Numerical dissipation (non-linear wave fsi)
ncsalis opened this issue · comments
Results are significantly worsened when simulating the case with high particle resolution (dx=0.015 circa 8M particles). This did not happened before merge #274 (prevented free surface rising when simulating with low particle resolution). Maybe it's better to revert this change since also @Shuaihao-Zhang encountered problems after this.
Snapshot of the wave-structure impact before #274 and after
It really increases the numerical dissipation of the simulation. We probably can decrease the numerical dissipation, as a first check. As the present limiting parameter is based on previous formulation.
I will check the limiter in the following days. I have found this issue also in the 2d_nlwfsi case, the numerical dissipation is quite high even at low particle resolutions.
#324 is ineffective, with lower limiter the free surface elevation does not improve. Also the dynamics (wave phase) of the wave is significantly modified and this aspect is unchanged
So the new formulation is OK?
Yes, the new formulation is ok
For numerical dissipation, Yaru's work will be much helpful.
https://arxiv.org/abs/2304.14865
I made another small change, but the result is similar.
Thank you for the suggestion on Yaru's paper. I also was thinking that first order consistency should improve the result
The first order consistency correction works very well. Result is now marginally improved
With the KGC seems that there is low dissipation thus with higher wave height that leads to higher amplitude of the fsi. How increase dissipation? I have tried by modifying the alpha parameter in the WKGC formulation but it doesn't produce significant result.
Ok, thank you!