Unsteady Viscous Flow Simulation around the Blade of Rowing Boat〔含討論〕

概要

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Some aspects of unsteady viscous flow field around an oar blade of a rowing boat are studied numerically by means of laminar, incompressible unsteady full 2D Navier-Stokes simulation. Main objectives are to reveal the flow phenomena in order to understand the mechanism of generation of the propulsive force and to study the influence of different parameters on the flow pattern and efficiency of rowing. The main parameters under consideration are : 1) angular velocity of the blade (speed of rowing), 2) blade geometry and 3) outboard length of the oar. Special attention is payed to the unsteady effects taking place during the blade stroke. An analysis of the accuracy and reliability of the results with respect to the limited Reynolds number and 2D simulation is provided. Analysis of the results for the flow simulation and hydrodynamical forces acting on the blade during its stroke shows, that the flow is very sensitive even to the small changes of main motion or geometry parameters, although, a general flow pattern is valid for all of the studied cases. Performed flow simulation shows that for all studied cases, strong and stable vortical structures, formed near the catch position, attend the blade motion and have strong influence on the further flow evolution. This fact determines the strong unsteady effects on the flow pattern and the exerted hydrodynamical forces.
社団法人日本船舶海洋工学会の論文