How to get z-coordinate in discrete forcing term?

[Leezhard]

Hi all,

I encountered a basic problem but I cannot manage to overcome it. I am using the discrete forcing term in the following way:

function forcing_func(i, j, k, grid, clock, model_fields)
    @inbounds begin
        dτxzdx = (-model_fields.τxz[i+2,j,k] + 8*model_fields.τxz[i+1,j,k] - 8*model_fields.τxz[i-1,j,k] +   model_fields.τxz[i-2,j,k]) / (12 * dx)
        dτzzdz = (-model_fields.τzz[i,j,k+2] + 8*model_fields.τzz[i,j,k+1] - 8*model_fields.τzz[i,j,k-1] +   model_fields.τzz[i,j,k-2]) / (12 * dz)
        buoyancy = Ri*model_fields.ρ[i,j,k]
        return (1-β)/Re * (dτxzdx + dτzzdz) + buoyancy # + Ri/2 *(z + 1), I want to add this extra term
    end
end

The code currently works, but now I want to add an extra term: Ri/2 * (z + 1). I have noticed that znodes may help, but I can not find such an example using it to get z-coordinate with k-index in the discrete forcing term.

Many thanks in advance.

[ali-ramadhan]

Hi @Leezhard! I think you're looking for the znode function defined here for example:

Oceananigans.jl/src/Grids/vertical_discretization.jl

Lines 128 to 129 in a84b3f8

	@inline znode(k, grid, ℓz) = rnode(k, grid, ℓz)
	@inline znode(i, j, k, grid, ℓx, ℓy, ℓz) = rnode(i, j, k, grid, ℓx, ℓy, ℓz)

where ℓz is the location in the z-direction, e.g. Face() or Center().

It's not exported so you'll have to do using Oceananigans.Grids: znode but then you can use it in forcing functions.