Ocean Modeling Discussion

No, no, no MIX_S_TS! It's a terrible thing to do with a sigma coordinate. Why wouldn't MIX_GEO work? My biggest problems with it involve wetting and drying and realistic bathymetry. I don't know what you are trying. I'm just suggesting trying a shorter timestep so that you can rule out CFL troubles...

Yes, there's a CFL condition. There's also the timescale of damping on the scales you want to damp (2 dx) and the timescale of damping on scales you don't want to damp. A CFL of 1.0 will be unstable. What are you shooting for? But my case can run with the same condition except I use VIS2 and TNU2, ...

kate wrote: ↑Tue Apr 12, 2022 4:39 pm They have different timestep constraints, depending on dx. You could try a shorter timestep to see if it runs.

Is it CFL condition? Or the t<(Δx/pi).^4./v4? I am confused because I get visc4' s value through the latter

kate wrote: ↑Mon Apr 11, 2022 4:51 pm Does it run with TNU2? Is this a new domain? Are you sure you have a small enough timestep?

Thanks, kate!
But it can run with TNU2; the domain is a curve orthogonal grid made by myself; and my dt=90, I think it is small enough.

Dear ROMS user, As a beginner I meet some problem that: firstly I defined smagorinsky option and I want to define VISC4' and TNU4' s value, so I caculate these parameter with the (ΔX./pi).^4./dt. The model is always blow-up in Max speed and Max rho, no matter how I change the value of VISC4 and TNU4...