EFFECTS OF ROUGHNESS SIZE ON THE POSITION OF BOUNDARY-LAYER TRANSITION AND ON THE AERODYNAMIC CHARACTERISTICS OF A 55° SWEPT DELTA WING AT SUPERSONIC SPEEDS

摘要

An experimental investigation has been conducted to determine the effects of roughness size on the position of boundary-layer transition and on the aerodynamic characteristics of a 55° swept-delta-wing model. Results are presented and discussed for wind-tunnel tests conducted at free-stream Mach numbers from 1.50 to 4.63, Reynolds numbers per meter from 3.3 x 106 to 1.6 x 107, angles of attack from -8° to 16°, and roughness sizes ranging from 0.027-cm sand grit to 0.127-cm-high cylinders. Comparisons are made with existing flat-plate data. An approximate method is derived for predicting the drag of roughness elements used in boundary-layer trips.