A detached-eddy simulation (DES) model is proposed based on a fully hydrodynamic pressure model instead of hydrostatic model. The numerical scheme is based on finite volume method (FVM) on unstructured grids in the horizontal plane, and σ coordinate in vertical direction to fix free surface and uneven bottom. The in-house codes are paralleled using OpenMP. The proposed model is shown particularly effective in prediction of small-scale vortical structures.