SUMMARYThis paper describes a method for simulation of viscous flows with a free surface around realistic hull forms with a transom, which has been developed based on a FINFLO RANS solver with a moving mesh. A dry-transom model is proposed and implemented for the treatment of flows off the transom. The bulk RANS flow with the artificial compressibility is solved by a cell-centred finite volume multigrid scheme and the free surface deformed by wave motions is tracked by satisfying the kinematic and dynamic free-surface boundary conditions on the actual location of the surface. The effects of turbulence on flows are evaluated with the Baldwin-Lomax turbulence model without a wall function. A test case is modern container ship model with a transom, the Hamburg Test Case. The calculated results are validated and they agree well with the measured results in terms of the free-surface waves and the total resistance coefficient. Furthermore, the numerical solutions successfully captured many important features of the complicated interaction of the free surface with viscous flows around transom stern ships. In addition, the convergence performance and the grid refinement studies are also investigated.

SUMMARYAn algebraic procedure for grid orthogonalization has been developed. It is often difficult to include both grid clustering and orthogonalization in a grid generation method. Often the degree and extent of orthogonality are hard to control when orthogonalization is included in a complicated grid generation method. Fortunately, grid orthogonalization can be performed independently of grid generation. The orthogonalization method developed is simple and includes invertibility control.

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