THREE - DIMENSIONAL EFFECTS IN VISCOUS WAKES

Abstract

Abstract : TLYTECHNIC Inst. of Brooklyn, N. Y. THREE-DIMENSIONAL EFFECTS IN VISCOUS WAKES, by Martin H. Steiger and Martin H. Bloom. June 62, 32p. incl. illus. table, 9 refs. (PIBAL rept. no. 711) (Contract AF $((638)445, Proj. 9781) Unclassified report DESCRIPTORS: *Wake, *Fluid flow, Compressible flow, Jet mixing flow, Viscosity, Turbulent flow, Laminar boundary layer, Turbulent bound ary layer, Integral equations, Mathematical analysis. Three-dimensionality in wake-like or jet-like free-mixing is investigated. The first section of the report deals with the general mathematical model, in which the boundary layer approximations are used and with methods of solution. Laminar and turbulent flow, compressibility, unsteadiness and streamwise pressure gradients are admitted initially. The flux forms of the equations are given. Algebraic integrals of the energy equations and the diffusion (frozen-flow) equations are obtained. A simplification of the convective terms, roughly corresponding to the Oseen approximation, is used in the asymptotic downstream region. This results in linearization in the case of constant-fluid-properties, and permits the derivation of convenient solutions. Corresponding first-approximation solutions are obtained for the compressible case. Finally, second-approximation improvements are derived. The second section contains explicit solutions for specific configurations, in particular for flows whose initial isovels are of elliptic shape. These flows may be wake-like or jet-like. Compressibility is admitted; however, the flows must have uniform pressure and be steady. The final section deals with interpretation and evaluation of the results. (Author)