Dominance of “Noise” on Boundary Layer Transition in Conventional Wind Tunnels — a Place for the “Quiet” Ballistic Range in Future Studies

Abstract

It is the purpose of this paper to briefly review selected boundary layer transition experimental studies and some of the major contributions from 1905 to 1988 that have led to significant advances in boundary layer transition predictions. With this knowledge at hand, comments will be offered as to the type test facilities that could be used to make further significant advances in the future. Progress made in the understanding of laminar and turbulent boundary layer flows and boundary layer transitional flows is illustrated in Figure 1. The development process to date has covered approximately ninety years, beginning in 1905 with the definition of the boundary layer by Prandtl. For the purposes of discussion and evaluation, the development process has been divided into four major phases. As noted in Figure 1, the first three phases have lasted approximately thirty years each. To date, three phases have been completed. We are beginning the fourth phase. Whether or not a fifth phase will be necessary for boundary layer transition and boundary flow theory to become a mature science remains to be seen. The definition of a mature science in this paper is defined as the ability of the theoretical models to adequately predict the location of boundary layer transition relative to the design of ground test experiments and full-scale flight vehicles.