Visualization of flow past a square prism with cut-corners at the front-edge

Flow past a square prism with cut-corners at the front-edge is numerically and experimentally visualized to investigate a mechanism of drag reduction. An adaptive numerical scheme based on the vortex method is implemented for two values of the Reynolds number between 200 and 1,250, and the results are compared with experiments. Experimental visualization techniques include the hydrogen-bubble technique atRe=4,000 and the oil-flow technique atRe=10,000 for a global wake formation, and the aluminum-flake technique for transient flow at the early stage of motion atRe=1,250. A similar reattachment flow pattern is shown in a wide range of the Reynolds number between 200 and 10,000, which implies a possibility of the drag reduction in the Reynolds number being approximately lower than 8,000 unlike the previous findings.