Oscillation in pressure- 2d hydrostatic tank- how to remove?

prasanna

Hi all,

I'm trying to simulate the 2d hydrostatic tank case. I found that the pressure field oscillates about the correct value. for example, if the pressure at a point should be 10 it oscillates between 0 and 20 like a sine wave. it looks like some kind of numerical instability. if this issue is already found, can anybody suggest materials in the literature(i tried but still unclear) that explains it?. What is the possible remedy if any has been found.? Or could it be something wrong in coding?

Alex

That issue is due to the boundary condition implemented in DualSPHysics; the so called DBCs. These boundary particles modify the value of density/pressure following continuity equation when interacting with fluid particles. Those oscillations can be reduced at a certain range increasing the resolution. However for a still water case, the oscillation dissapear after a while.
New boundary conditions are being implemented in the code such as the so-called Boundary Integrals.

Regards

prasanna

Thank you Alex for the reply. Is there any other remedy for the problem apart from increasing the resolution? since Sph needs lots of tuning is there any parameter which can minimize the amplitude of the oscillation?

amir

Hi Alex
Would you please give me a reference, which introduces "Boundary Integrals" for SPH?
Thanks

Alex

https://wiki.manchester.ac.uk/spheric/index.php/SPH_Theory_Working_Group#GC.233:_Boundary_conditions

M. Ferrand, D. R. Laurence, B. D. Rogers, D. Violeau, and C. Kassiotis. Unified semi-analytical wall boundary conditions for inviscid, laminar or turbulent flows in the meshless SPH method. International Journal for Numerical Methods in Fluids, 71(4):446–472, 2013. ISSN 1097-0363. doi:10.1002/fld.3666. URL http://dx.doi.org/10.1002/fld.3666.