Benchmarking a two-way coupled coastal wave–current hydrodynamics model

Elsevier, Ocean Modelling, Volume 183, June 2023
Fragkou A.K., Old C., Venugopal V., Angeloudis A.

Wave–current interaction phenomena are often represented through coupled model frameworks in ocean modelling. However, benchmarking of these models is scarce, revealing a substantial research challenge. We seek to address this through a selection of cases for coupled wave–current interaction modelling. This comprises a series of analytical and experimental test cases spanning three diverse conditions of wave run-up, one scenario of waves opposing a current flow, and a 2-D arrangement of waves propagating over a submerged bar. We simulate these through coupling the spectral wave model, Simulating WAves Nearshore (SWAN), with the coastal hydrodynamics shallow-water equation model, Thetis, using the Basic Model Interface (BMI) structure. By comparing calibrated versus default parameter settings we identify and highlight calibration uncertainties that emerge across a range of potential applications. Calibrated model results exhibit good correlation against experimental and analytical data, alongside benchmarked wave–current model predictions, where available. Specifically, inter-model comparisons show equivalent accuracy. Finally, the coupled model we developed as part of this work showcases its ability to account for wave–current effects, in a manner extensible to other coupled processes through BMI and applicable to more complex geometries.