title: Random roughness enhances lift in supersonic flow.
abstract: We study the scattering of shock waves by a rough wedge using second-order perturbation analysis and stochastic simulations employed synergistically to cover a large range in correlation length A and amplitude epsilon of the profile roughness (with length d). For small epsilon and A/d<<1, the mean of the perturbed pressure scales alpha epsilon2 and alpha (A/d)(-2), while the corresponding variance scales alpha epsilon and alpha (A/d)(-1). However, for large epsilon, the mean pressure scales approximately alpha epsilon, while for A/d>1 it is independent of A. Our results are useful in evaluating the effects of roughness in high-speed flight but also in designing novel enhanced-lift aerodynamic surfaces using rough skin concepts.
authors.affiliation: Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA. glin@dam.brown.edu
authors.forename: Guang
authors.initials: G
authors.lastname: Lin
authors.forename: Chau-Hsing
authors.initials: CH
authors.lastname: Su
authors.forename: George Em
authors.initials: GE
authors.lastname: Karniadakis