Experimental investigation on wall pressure distribution in flaps’ separating regions

Abstract

Abstract The effects on the wall pressure of the plate caused by the introduction of a gap near the ground and the flaps were investigated experimentally. The mean pressure on the plate surface was found to decrease with the size changing of the gap near the ground when the gap size (g) is larger than the flap height (h), but the one in the recirculation region increase with the size of the gap when the gap size is about 0 ≤ g ≤ 2h. Three kinds of flow structure appear with increasing the gap sizes, and the transit point is at g/h = 0·2, 0·8 respectively. For the zigzag flap (d/h = 0·19, d is the height of the zigzag), the variation of wall pressure with g/h is similar to the flat flap in general. The zigzag affects the mean wall pressure in the region of 0 ≤ x/h ≤ 20 (the recirculation zone) and can decrease the fluctuating pressure in the region of x/h > 20 downstream.