Moving boundary numerical surge model

A moving boundary numerical storm surge model has been developed. The model employs the time split explicit finite difference scheme to solve the partial differential equations that govern the propagation of storm surge waves. The water-land interfaces are considered as moving boundaries. Their propagation is determined along with the solution of surge calculations. Numerical experiments with both hypothetical and actual storms over the Gulf of Mexico and the southern coast of Maine indicate that the moving boundary model predicts a considerably lower surge than the fixed boundary model. Surge simulation over the southern coast of Maine confirms the intuitive assertion that the moving boundary and fixed boundary models would yield the same result if the inland slope is very steep. Various values of wind stress coefficient were reported by various investigators. Most of them were obtained by calibrating the simulated storm surge against the measured values. The majority of the calibrations and verifications were performed over coastal areas where the adjacent dry land has a very small or mild slope. All of the studies adopted the fixed boundary model as a tool. Had a moving boundary model been used for calibration in the coastal areas with very mild slope ofmore » adjacent dry land, the wind stress coefficient would have been higher since the physical unreality of a vertically fixed boundary must be compensated for by the wind stress coefficient in calibration with a fixed boundary model. Thus, it is suggested that extensive recalibration of wind stress coefficients with a moving boundary model should be done, in particular, for those cases with flat dry land abutted to the coast-line such as the south Atlantic coast and the Gulf of Mexico.« less