Correlation of artificially induced boundary-layer transition data at hypersonic speeds

Abstract

Previous investigations of distributed-roughness boundary-layer trips indicated that they are superior to spherical-type trips in that equally effective distributed-roughness trips are one-fifth as high and produce substantially smaller flowfield disturbances. The present work has expanded the data base, permitting correlation of distributed-roughness tripping data. The correlation thus developed includes a wide range of Reynolds numbers, cone angles, and trip heights. Plots are provided that permit the selection of distributed-roughness trips without the need of boundary-layer solutions. Nomenclaturek = trip element height, in. M^ = freestream Mach number P E = pressure at the end of the roughness area (s/r,, =5), psia P' 0 = freestream pitot pressure, psia p^ = freestream pressure, psia q^ = freestream dynamic pressure, psia Re eQ = Reynolds number based on boundary-layer edge conditions and momentum thickness Re er -Reynolds number based on boundary-layer edge conditions and model nose radius Re^/ft = Reynolds number based on freestream conditions and a 1 ft length Re^> r = Reynolds number based on freestream conditions and model nose radius r b = model base radius, in. r n = model nose radius, in. s = surface distance along the model measured from the stagnation point, in. T e = temperature at the edge of the boundary layer,°R T 0oo = freestream total temperature, °R T™ = model wall temperature, °R r^ = freestream temperature, °R X = Mayne's correlation parameter, see Eq. (3) 6 = boundary-layer momentum thickness, in. O c = model cone half-angle, deg X = PANT correlation parameter, see Eq. (1) X^ = modified PANT correlation parameter evaluated at the sonic point, see Eq. (5) Subscripts critical = value of the parameter needed to bring transition t up to or near the trip = at the end of transition Superscript = evaluated at the sonic point

Effects of Roughness on Hypersonic Boundary-Layer Transition

“…Boudreau [81] developed a method for tripping the boundary layer on the frustum of hypersonic sphere cones using relatively small roughness distributed over the nose tip. The correlation is supported with seven datasets at Mach 6-13 in tunnels B and F at AEDC, and also with PANT data.…”

Hypersonic Laminar-Turbulent Transition Experiment Design: From Wind Tunnel Model Definition to MDOE Approach

“…For Re ≥ r , this type of transition, as predicted in the original PANT criterion, should be considered possible. Some authors [28] examined the effect of nose radius in case of sphere-cone models and proposed a criterion taking explicitly into account the nose Reynolds number.…”