André Palóczy

Just found this issue while setting up a `ShallowWaterModel` experiment with nonzero `bathymetry`. Implementing this involves modifying `src/Models/ShallowWaterModels/solution_and_tracer_tendencies.jl` to include the terms associated with bathymetric gradients in `x_pressure_gradient` and `y_pressure_gradient`,...

Thanks @glwagner and @francispoulin, I will give this a try and ping you both along the way. @francispoulin, I feel that having the free surface elevation rather than total height...

@glwagner: > I'm still not sure we want to analytically integrate one of the pressure gradient terms `h dx(h) = dx(h^2/2)` but leave the other unchanged. If we treat them...

Also one thing that is important to get right in multi-layer shallow water models is layer-wise conservation of mass and other properties (see _e.g._, https://aronnax.readthedocs.io/en/latest/verification.html and http://www.nordet.net/beom.html). > Topography that...

That sounds good and it would fix the linear slope cases, but would leave out other idealized topographies such as `h = cos(x)cos(y)`. Although I suppose the error in computing...

Right, I checked the maximum absolute differences for the derivatives of `h = cos(x)cos(y)` with N = 64, 128, 256, 512, 1024, and they are O(1e-14) or O(1e-13).

In `HydrostaticFreeSurfaceModel`: `free_surface.η` -> `free_surface.eta`.

Just found this issue. Thank you for developing DOLfYN! @jessecusack, @jmcvey3, I started implementing bin-mapping following [Dewey & Stringer (2007)](http://dx.doi.org/10.13140/RG.2.1.1042.8002)'s Equation B1 [here](https://github.com/apaloczy/dewaveADCP/blob/894c836ecf1e248135c17fdcae418d5ee238d0cd/dewaveADCP/beam2earth.py#L430) a while ago. It could use more...