This paper presents a fully integrated coastal process model and a simple parametric cyclonic wind‐pressure model for simulation of wind, storm surges, waves, tidal currents, and river flows. By sharing one computational grid within all those process modules and no need for switching executable codes from one module to another, this full‐coupling feature eliminates possible errors and loss of information due to interpolation and extrapolation of variables between different grids. To generate better cyclonic wind speed and barometric pressure, this parametric wind model includes nonlinear decay effect on wind intensity after hurricane's landfall. By implementing a new wind energy source term, the wave action model is capable of computing wave growth, propagation, and deformation through a regional‐scale domain from deepwater to shallow waters. Model validation and model skill assessment were performed by hindcasting wind, storm surges, waves, and river flows during Hurricane Gustav (2008) by using a high‐resolution grid covering the northern Gulf Coast. With improved wind fields estimated by the new parametric wind model, this fully integrated process model produced high‐quality wavefields in deep and shallow waters and storm tidal levels in the northern Gulf Coasts. Because of computing efficiency provided by seamless integration of process modules and optimized numerical solution schemes, faster‐than‐real‐time predictions of storm surges for the advisories during Hurricane Isaac (2012) were achieved by running the validated model in a desktop computer.

Two-dimensional Reynold Averaged Navier Stokes (RANS) turbulence model simulations for a flow past a square block with Re = 21400 are presented in this paper. An available modified k-ε turbulence model, which is an improved version of the standard k-ε turbulence model, is applied to simulate experiment cases of vortex shedding around a square block. The performance evaluation of the modified model is conducted by assessing its results with the results of the standard k-ε turbulence model based on the similarity with the experiment measurement data. It is found that the modified model improves the drag coefficient by about 16%, the Strouhal number by about 1.5%, and the length recirculation zone by about factor two compared to that of the standard model. The RMSE values indicate a significant improvement of the time averaged velocity along the centre line by about 59% and the velocity profile above the square block by about 6% when the modified model is applied. Generally, the modified k-ε model indicates advantages compared with the standard k-ε model. However, discrepancy is found between the model result and the experiment observation for the free stream velocity at downstream and it may be necessary to consider the 3D effect on turbulent fluctuation in further studies.

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