Simulation of Standing Waves Using ROMS

[yong.liang]

Hi Everyone,

I am trying to simulate standing waves using ROMS in a linearly stratified fluid. The initial conditions I use is free surface elevation and a corresponding nonzero initial velocity field everywhere in the domain(to excite a specific mode of internal waves). The boundaries of the rectangular domain are all walls except the free surface. Can anyone tell me if I can realize this in ROMS? Thanks.

[kate]

I don't see why not. Do you have a case with an analytic solution? You could use the solution to get the initial conditions which are consistent for free surface and velocity. If you turn off rotation, you might be able to find something with zero initial velocity, just set up the zeta and initial density field appropriately. I would start with a 2-D case, no stratification, unless you want to set up internal waves.

[yong.liang]

I am able to simulate my case with ROMS now. But I have not get the correct numerical results that can match the linear analytic solutions. So I started from a simple case: homogeneous fluid(no stratification), rectangular domain(all wall-type lateral boundaries), the initial condition is a free surface elevation only(standing wave amplitude). I used the 3D solver since the 2D version only solves shallow water equation. Then I examined the output but only got good results at the first time step. From the second step, zeta becomes zero all the time. Could anyone help look at what the problems might be? Thanks.

I don't see why not. Do you have a case with an analytic solution? You could use the solution to get the initial conditions which are consistent for free surface and velocity. If you turn off rotation, you might be able to find something with zero initial velocity, just set up the zeta and initial density field appropriately. I would start with a 2-D case, no stratification, unless you want to set up internal waves.

[yong.liang]

I just noticed that Rutgers ROMS is a not a non-hydrostatic model. This does not work for my cases.

[kate]

The French have a team working hard to make ROMS_Agrif have a non-hydrostatic option. Coming soon?

[patrickm]

yes Kate, we have done the TANK test case in the homogeneous and two-layered fluid (internal soliton) using a non-hydrostatic version of ROMS_AGRIF. We can accurately reproduce both the hydrostatic and non-hydrostatic analytical solutions in the homogeneous case and lab experiments in the two-layer case. There is more work needed before we want to release this code (optimization, realistic cases capability ...), but that will not be too long, hopefully before the end of the year ...