Computation of Incompressible Viscous Flow around a Marine Propeller

Abstract

This paper describes an application of CFD (Computational Fluid Dynamics) to the computation of incompressible viscous flow around a marine propeller. High Reynolds-number flow around a marine propeller operating in a uniform flow is simulated using a newly developed CFD scheme, which is based on cell-centered, finite-volume method with global conservation property for mass and momentum flux.Governing equations are full Navier-Stokes equations and continuity equation with pseudo-compressibility, which are written in boundary-fitted curvilinear coordinate system fixed on a propeller blade. For discretization in space, 3rd-order upwind scheme derived from flux-difference splitting method is adopted for convection terms and 2nd-order central difference scheme for viscous terms, respectively. 1st-order Euler implicit scheme is adopted for the time integration and the resulted discretized equations are solved by Implicit Approximate Factorization (IAF) scheme with high efficiency.A series of high Reynolds-number flow computations around a SEIUNMARU conventional propeller are made to show validity and availability of the present scheme as a practical design tool. Through quantitative comparison of the computed results with experimental data for surface pressure distributions, thrust and torque coefficients, it is clearly shown that present scheme can predict a viscous flow around a marine propeller qualitatively well and that several problems, such as open boundary conditions and excessive grid skewness, should be solved in order to improve accuracy of the present scheme.By flow visualization technique using the computed results, some important characteristics of a rotating propeller flow such as the development of boundary layers and separation on a propeller blade, tip vortex generation and a structure of trailing vortices, are found to be well simulated qualitatively by the present scheme, which may be useful tool for the development of the inviscid-flow calculation method.