An Inverse Boundary-Layer Method for Compressible Laminar and Turbulent Flows


Book Description

This report presents an efficient method for calculating laminar and turbulent boundary-layer flows for standard and inverse boundary-value problems. It is applicable to both incompressible and compressible flows. The standard boundary-layer problem considers the solution of the usual boundary-layer equations for a given external velocity distribution. The inverse problem considers the solution of the governing equations for assigned wall shear or assigned displacement thickness.




Analysis of Turbulent Boundary Layers


Book Description

Analysis of Turbulent Boundary Layers focuses on turbulent flows meeting the requirements for the boundary-layer or thin-shear-layer approximations. Its approach is devising relatively fundamental, and often subtle, empirical engineering correlations, which are then introduced into various forms of describing equations for final solution. After introducing the topic on turbulence, the book examines the conservation equations for compressible turbulent flows, boundary-layer equations, and general behavior of turbulent boundary layers. The latter chapters describe the CS method for calculating two-dimensional and axisymmetric laminar and turbulent boundary layers. This book will be useful to readers who have advanced knowledge in fluid mechanics, especially to engineers who study the important problems of design.




Boundary Layer Flows


Book Description

This book provides a comprehensive overview of boundary layer flows, including laminar and turbulent flows. Chapters discuss such topics as the nature of transition, the effect of two-dimensional and isolated roughness on laminar flow, and progress in the design of low-drag airfoils. They also present theoretical and experimental results in boundary layer flows and discuss directions for future research.







Inverse Solutions for Laminar Boundary-layer Flows with Separation and Reattachment


Book Description

Numerical solutions of the laminar, incompressible boundary-layer equations are presented for flows involving separation and reattachment. Regular solutions are obtained with an inverse approach in which either the displacement thickness or the skin friction is specified; the pressure is deduced from the solution. A vorticity--stream-function formulation of the boundary-layer equations is used to eliminate the unknown pressure. Solutions of the resulting finite-difference equations, in which the flow direction is taken into account, are obtained by several global iteration schemes which are stable and have unconditional diagonal dominance. Results are compared with Klineberg and Steger's separated boundary-layer calculations, and with Briley's solution of the Navier-Stokes equations for a separated region. In addition, an approximate technique is presented in which the streamwise convection of vorticity is set equal to zero in the reversed flow region; such a technique results in a quick forward-marching procedure for separated flows.













The Turbulent Boundary Layer in a Compressible Fluid


Book Description

The first object of the paper is to develop a transformation which reduces the boundary-layer equations for compressible two-dimensional mean turbulent motion to incompressible form. The second object is to apply this transformation to the special case of the adiabatic turbulent boundary layer on a smooth wall. The transformation represents at every stage a genuine kinematic and dynamic correspondence between two real flows, both of which are capable of being observed experimentally. Since the mean pressure and mean velocity can then be measured in either flow, the mean acceleration of the fluid can in principle be determined, and the shearing stress can be adequately and accurately defined as the stress which is necessary to account for this acceleration. This formulation leads to a general transformation valid for laminar or turbulent flow in wakes and boundary layers, without regard to the state or energy equations or the viscosity law for the compressible fluid, and without regard to the boundary conditions on surface pressure or temperature in the event that a surface is involved. (Author).