An Experimental Study of Flow Over a Rectangular Body

Abstract

An experimental investigation has been performed to determine the surface pressure distribution on models of rectangular cross section in a two dimensional incompressible flow as a function of angle of attack and freestream velocity. Data were obtained at angles of attack from 0 deg where a separation bubble exists on both upper and lower surfaces, to 40 deg where the flow resembles that about a flat plate. Existing theoretical analyses appear adequate for predicting the nature of the flow given the angle of attack and aspect ratio and for predicting the pressure distribution if the flow is similar to that around an inclined flat plate. At the low angles of attack the pressure inside the separation bubble appears to follow a “universal” nondimensional plot and the flow after reattachment is turbulent. At higher angles a stagnation line exists on the upper surface and the flow is laminar. Extreme favorable pressure gradients at these angles lie in a range which has been found previously to inhibit the generation of turbulence.