Free surface flow simulation around a Wigley hull using viscous and potential flow approaches

Abstract

The incompressible free surface flow around a Wigley hull form has been simulated using a commercial RANSE code using the two-phase Eulerian-Eulerian fluid approach, and a potential flow code using on the Rankine source method. The flow has been simulated around the hull at two Froude numbers and comparisons between the results and the experimental results have been made. Two turbulence models (k-ε and Shear Stress Transport) are used in the commercial RANSE code. The computational grid in the commercial code has been used for generating the unstructured tetrahedral and structured hexahedral computational grid required for the RANSE code solver. The potential flow code uses quadrilateral structured patches to mesh both the ship hull surface and the water surface around the hull. In all the simulations, the hull is fixed. The results compare well with the available experimental data. the theoretical prediction of waves around simple bodies, or ship hulls of simplified analytical lines (Wehausen, 1973). The Boundary Element Method (BEM), which is well known as " panel method " is widely used since the works of Hess and Smith (1964) and Dawson (1977) for predicting wave patterns around ships hulls. In this method, the inviscid, irrotational fluid is considered, and with the aid of panel methods for discretization, the flow is computed by solving the Laplace equation. Triangular or quadrilateral panels are used for approximating the surface of the ship. The Rankine source method (Gatchell et al., 2001; Jensen & Soding, 1986; Larson et al., 1989) is the most widely used technique for ship wave resistance simulation problems. The discretization process in this case is made for both body surface and free water surface. The free surface boundary condition can be incorporated successfully in the simulation process based on a so-called double model solution, which was proposed by Dawson (1977). Since then it has been widely applied as a practical method and many improvements have been made to account for the nonlinearity of the free surface physics.