Wave Effects on the Storm Surge Simulation: A Case Study of Typhoon Khanun

抄録

To study wave effects on storm surge, a depth-averaged 2D numerical model based on the Delft3D-FLOW model was utilized to simulate near-shore hydrodynamic responses to Typhoon Khanun. The Delft3D-WAVE model is coupled dynamically with the FLOW model and the enhanced vertical mixing, mass flux and wave set-up were considered as wave-current interaction in the coupled model. After verifying storm surge wind and pressure formulae of storm surge and optimizing calibration parameters, three numerical tests with different control variables were conducted. Model tests show that wave effects must be considered in numerical simulation. Simulating the flow-wave coupled model showed that wave-induced surge height could be as large as 0.4 m in near-shore areas for Typhoon Khanun. Comparing to its contribution to the peak surge height, wave-induced surge plays a more significant role to total surge height with respect to the time-averaged surge height in storm events. Wave-induced surge (wave setup) is in advance of typhoon propagation and becomes significant even before the typhoon landfall. Model tests demonstrate that the wave effects are driven predominantly by the storm wave, while the boundary wave contribution is rather limited.