Numerical simulation of two-dimensional Kelvin-Helmholtz instability using weakly compressible smoothed particle hydrodynamics

2015 ◽  
Vol 78 (5) ◽  
pp. 283-303 ◽  
Author(s):  
Thomas Yue ◽  
Frazer Pearce ◽  
Arno Kruisbrink ◽  
Herve Morvan
2014 ◽  
Vol 553 ◽  
pp. 168-173 ◽  
Author(s):  
Maziar Gholami Korzani ◽  
Sergio Andres Galindo-Torres ◽  
David Williams ◽  
Alexander Scheuermann

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.


2020 ◽  
Vol 59 (40) ◽  
pp. 18236-18246
Author(s):  
Tianwen Dong ◽  
Yadong He ◽  
Jianchun Wu ◽  
Shiyu Jiang ◽  
Xingyuan Huang ◽  
...  

Author(s):  
Steven J. Lind ◽  
Benedict D. Rogers ◽  
Peter K. Stansby

This paper presents a review of the progress of smoothed particle hydrodynamics (SPH) towards high-order converged simulations. As a mesh-free Lagrangian method suitable for complex flows with interfaces and multiple phases, SPH has developed considerably in the past decade. While original applications were in astrophysics, early engineering applications showed the versatility and robustness of the method without emphasis on accuracy and convergence. The early method was of weakly compressible form resulting in noisy pressures due to spurious pressure waves. This was effectively removed in the incompressible (divergence-free) form which followed; since then the weakly compressible form has been advanced, reducing pressure noise. Now numerical convergence studies are standard. While the method is computationally demanding on conventional processors, it is well suited to parallel processing on massively parallel computing and graphics processing units. Applications are diverse and encompass wave–structure interaction, geophysical flows due to landslides, nuclear sludge flows, welding, gearbox flows and many others. In the state of the art, convergence is typically between the first- and second-order theoretical limits. Recent advances are improving convergence to fourth order (and higher) and these will also be outlined. This can be necessary to resolve multi-scale aspects of turbulent flow.


Author(s):  
Samir Hassan Sadek ◽  
Mehmet Yildiz

This work presents the development of both weakly compressible and incompressible Smoothed Particle Hydrodynamics (SPH) models for simulating two-dimensional transient viscoelastic free surface flow which has extensive applications in polymer processing industries. As an illustration with industrial significance, we have chosen to model the extrudate swell of a second-order polymeric fluid. The extrudate or die swell is a phenomenon that takes place during the extrusion of polymeric fluids. When a polymeric fluid is forced through a die to give a polymer its desired shape, due to its viscoelastic non-Newtonian nature, it shows a tendency to swell or contract at the die exit depending on its rheological parameters. The die swell phenomenon is a typical example of a free surface problem where the free surface is formed at the die exit after the polymeric fluid has been extruded. The swelling process leads to an undesired increase in the dimensions of the extrudate. To be able to obtain a near-net shape product, the flow in the extrusion process should be well-understood to shed some light on the important process parameters behind the swelling phenomenon. To this end, a systematic study has been carried out to compare constitutive models proposed in literature for second-order fluids in terms of their ability to capture the physics behind the swelling phenomenon. The effect of various process and rheological parameters on the die swell such as the extrusion velocity, normal stress coefficients, and Reynolds and Deborah numbers have also been investigated. The models developed here can predict both swelling and contraction of the extrudate successfully. The die swell problem was solved for a wide range of Deborah numbers and for two different Re numbers. The numerical model was validated through the solution of fully developed Newtonian and Non-Newtonian viscoelastic flows in a two-dimensional channel, and the results of these two benchmark problems were compared with analytic solutions, and good agreements were obtained.


Sign in / Sign up

Export Citation Format

Share Document