Author: Frank Levi YoungPublisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 310
Book Description
Experimental investigation of the effects of surface roughness on compressible turbulent boundary layer skin friction and heat transfer
Author: Frank Levi YoungPublisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 310
Book Description
Compressible Turbulent Skin Friction on Rough and Rough/wavy Walls in Adiabatic Flow
Author: Daniel C. RedaPublisher:
ISBN:
Category : Fluid mechanics
Languages : en
Pages : 80
Book Description
An experimental program was conducted to investigate effects of roughness, and roughness superimposed on single and/or multiple, shallow, periodic waveforms, on turbulent boundary-layer skin friction and velocity profile, in compressible, adiabatic flow. Test conditions were Mach number = 2.9 and Reynolds number/ft = 2 million to 8 million. The planar models included smooth, sand-grain, machined and molded surface finishes. Direct measurements of surface shear and Pitot/recovery temperature profiles were obtained. (Modified author abstract).
An Experimental Investigation of the Effects of Several Types of Surface Roughness on Turbulent Boundary Layer Characteristics at Supersonic Speeds
Author: Felix W. FenterPublisher:
ISBN:
Category :
Languages : en
Pages : 63
Book Description
A theory is described which can be used to predict accurately the skin friction drag of surfaces with uniform grain-type roughness. The roughness does not necessarily have to extend to the leading edge of the surface for an accurate calculation to be made. Uniform surface roughness composed of spherical beads does not affect the boundary layer in a manner significantly different from grain-type roughness, provided that the grains and the spheres are bonded to the surface in a similar manner. Consequently, the theory accurately predicts the effects of spherical roughness elements on skin friction under these conditions. The effect of a given type of roughness on turbulent boundary layer characteristics is strongly dependent upon the density of distribution of the roughness elements. The effect of maximum density V-grooves on turbulent boundary layer characteristics is dependent upon the sweepback angle. The effect of increasing sweepback is to reduce the skin friction drag. (Author).
NASA Technical Note
Author: Analytical, Numerical, and Experimental Results on Turbulent Boundary Layers
Author: David L. WhitfieldPublisher:
ISBN:
Category : Laminar boundary layer
Languages : en
Pages : 108
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).
Research Review
Author: Research Review
Author: United States. Air Force. Office of Aerospace ResearchPublisher:
ISBN:
Category : Astronautics
Languages : en
Pages : 138
Book Description
An Analytical Investigation of the Flat Plate Turbulent Boundary Layer in Compressible Flow
Author: Neal TetervinPublisher:
ISBN:
Category : Skin friction (Aerodynamics)
Languages : en
Pages : 168
Book Description
The concepts of eddy kinematic viscosity and eddy diffusivity are used to calculate skin friction and heat transfer coefficients for the turbulent boundary layer on a flat plate. The eddy kinematic viscosity, eddy diffusivity, and turbulent Prandtl number vary across the boundary layer. The Mach number range is from zero to ten. The surface to stream temperature ratio varies from one-half to eight, and includes the insulated surface. The friction results are compared with experimental data. Velocity and temperature profiles for the entire region from the surface to the outer edge are compared with experimental data. (Author).
Technical Abstract Bulletin
Author: Skin Friction and Heat Transfer in Turbulent Boundary Layers as Influenced by Roughness
Author: Milton J. ThompsonPublisher:
ISBN:
Category :
Languages : en
Pages : 96
Book Description
The report provides a summary of theoretical and experimental research on turbulent boundary layers under supersonic free stream conditions. The program included investigations of boundary layer behavior at various Mach Numbers for smooth, adiabatic surfaces, various types of surface roughness, and the combined effects of roughness and heat transfer. The experimental program involved velocity profile measurements and the momentum deficit method of calculating skin friction, determinations of local shear stress values, and the utilization of plug-type calorimeters for determinations of heat transfer rates.