to Simulate and Post-process Numerical Simulations of Annular Airblast Atomizers

2020 ◽  
Vol 105 (4) ◽  
pp. 1119-1147
Author(s):  
G. Chaussonnet ◽  
T. Dauch ◽  
M. Keller ◽  
M. Okraschevski ◽  
C. Ates ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Flux Ratio ◽  
Liquid Sheet ◽  
Sph Method ◽  
Post Process ◽  
Finite Time Lyapunov Exponent ◽  
Fragmentation Spectrum ◽  
Particle Hydrodynamics ◽  
Primary Breakup ◽  
Smoothed Particle

AbstractThis paper illustrates recent progresses in the development of the smoothed particle hydrodynamics (SPH) method to simulate and post-process liquid spray generation. The simulation of a generic annular airblast atomizer is presented, in which a liquid sheet is fragmented by two concentric counter swirling air streams. The accent is put on how the SPH method can bridge the gap between the CAD geometry of a nozzle and its characterization, in terms of spray characteristics and dynamics. In addition, the Lagrangian nature of the SPH method allows to extract additional data to give further insight in the spraying process. First, the sequential breakup events can be tracked from one large liquid blob to very fine stable droplets. This is herein called the tree of fragmentation. From this tree of fragmentation, abstract quantities can be drawn such as the breakup activity and the fragmentation spectrum. Second, the Lagrangian coherent structures in the turbulent flow can be determined easily with the finite-time Lyapunov exponent (FTLE). The extraction of the FTLE is particularly feasible in the SPH framework. Finally, it is pointed out that there is no universal and ultimate non-dimensional number that can characterize airblast primary breakup. Depending on the field of interest, a non-dimensional number (e.g. Weber number) might be more appropriate than another one (e.g. momentum flux ratio) to characterize the regime, and vice versa.

scholarly journals Application of Smoothed Particle Hydrodynamics (SPH) for the Simulation of Flow-like Landslides on 3D Terrains

2022 ◽  
Author(s):  
Binghui Cui ◽  
Liaojun Zhang
Keyword(s):  
Risk Assessment ◽  
Smoothed Particle Hydrodynamics ◽  
Disaster Mitigation ◽  
Sph Method ◽  
Landslide Event ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Simulation Results ◽  
Mitigation Design ◽  
The Impact

Abstract Flow-type landslide is one type of landslide that generally exhibits characteristics of high flow velocities, long jump distances, and poor predictability. Simulation of it facilitates propagation analysis and provides solutions for risk assessment and mitigation design. The smoothed particle hydrodynamics (SPH) method has been successfully applied to the simulation of two-dimensional (2D) and three-dimensional (3D) flow-like landslides. However, the influence of boundary resistance on the whole process of landslide failure is rarely discussed. In this study, a boundary algorithm considering the friction is proposed, and integrated into the boundary condition of the SPH method, and its accuracy is verified. Moreover, the Navier-Stokes equation combined with the non-Newtonian fluid rheology model was utilized to solve the dynamic behavior of the flow-like landslide. To verify its performance, the Shuicheng landslide event, which occurred in Guizhou, China, was taken as a case study. In the 2D simulation, a sensitivity analysis was conducted, and the results showed that the shearing strength parameters have more influence on the computation accuracy in comparison with the coefficient of viscosity. Afterwards, the dynamic characteristics of the landslide, such as the velocity and the impact area, were analyzed in the 3D simulation. The simulation results are in good agreement with the field investigations. The simulation results demonstrate that the SPH method performs well in reproducing the landslide process, and facilitates the analysis of landslide characteristics as well as the affected areas, which provides a scientific basis for conducting the risk assessment and disaster mitigation design.

Smoothed Particle Hydrodynamics into the Fluid Dynamics of Classical Problems

2016 ◽  
Vol 846 ◽  
pp. 73-78 ◽  
Author(s):  
Maziar Gholami Korzani ◽  
S. Galindo Torres ◽  
Alexander Scheuermann ◽  
David J. Williams
Keyword(s):  
Fluid Dynamics ◽  
Analytical Solutions ◽  
Poiseuille Flow ◽  
Smoothed Particle Hydrodynamics ◽  
Slip Boundary Condition ◽  
Sph Method ◽  
Slip Boundary ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Computational Fluid Dynamics Cfd

The study concerns the application of the Smoothed Particle Hydrodynamics (SPH) method within the computational fluid dynamics (CFD). In the present study, some classical problems – the Poiseuille flow, the Hagen-Poiseuille flow, and the Couette flow – with the analytical solutions were investigated to verify a newly developed code of SPH. The code used for solving these problems, is an entirely parallel SPH solver in 3D and has been developed by the authors. Fluid was modelled as a viscous liquid with weak compressibility. The boundary walls were simulated with a special set of fixed boundary particles, and no-slip boundary condition was considered. Computational results were compared to available analytical solutions for transient hydraulic processes. Good agreement is achieved for the whole transient stage of the considered problems until steady state is reached. The results of this study highlight the potential of SPH to tackle a broad range of problems in fluid mechanics.

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