Transition due to Surface Steps in the Presence of Favorable Pressure Gradients

Abstract

The infl uence of favorable pressure gradients on the allowable size of surface steps for laminar flow wings can have a beneficial effect on manufacturing tolerances. However, generally -applicable guidelines for including the effects of pressure gradient on the al lowable size of surface steps do not exist. A series of experiments has been undertaken, in a low speed wind tunnel and a novel propelled -model facility, to obtain data to determine manufacturing tolerances for laminar flow aircraft. Building on that wor k, new models have been designed to conduct testing that will extend the ranges of applicable Reynolds number and pressure gradient to include many future aircraft concepts.