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

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.

Automated summary

In this study, a series of benchmark test cases were selected to evaluate and compare coupled model frameworks for wave-current interaction. Calibration uncertainties were identified and highlighted through comparing calibrated and default parameter settings. The calibrated model results showed good correlation with experimental and analytical data, as well as benchmarked predictions from other wave-current models.