Numerical Simulations of Fluctuating Vortex around a Hydrofoil in Steady Inflow

In order to reduce the drag of the hydraulic elements, we attempt numerical simulations of a typical hydrofoil using the QUICK method, because the computational fluid dynamics are very useful in precisely simulating the details of the local flow characteristics concerning the vorticity and the flow separation around a hydrofoil. In our previous paper, our computational results agree well with the experiments for the power spectra of the lift-and-drag fluctuation of the hydrofoils, as well as the time-averaged values of the lift and the drag. The flow characteristics, therefore, are investigated around the hydrofoil in steady inflow, in particular the characteristic of fluctuating vortex shedding, which concerns the leading-edge-and trailing-edge-shape of the hydrofoil, since these shapes are associated with the separation and are very important factors of the drag and lift. The behavior of the relation between the fluctuating vortex in the separation bubble and the vortex shedding from trailing edge is clarified.