Numerical modelling of tidal flows in complex estuaries including turbulence: an unstructured finite volume solver and experimental validation

In this paper an unstructured finite volume model for quasi-2D tidal flow with wet–dry fronts and turbulence modelling is presented, and applied to the Crouch–Roach estuarine system (Essex, U.K.). Two depth averaged turbulence models, a mixing length model and a k. model, are used in the numerical computations. An additional limiter to the production of turbulence due to bed friction is introduced in order to improve the performance and numerical stability of the model near wet–dry fronts. In addition to a first-order and a second-order schemes, an hybrid second-order/first-order upwind scheme which improves the accuracy of the first-order scheme while maintaining a good numerical stability is used to discretize the convective flux. Numerical results are compared with observed current speed and water level data, with particular reference to the ability of the model to reproduce shallow water tidal harmonics. Copyright 2006 John Wiley & Sons, Ltd