A novel non-reflecting boundary condition for fluid dynamics solved by smoothed particle hydrodynamics

2018 ◽  
Vol 860 ◽  
pp. 81-114 ◽  
Author(s):  
Pingping Wang ◽  
A-Man Zhang ◽  
Furen Ming ◽  
Pengnan Sun ◽  
Han Cheng
Keyword(s):  
Fluid Dynamics ◽  
Smoothed Particle Hydrodynamics ◽  
High Speed ◽  
Computational Domain ◽  
Infinite Domain ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Broad Variety ◽  
Pass Through ◽  
The Time Domain

Non-reflecting boundary conditions (NRBCs) play an important role in computational fluid dynamics (CFD). A novel NRBC based on the method of characteristics using timeline interpolations is proposed for fluid dynamics solved by smoothed particle hydrodynamics (SPH). It is performed by four layers of particles whose pressures and velocities are obtained through the Lagrange interpolation in the time domain which is derived from the propagation of characteristic waves between particles. The proposed NRBC can allow outward travelling pressure and velocity messages to pass through the boundary without obvious reflection. That is, with the implementation of the NRBC, the solution in a finite computational domain of interest is close to that in an infinite domain. Several numerical tests show that this NRBC is robust and applicable for a broad variety of hydrodynamics ranging from low to high speed.

Numerical modelling of oil distribution and churning gear power losses of gearboxes by smoothed particle hydrodynamics

2018 ◽  
Vol 233 (1) ◽  
pp. 74-86 ◽  
Author(s):  
Hua Liu ◽  
Ghaith Arfaoui ◽  
Milos Stanic ◽  
Laurent Montigny ◽  
Thomas Jurkschat ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Smoothed Particle Hydrodynamics ◽  
High Speed ◽  
Operational Reliability ◽  
Power Losses ◽  
Oil Distribution ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Smoothed Particle Hydrodynamics Method

Sufficient oil supply of all machine elements in gearboxes is usually required to avoid damage during operation. Quite frequently, transmissions are conservatively designed with an oversupply of oil to guarantee operational reliability. An oversupply of oil results in an unnecessarily high amount of oil being kept in motion, which in turn leads to excessive hydraulic gear power losses. In high-speed gearboxes in particular, churning losses can contribute greatly to the total power losses. Further detailed information on the oil distribution in gearboxes is needed in order to increase the efficiency and operational reliability of gearboxes. Computational Fluid Dynamics methods provide a flexible way of investigating oil behaviour in transmissions with almost no restrictions regarding geometry and operating conditions. Generally, there are two main methods of computational fluid dynamics simulation in gearboxes: the traditional finite-volume based method (Eulerian approach) and the mesh-free particle-based method (Lagrangian approach). In this work, a computational fluid dynamics model based on the particle-based smoothed particle hydrodynamics method is built to investigate the oil distribution and churning losses of a dip-lubricated single stage gearbox on an efficiency gear test rig. Results are shown and discussed for different rotational speeds and oil temperatures. The smoothed particle hydrodynamics method provides a high potential of predicting the oil distribution of modern dip-lubricated transmission systems. Comparisons with high-speed camera recordings show good agreement. However, the method shows a need for improvement in churning loss prediction.

Modeling Hypervelocity Impacts Using Smoothed Particle Hydrodynamics

2018 ◽  
Author(s):  
M. Ganser ◽  
B. van der Linden ◽  
C. G. Giannopapa
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Large Deformations ◽  
Hypervelocity Impact ◽  
Density Fluctuations ◽  
Computational Domain ◽  
Simulation Tool ◽  
Hypervelocity Impacts ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

Hypervelocity impacts occur in outer space where debris and micrometeorites with a velocity of 2 km/s endanger spacecraft and satellites. A proper shield design, e.g. a laminated structure, is necessary to increase the protection capabilities. High velocities result in massive damages. The resulting large deformations can hardly be tackled with mesh based discretization methods. Smoothed Particle Hydrodynamics (SPH), a Lagrangian meshless scheme, can resolve large topological changes whereas it still follows the continuous formulation. Derived by variational principles, SPH is able to capture large density fluctuations associated with hypervelocity impacts correctly. Although the impact region is locally limited, a much bigger domain has to be discretized because of strong outgoing pressure waves. A truncation of the computational domain is preferable to save computational power, but this leads to artificial reflections which influence the real physics. In this paper, hypervelocity impact (HVI) is modelled by means of basic conservation assumptions leading to the Euler equations of fluid dynamics accompanied by the Mie-Grueneisen equation of state. The newly developed simulation tool SPHlab presented in this work utilizes the discretization method smoothed particle hydrodynamics (SPH) to capture large deformations. The model is validated through a number of test cases. Different approaches are presented for non-reflecting boundaries in order to tackle artificial reflections on a computational truncated domain. To simulate an HVI, the leading continuous equations are derived and the simulation tool SPHlab is developed. The method of characteristics allows to define proper boundary fluxes by removing the inwards travelling information. One- and two-dimensional model problems are examined which show excellent absorption behaviour. An hypervelocity impact into a laminated shield is simulated and analysed and a simple damage model is introduced to model a spallation failure mode.

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.

