Computation of the Force with mesh deformation
 

Hello everyone,

I have been trying to simulate the oscillation of a box, to compute oscillatory hydrodynamic coefficient.
For that, I use a mesh deformation, that is, the box is oscillating in calm water.
Normally, I would expect a sinusoidal force result in the direction of motion (thus I would compute hydrodynamic coefficients from Morison force equation).
However, I get very noisy results. When I try to reduce this supposedly numerical noise by increasing the timestep, the sinusoid is deformed and results are messy.
I precise that I alternatively used both SST and SAS turbulence models and the simulation is run with parallel recursive coord bisection (Metis failed).
Can anyone provide some insights to resolve this troubling issue ?

Thank you in advance

I assume nobody has encountered this issue before ?

Your initial question was unclear so I did not bother replying. Sorry to be cruel but with some many posts on-line I rather spend my time on better written questions.

Can you post an image of what you are seeing, some plots of what is "messy", and some images of your geometry so we know what you are talking about.

Are you using slight incompressible water for water material properties?