NON-HYDROSTATIC MODELLING OF INFRAGRAVITY WAVES USING SWASH

Dirk Pieter Rijnsdorp, Pieter Bart Smit, Marcel Zijlema

Abstract


This paper presents numerical modelling of the nearshore transformation of infragravity waves induced by bichromatic wave groups over a horizontal and a sloping bottom. The non-hydrostatic model SWASH is assessed by comparing model predictions with analytical solutions over a horizontal bottom and with detailed laboratory observations for a sloping bottom. Good agreement between model predictions and data is found throughout the domain for bound infragravity waves. Furthermore the model predicts greater outgoing free infragravity wave-heights for steeper slope regimes which is consistent with the measurements. The model however tends to overestimate the magnitude of the outgoing infragravity waves.

Keywords


infragravity waves; non-hydrostatic modelling; nearshore wave transformation; SWASH

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