SPHERA v.9.0.0: A Computational Fluid Dynamics research code, based on the Smoothed Particle Hydrodynamics mesh-less method

2020 ◽  
Vol 250 ◽  
pp. 107157 ◽  
Author(s):  
Andrea Amicarelli ◽  
Sauro Manenti ◽  
Raffaele Albano ◽  
Giordano Agate ◽  
Marco Paggi ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Smoothed Particle Hydrodynamics ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Mesh Less

scholarly journals GPU Accelerated Particle-based Computational Acoustics Solving Based on SPH

2017 ◽  
Author(s):  
Linxu Fan ◽  
Yongou Zhang ◽  
Chizhong Wang ◽  
Tao Zhang
Keyword(s):  
Fluid Dynamics ◽  
Wave Equation ◽  
Smoothed Particle Hydrodynamics ◽  
Search Method ◽  
Two Dimensional ◽  
Linked List ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Dynamics Problems ◽  
Dimensional Domain

Smoothed particle hydrodynamics (SPH) is regarded as a pure Lagrangian approach, which can solve fluid dynamics problems without the creation of mesh. In this paper, a paralleled SPH solver is developed to solve particle-based computational acoustics (PCA). The aim of this paper is to study the feasibility of using SPH to solve acoustic problems and to improve the efficiency of solving processes by paralleling some procedures on GPU during calculating. A stand SPH code running serially in a CPU is proposed to solve wave equation. This is a wave propagating in a two-dimensional domain. After finishing the computation, the results are compared with the theoretical solutions and they agree well. So its feasibility is verified. There are two main methods for searching neighbor particles: all-pair search method and linked-list search method. Both methods are used in different codes to simulate an identical problem and their runtimes are compared to investigate their searching efficiencies. The runtime results show that linked-list search method has a higher efficiency, which can save a lot of searching time when simulating problems with huge amounts of particles. Furthermore, the percentages of different procedures’ runtimes in a simulation are also discussed to find the most consuming one. Then, some codes are modified to run in different GPUs and their runtimes are compared with those of serial ones on a CPU. Runtime results show that the paralleled algorithm can be more than 80 times faster than the serial one. The result shows that GPU paralleled SPH computing can achieve desirable accuracy and speed in solving acoustic problems.

Introduction: DSFD 2013 in Yerevan, Armenia

2014 ◽  
Vol 25 (12) ◽  
pp. 1402001
Author(s):  
Bruce Boghosian
Keyword(s):  
Fluid Dynamics ◽  
Smoothed Particle Hydrodynamics ◽  
Lattice Boltzmann ◽  
Lattice Gas ◽  
American University ◽  
Discrete Simulation ◽  
International Conference ◽  
Particle Hydrodynamics ◽  
Lattice Gas Models ◽  
Smoothed Particle

The 22nd international conference on the Discrete Simulation of Fluid Dynamics (DSFD 2013) was held on the campus of the American University of Armenia in Yerevan, Armenia on 15–19 July 2013. Approximately 60 participants took part in the conference, with discussions ranging from lattice Boltzmann and lattice-gas models of fluids, to smoothed-particle hydrodynamics and stochastic rotation dynamics. The conference presented a unique opportunity for communities of computational fluid dynamicists from the region to share their research with each other, and with an audience of some of the world's leading experts in the field.

A Simulation of Domain Decomposition Method for Smoothed Particle Hydrodynamics

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Taehyo Park ◽  
Shengjie Li ◽  
Mina Lee ◽  
Moonho Tak
Keyword(s):  
Parallel Computing ◽  
Smoothed Particle Hydrodynamics ◽  
Message Passing ◽  
Message Passing Interface ◽  
Domain Decomposition Method ◽  
Computational Domain ◽  
Sph Method ◽  
Multiple Data ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

Nowadays, the numerical method has become a very important approach for solving complex problems in engineering and science. Some grid-based methods such as the finite difference method (FDM) and finite element method (FEM) have already been widely applied to various areas; however, they still suffer from inherent difficulties which limit their applications to many problems. Therefore, a strong interest is focused on the meshfree methods such as smoothed particle hydrodynamics (SPH) to simulate fluid flow recently due to the advantages in dealing with some complicated problems. In the SPH method, a great number of particles will be used because the whole domain is represented by a set of arbitrarily distributed particles. To improve the numerical efficiency, parallelization using message-passing interface (MPI) is applied to the problems with the large computational domain. In parallel computing, the whole domain is decomposed by the parallel method for continuity of subdomain boundary under the single instruction multiple data (SIMD) and also based on the procedure of the SPH computations. In this work, a new scheme of parallel computing is employed into the SPH method to analyze SPH particle fluid. In this scheme, the whole domain is decomposed into subdomains under the SIMD process and it composes the boundary conditions to the interface particles which will improve the detection of neighbor particles near the boundary. With the method of parallel computing, the SPH method is to be more flexible and perform better.

Numerical Simulation of Tank Discharge Using Smoothed Particle Hydrodynamics

2014 ◽  
Vol 553 ◽  
pp. 168-173 ◽  
Author(s):  
Maziar Gholami Korzani ◽  
Sergio Andres Galindo-Torres ◽  
David Williams ◽  
Alexander Scheuermann
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Smoothed Particle Hydrodynamics ◽  
Two Dimensional ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Stream Lines ◽  
Good Agreement

The study concerns the application of the smoothed particle hydrodynamics (SPH) method within computational fluid dynamics. In the present study, a tank discharge with a falling head is investigated. Water is modelled as a viscous fluid with weak compressibility. An enhanced treatment of the solid boundaries is used within the two-dimensional SPH scheme. The boundaries are represented by a special set of SPH particles that differ from the ones representing the fluid by being immovable, preventing the fluid from leaving the container. Particles with different colors are used to illustrate the sequence of the empting the tank as well as the velocity vectors to show stream lines. A code is developed using C++ to solve all equations explicitly by use of a Verlet algorithm. Results are compared to an analytical solution, and a good agreement is achieved.

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