SPH fluid simulation test: surface tension effects.

With this video I want to show the importance of the surface tension in free surface fluid simulation using typical dam breaking test.

The left video shows a fluid with water properties including surface tension and the right one shows the same fluid without surface tension (blob formation vs. disintegration). The color indicate the speed module (scaled to the max) using jet color map (extracted from matlab). The surface tension model is a "spring-like"(Hook Law using attractive and repulsive forces at same time) force affecting to the free surface particles only.

The code is a modification of SPH (named XSPH) using 2900 particles (for each simulation), and was programmed in Python-Pylab-Pygame.The animation was built in slow camera mode (1/5) and the two videos was joined using blender (Anybody known other free software to do that?)

Category:

Science & Technology

Tags:

• SPH
• test
• simulation
• fluid
• particles
• dam
• breaking
• surface
• tension

[NionsChannel]

Do I get this right? Only the particles on the outside are affected by forces from their neighboors and every other particle is only affected by pressure to avoid compressability?

[jahkr]

Not exactly, the particles inside the fluid are affected by differents forces, like pressure gradient and viscosity (calculated using the neighboors) , but only the particles in the surface are afected by the surface tension (calculated using free surface neighboors only)

[kotsoft]

just curious. what does xsph add to sph, and where can i find more information about this?

[jahkr]

Hi kotsoft, before nothing I want to say that your codes and videos are impressive, congratulations for your work. The XSPH add a equation to basic SPH code to correct the speed of the particles, avoiding "evaporation" effects and improving the numerical stability. The correction is a "simple" average using the neighbors inner to the kernel for each particle. Search this article for more information Simulations of planet-disc interactions using Smoothed Particle Hydrodynamics

[ajcc103]

Hi Jahkr, what algorithm do you use for finding the free surface!? V. interested!!!

[ajcc103]

hi jahkr, what algorithm do you use for finding the free surface?? very interested!!

[Garfulon]

My goal for my life i sto make a game which is the most realistic...simulating every-day life...I just found my water simulator

:)

[trimtrim1980]

How you compute the surface tension and the direction of the surface tension force?

[Weatherlawyer]

Got one of Newton's Cradle for comparison?