Boundary Layer Separation in the Presence of Heat Transfer

Boundary Layer Separation in the Presence of Heat Transfer
Author: G. E. Gadd
Publisher:
Total Pages: 13
Release: 1960
Genre: Boundary layer
ISBN:

Effects of heat transfer on the separation of laminar boundary layers in supersonic flow are considered theoretically and experimentally. In theory, cooling the wall reduces the extent of regions of separation and steepens the pressure gradients, whilst heating the wall has opposite effects. The experimental results partially confirm these predictions. (Author).

Separation of Flow

Separation of Flow
Author: Paul K. Chang
Publisher: Elsevier
Total Pages: 800
Release: 2014-06-28
Genre: Technology & Engineering
ISBN: 1483181286

Interdisciplinary and Advanced Topics in Science and Engineering, Volume 3: Separation of Flow presents the problem of the separation of fluid flow. This book provides information covering the fields of basic physical processes, analyses, and experiments concerning flow separation. Organized into 12 chapters, this volume begins with an overview of the flow separation on the body surface as discusses in various classical examples. This text then examines the analytical and experimental results of the laminar boundary layer of steady, two-dimensional flows in the subsonic speed range. Other chapters consider the study of flow separation on the two-dimensional body, flow separation on three-dimensional body shape and particularly on bodies of revolution. This book discusses as well the analytical solutions of the unsteady flow separation. The final chapter deals with the purpose of separation flow control to raise efficiency or to enhance the performance of vehicles and fluid machineries involving various engineering applications. This book is a valuable resource for engineers.

Boundary Layer Effects

Boundary Layer Effects
Author: Anthony W. Fiore
Publisher:
Total Pages: 962
Release: 1978
Genre: Turbulent boundary layer
ISBN:

In 1975 the U.S. Air Force and the Federal Republic of Germany signed a Data Exchange Agreement numbered AF-75-G-7440 entitled 'Viscous and Interacting Flow Fields.' The purpose was to exchange data in the area of boundary layer research. It includes both experimental and theoretical boundary layer research at speeds from subsonic to hypersonic Mach numbers in the presence of laminar, transitional, and turbulent boundary layers. The main effort in recent years has been on turbulent boundary layers, both attached and separated in the presence of such parameters as pressure gradients, wall temperature, surface roughness, etc. In the United States the research was conducted in various Department of Defense, NASA, aircraft corporations, and various university laboratories. In the Federal Republic of Germany it was carried out within the various DFVLR, industrial, and university research centers.

Laminar Boundary-layer Separation on Flared Bodies at Supersonic and Hypersonic Speeds

Laminar Boundary-layer Separation on Flared Bodies at Supersonic and Hypersonic Speeds
Author: J. Don Gray
Publisher:
Total Pages: 64
Release: 1965
Genre: Laminar boundary layer
ISBN:

Experiments at supersonic speeds and at Mach 8 were conducted to determine the conditions which govern the extent of shock-induced laminar flow separations on axisymmetric configurations at zero yaw and without heat transfer. From an extensive correlation of surface pressure data and schlieren photographs, it is shown that the extent of reverse flow is essentially a function of the ratio of the wetted length to the flare divided by the laminar boundary thickness there. As a result, the relative extent of laminar flow separation decreases with a unit Reynolds number increase and grows through an increase in Mach number. Finally, increasing the flare angle increases the length of the reverse flow region.

LAMINAR SEPARATION IN SUPERSONIC FLOW.

LAMINAR SEPARATION IN SUPERSONIC FLOW.
Author: Jean J. Ginoux
Publisher:
Total Pages: 75
Release: 1964
Genre:
ISBN:

Detailed experimental investigations were made at a Mach number of 2.21 of laminar flows over ramps, backward facing steps and swept back wings. Large spanwise variations of the heat transfer coefficient (h) were measured, with two different techniques, in the reattachment region of the flow over a backward facing step and were related to streamwise vortices present in the laminar boundary layer. Peaks in h much larger than the turbulent value were measured. By comparing spanwise total head and heat transfer rate distributions, Reynolds analogy was found to apply quantitatively for reattaching flows with streamwise vortices. The effect of free-stream Reynolds number and of leading edge sweep, accuracy of machining, thickness and bevel angle on the intensity of streamwise vortices present in the boundary layer on swept back wings was investigated. Flow separation was detected at the leading edge. A regular pattern of streamwise vortices of small wave length was observed outside of the boundary layer.

Boundary Layer Transition at Supersonic Speeds

Boundary Layer Transition at Supersonic Speeds
Author: E. R. Van Driest
Publisher:
Total Pages: 108
Release: 1961
Genre: Aerodynamics, Supersonic
ISBN:

Experiments carried out in the 12-inch supersonic wind tunnel to investigate the effect of three dimensional roughness elements (spheres) on boundary-layer transition on a 10-degree (apex angle) cone without heat transfer are described. The local Mach number for these tests was 2.71. The data show clearly that the minimum (effective) size of trip required to bring transition to its lowest Reynolds number varies power of the distance from the apex of the cone to the trip. Use of available data at other Mach numbers indicates that the Mach number influence for effective tripping is taken into account by a simple expression. Some remarks concerning the roughness variation for transition on a blunt body are made. Finally, a general criterion is introduced which gives insight to the transition phenomenon and anticipates effects of external and internal disturbances, Mach number transfer.