Turbulent separation flows

Using the perturbation method to solve the problem of separated incompressible flow past thin airfoils

“…Additional difficulties arise in flow averaging because separated airfoil flow is always unsteady and tends to steady-state flow only on the average [2].…”

“…Separated flows past bodies have been the subject of extensive research [1][2][3]. A classification of computational techniques for such flows is given in [2]. A separate group is distinguished that contains vortex models for inviscid flow using additional hypotheses such as the Joukowski-Chaplygin hypothesis, for which the main approaches to numerical implementation are described in [1].…”

“…Separated flows past bodies have been the subject of extensive research [1][2][3]. A classification of computational techniques for such flows is given in [2].…”

Effect of the boundary layer on the base pressure in a two-dimensional flow with a Mach number M = 5

“…This problem is discussed in the present paper, which describes detailed measurements of the base pressure on the edge of a two-dimensional body in a supersonic flow with a Mach number M = 5 in a wide range of variation of the boundary-layer thickness at the exit, up to δ/(t/2) = 3.2. The experimental data obtained are used to test Tanner's numerical model [5][6][7], which, in contrast to other known numerical methods (see, e.g., [1][2][3][4]) claims that it can predict the base drag for bodies of different geometries for arbitrary values of M and δ/(t/2), and which was previously tested at lower Mach numbers.Setup, Models, and Measurement Technique. The base pressure was measured at the edge of a nozzle blade in the course of extensive studies of the flow structure formed by a block of two-dimensional supersonic nozzles [8] (as applied to the problem of optical quality of the active medium of the gas-dynamic laser [9, 10]).…”

“…The problem of the near wake and, in particular, the base drag is discussed in numerous experimental and theoretical studies. A large list of papers on this topic can be found in the review [1] and monographs [2][3][4]. Various experiments and simplified numerical models are used to study the dependence of the base pressure of bodies with different configurations on the basic governing parameters, which is usually presented in the form p b /p e = f (M e , α, δ/(t/2) or δ * * /(t/2)), where M e is the free-stream Mach number, δ is the boundary-layer thickness, δ * * is the momentum thickness, t/2 is the half-height (radius) of the base cross section, and α is the angle of deviation of the body contour from the free-stream direction in the flow-separation cross section.…”