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

Inverse Solutions for Laminar Boundary-layer Flows with Separation and Reattachment
Author: James Edward Carter
Publisher:
Total Pages: 72
Release: 1975
Genre: Boundary layer
ISBN:

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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.

A Study of Non-Unique Solutions of the Two-Dimensional Boundary Layer Equations at Laminar Separation and Reattachment Points

A Study of Non-Unique Solutions of the Two-Dimensional Boundary Layer Equations at Laminar Separation and Reattachment Points
Author: M. Drela
Publisher:
Total Pages: 8
Release: 1981
Genre:
ISBN:

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The possibility of non-unique solutions to the laminar boundary equations in direct problem calculations has been identified for decelerating flow. For flows far from separation or reattachment one solution is physically reasonable and the others unrealistic. As a separation or reattachment point is approached, the multiple solutions approach each other and become identical. Understanding of this behavior allows direct problem calculations through separation, although such calculations are not practical. The computer code used to generate these results was developed to solve compressible, laminar or turbulent boundary layer and free wake problems in direct or inverse mode. The equation formulation uses a variable scaling based on the local displacement thickness rather than the more common Levy-Lees scaling or stream function form are possible.

NASA Technical Report

NASA Technical Report
Author: United States. National Aeronautics and Space Administration
Publisher:
Total Pages: 872
Release: 1975
Genre: Aerodynamics
ISBN:

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NASA Technical Paper

NASA Technical Paper
Author:
Publisher:
Total Pages: 60
Release: 1978
Genre: Science
ISBN:

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

An Inverse Boundary-Layer Method for Compressible Laminar and Turbulent Flows
Author: Tuncer Cebeci
Publisher:
Total Pages: 50
Release: 1975
Genre: Boundary layer
ISBN:

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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.