부산대학교 도서관

Ground effect is the effect of the ground on the flow around objects such as trains and cars, moving closely along the ground surface. Here we use a moving belt system that moves at the same speed as the uniform flow to simulate objects moving through the stationary air above the ground in a wind-tunnel. In the present study, we focus on a fundamental object, a flat plate, above the moving belt. We measure the wake of the plate of chord length c and span b using a hot-wire anemometer for the cases with various aspect ratio AR = b/c of the plate and the gap between the plate and the ground h. Next, we perform FFT analysis of the velocity time series to obtain the Strouhal number St. Furthermore, we also perform visualization of the flow around the plate. It is observed that, when the plate approaches to the ground, St slightly increases from its free stream value and shows a sharp peak at a certain value of h/c, which depends on AR.