Volume Increase

jacobva

I am working on a 2D simulation of a wave tank with a rotary paddle wave maker at one end. The paddle stops moving and the fluid is allowed to come to rest before the simulation ends. The issue I'm having is that I appear to have a larger volume of water at the end of the simulation than at the start. The fluid particles are much higher and more spread out and the points height values are also higher but not to the same extent. I'm measuring the free surface with the default value of 40% of the reference mass but I don't understand why the particles are spreading out in this manner to increase my free surface height.

Does anybody have any idea what is happening?

Thanks

Jacob

Alex

That is strange... what is the speed of sound you are using (cteB also controls compressibility of the fluid??? are you using deltaSPH??

Regards

jacobva

Hi Alex,

I've used a range of sound coefficients and get the same problem each time. My cteB value is 8404.57 which is a lot lower than other values I've seen online so maybe this is the problem. I'm not sure what it is or how to change it though. I'm using a value of 0.1 for DeltaSPH.

Thanks

Jacob

patjon

Hey Jacob,

I have seen similar tendencies with the DeltaSPH correction, especially when the simulated time is relatively long (>50s). I used the simpler Shepard-filter density-correction instead and observed less volume increase.

/ Patrick