This dataset contains the MATLAB codes needed to compute the basic state flow over a static sand bank topography as well as the perturbed modes containing flow patterns, sea surface elevation and topography following from a linear stability approach.

The model is forced with an oscillatory depth-averaged flow, representative of the tidal flow over a sand bank.

The solution is obtained by solving the Generalized Eigenvalue Problem posed by the dimensionless momentum, mass balance and Exner equations, and corresponding boundary conditions.

filename 							description
------------------------------------------------------------------------------------------------------
my_perturbation						compute perturbed given a basic state topography and flow
my_basic_state_transformed 			compute the basic state up to first order in gamma (including the 0-order solution, which is analytical)
my_basicstate_transformmed_anygamma	compute the basic state flow over any order in the expansion parameter gamma

see accompanying publication for equations and definitions:
Local characteristics of sand wave patterns are governed by underlying sand bank: A linear stability approach. Portos-Amill, L., Roos, P.C., Schuttelaars, H.M., Hulscher, S.J.M.H. (2025) Submitted.