GitHub

Model API

Ripple depends directly on Oceananigans and follows Oceananigans and Breeze conventions for optional model components: absent advection, sources, and coupling are represented by nothing.

Semantics Contract

  • advection=nothing means no phase-space transport is applied.
  • advection=Centered(), advection=UpwindBiased(), advection=WENO(), or advection=FluxFormAdvection(...) uses Oceananigans tracer advection for horizontal transport of every spectral bin.
  • sources=nothing means no source tendency is applied.
  • coupling=nothing means no current-coupling update is applied.
  • SourceTermSet(), NoSource(), and NoCurrentCoupling() are compatibility inputs and normalize to nothing.
  • With all optional dynamics absent, time_step! advances the clock and leaves the action field unchanged.
  • The CFL diagnostic is zero when advection=nothing and uses the active transport velocities otherwise.

Ripple no longer provides HamiltonianFiniteVolume, Hamiltonian velocity operators, a Simulation type, or diagnostic/output writer types. Transport is routed through Oceananigans advection machinery.

Product Fields

ProductField stores data over horizontal physical space and coordinate space without flattening the spectrum. A wave-action field is indexed as N[i, j, m, n], where i, j address physical cells and m, n address spectral cells.

Primary constructors and helpers:

  • RectilinearGrid
  • WaveActionField(grid, spectral_grid)
  • ProductField
  • physical_grid(field)
  • coordinate_grid(field)
  • product_grid(field)

Physical Grid

RectilinearGrid carries x, y, and z coordinates. The vertical coordinate is part of the physical grid and is used directly by CWCM Q transforms:

grid = RectilinearGrid(CPU();
                       size=(8, 4, 16),
                       x=(0, 8),
                       y=(0, 4),
                       z=(-1, 0))
qtransform = QTransform(QKernel(Float64), grid)

Spectral Grids

Available spectral grids:

  • CartesianWaveVectorGrid
  • PolarWaveVectorGrid
  • FrequencyDirectionGrid

Spectral integrals use exact finite-volume cell measures through spectral_cell_measure, spectral_cell_measures, and integrate_spectrum.

Coupling

CWCM coupling uses matrix-free QTransform operators based on the physical grid's vertical faces. Use QKernel, QTransform, CWCMPrescribedCurrentCoupling, compute_doppler_velocity!, and pseudomomentum helpers to connect wave action to current-coupling diagnostics.