Model in which flow is prescribed by geostrophic balance

[mkrapp]

Hi,

First of all, thank you for Oceananigans.jl. It a fantastic piece of work.

I would like to run a NonhydrostaticModel simulation with a flow with amplitude $U_0$, which should be achieved through forcing with a constant pressure gradient in the y-direction. I want the parcel of ocean to be in geostrophic balance, i.e., $\frac{1}{\rho_O}p_y = −fU_0$, with f=-1.37e-4 in my example.

First, I thought this can be simply achieved using a BackgroundField and passing it as background_fields = (; u = u_bg) but the results don't make sense. Everything seems to move in the y-direction with no effect of Coriolis.

I couldn't find any examples using the pressure fields as forcing/background. Any ideas suggestions?

[glwagner]

Can you be more specific about what you are trying to simulate?

With background_fields = (; u = u_bg), where u_bg is just a positive constant, then you'll simulate a situation in which everything moves to the right at a constant velocity. But this is probably not what you want, because it just amounts to a shift in the frame of reference.

If you impose an initial condition set!(model, u=u0) where u0 is a constant, and you're using coriolis=FPlane(1.0), then you'll obtain an inertial oscillation. Is that what you are looking for?

[mkrapp]

Hey Gregory. That's what I was looking for. 💯 Too obvious, obviously. Thanks heaps!!!