y 6 6 * e 6 Nomenclature amplitude of Tollmien-Schlichting waves or Gortler vortices; also Van Driest's dampinglength constant amplitude at neutral stability constant in velocity distributions of the form ue = cx profile drag coefficient transformed value of du/dy at the wall in the Falkner-Skan equation height of a roughness exponent in velocities of the form ue = cx measure of amplification ratio, n-^i(A/A0) Prandtl number longitudinal radius of curvature for Gortler vortices chord Reynolds number Reynolds number based on momentum thickness velocity in x direction edge velocity coordinates, generally along and perpendicular to the wall Hartree's boundary-layer profile parameter, note