General question regarding regular waves in a wave tank.
 

Hi there,

I have a general question regarding regular waves in a wave tank.

To begin with, I set up a case to run regular waves down a wave tank. I have an inlet relaxation zone and and outlet relaxation zone which are both 1.5 * L (wavelength). The tank itself is approximately 5 * L (and about L/2 wide). I then have regular waves with H = 0.1, depth = 0.4, period = 4 sec generated.

Originally, I was careless with the mesh and had a max aspect ratio > 4. I fixed this and made the mesh so that the aspect ratio is always around 1. To do this, I decreased the number of cells in the vertical direction. I ran the case originally with the poor mesh and while the solution "looked" correct, the velocities seem to be higher than expected. However, when I run the case on the improved mesh (and 40 cells per wavelength, finer than the original run), the solution appears correct up until approximately 10 seconds, at which point it appears that the solution "breaks down".

I realise this is a general question but I am looking for advice on how to improve my solution using waveFoam and I'd like to understand better what might be causing this. I have attached two images: one showing an earlier time step where the solution looks ok.

Thank you for any advice, I am new to CFD and teaching myself so sometimes the basics are difficult to understand!