Computation of Incompressible Viscous Flow around a Marine Propeller : 2nd Report : Turbulent Flow Simulation
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概要
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This paper describes a newly-developed CFD (Computational Fluid Dynamics) scheme for the computation of turbulent flow around a marine propeller. Governing equations are Reynolds-averaged Navier-Stokes equations and continuity equation with pseudo-compressibility. Baldwin-Lomax, zero-equation turbulence model was adopted to simulate turbulent flow both at model and full scale Reynolds Number. Those equations are discretized by cell-centered, finite volume and higher-order upwind scheme with global conservation property. The resulted discrete equations are computed by Implicit Approximate Factorization method. The well-conditioned computational grid system around a marine propeller with H-H topology, is generated using algorithm of Implicit Geometrical method. As a validation study, a series of laminar flow computations were carried out to evaluate the effect of the blade surface resolution on the computed thrust coefficient. Consequently, it is found a thrust coefficient tends to approach to the constant value as the grid resolution higher. Using this result, the necessary condition on the grid size of a propeller blade was determined and used for the consecutive turbulent flow simulations. Turbulent flow simulations around two marine propellers. DTRC4119 and SEIUNMARU Conventional Propeller (CP), were made to validate further on accuracy of the present scheme and its availability for future practical use. The thrust and torque coefficients were predicted from 10 to 20% larger than experiment data but good agreement was obtained for the propeller efficiency. Through the quantitative comparison of the computed results on DTRC4119 with LDV experiment data, it is found that the present scheme can predict qualitatively well the several viscous aspects of propeller blade flow, such as tip-vortex generation, roll-up of the blade wake and the global structure of vortical wake. Scale effect on the propeller performance was also investigated by a series of turbulent flow simulations around SEIUNMARU CP. The computed results from laminar to full-scale Reynolds number show the gradual increase of K_T, decrease of K_Q and remarkable improvement of η_0. The mechanism of the scale effect was further discussed by decomposing a thrust coefficient into its pressure and friction component.
- 社団法人日本船舶海洋工学会の論文
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関連論文
- Computation of Incompressible Viscous Flow around a Marine Propeller : 2nd Report : Turbulent Flow Simulation
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