Wall Temperature Effects on Two- and Three-dimensional Transonic Turbulent Boundary Layers


Book Description

Wall temperature effects on two- and three-dimensional high Reynolds number turbulent boundary layers are examined for representative high Reynolds number tunnel (HIRT) conditions relative to flight; also considered are hot-wall conditions relative to space shuttle subsonic and transonic flight during earth entry. Results show significant influences of wall-to-stagnation temperature ratio on the location of boundary-layer separation and the friction drag coefficient. The study also indicates how rapid model wall temperature during a typical testing period of 2 to 10 sec may be undesirable for HIRT testing since unsteady aerodynamic phenomena can be influenced by rapidly changing turbulent boundary-layer wall temperature levels. (Modified author abstract).




Analytical, Numerical, and Experimental Results on Turbulent Boundary Layers


Book Description

This report describes the results of analytical, numerical, and experimental investigations of incompressible and compressible boundary layers. The subjects considered are (1) Laminar and/or turbulent numerical boundary-layer calculations in which the Reynolds stress is related to the turbulent kinetic energy; (2) an analytical investigation of turbulence near a wall which is not founded on classical mixing-length theory; (3) analytical solutions for relating velocity and temperature throughout turbulent boundary layers for nonunity Prandtl numbers; (4) a description of the data reduction of pitot pressure measurements utilizing these analytical results, and (5) the application of the numerical and analytical results to the analysis of turbulent boundary-layer measurements made in the Propulsion Wind Tunnel Facility (PWT).




Evaluation of a Method for Computation of Separated, Turbulent, Compressible Boundary Layers


Book Description

A computer code for a turbulent, compressible boundary-layer method, capable of carrying out computations in a region of separated flow, is developed and tested. The procedure after separation is to specify either friction velocity or boundary-layer thickness as an independent variable and obtain external velocity as a dependent variable. This requires a trial and error alternation of the specified variable in order to match the desired experimental or computed external velocity. Satisfactorily results were obtained by this method in the analysis of certain specialized cases of separated flow. (Author).







Three-Dimensional Attached Viscous Flow


Book Description

Viscous flow is treated usually in the frame of boundary-layer theory and as two-dimensional flow. Books on boundary layers give at most the describing equations for three-dimensional boundary layers, and solutions often only for some special cases. This book provides basic principles and theoretical foundations regarding three-dimensional attached viscous flow. Emphasis is put on general three-dimensional attached viscous flows and not on three-dimensional boundary layers. This wider scope is necessary in view of the theoretical and practical problems to be mastered in practice. The topics are weak, strong, and global interaction, the locality principle, properties of three-dimensional viscous flow, thermal surface effects, characteristic properties, wall compatibility conditions, connections between inviscid and viscous flow, flow topology, quasi-one- and two-dimensional flows, laminar-turbulent transition and turbulence. Though the primary flight speed range is that of civil air transport vehicles, flows past other flying vehicles up to hypersonic speeds are also considered. Emphasis is put on general three-dimensional attached viscous flows and not on three-dimensional boundary layers, as this wider scope is necessary in view of the theoretical and practical problems that have to be overcome in practice. The specific topics covered include weak, strong, and global interaction; the locality principle; properties of three-dimensional viscous flows; thermal surface effects; characteristic properties; wall compatibility conditions; connections between inviscid and viscous flows; flow topology; quasi-one- and two-dimensional flows; laminar-turbulent transition; and turbulence. Detailed discussions of examples illustrate these topics and the relevant phenomena encountered in three-dimensional viscous flows. The full governing equations, reference-temperature relations for qualitative considerations and estimations of flow properties, and coordinates for fuselages and wings are also provided. Sample problems with solutions allow readers to test their understanding.







AIAA Bulletin


Book Description