Unsteady boundary-layer induced pressures at high Mach numbers

1982 ◽  
Vol 42 (1-2) ◽  
pp. 37-48
Author(s):  
R. N. Gupta ◽  
S. Mukherjee ◽  
C. M. Rodkiewicz
Keyword(s):  
Boundary Layer ◽  
Unsteady Boundary Layer ◽  
Mach Numbers ◽  
High Mach

scholarly journals Non-localized boundary layer instabilities resulting from leading edge receptivity at moderate supersonic Mach numbers

2018 ◽  
Vol 838 ◽  
pp. 435-477 ◽  
Author(s):  
M. E. Goldstein ◽  
Pierre Ricco
Keyword(s):  
Boundary Layer ◽  
Asymptotic Expansions ◽  
Critical Angle ◽  
Free Stream ◽  
Leading Edge ◽  
Unsteady Boundary Layer ◽  
Instability Waves ◽  
Acoustic Disturbances ◽  
Mach Numbers ◽  
Layer Flow

This paper uses matched asymptotic expansions to study the non-localized (which we refer to as global) boundary layer instabilities generated by free-stream acoustic and vortical disturbances at moderate supersonic Mach numbers. The vortical disturbances produce an unsteady boundary layer flow that develops into oblique instability waves with a viscous triple-deck structure in the downstream region. The acoustic disturbances (which for reasons given herein are assumed to have obliqueness angles that are close to a certain critical angle) generate slow boundary layer disturbances which eventually develop into oblique stable disturbances with an inviscid triple-deck structure in a region that lies downstream of the viscous triple-deck region. The paper shows that both the vortically generated instabilities and the acoustically generated oblique disturbances ultimately develop into modified Rayleigh-type instabilities (which can either grow or decay) further downstream.

The aerodynamic resistance to a sphere rotating at high Mach numbers in the rarefied transition régime

1966 ◽  
Vol 293 (1433) ◽  
pp. 156-168 ◽  
Keyword(s):  
Experimental Study ◽  
Aerodynamic Resistance ◽  
Pressure Gauge ◽  
Transition Regime ◽  
Drag Torque ◽  
Free Molecule ◽  
Rotating Sphere ◽  
Mach Numbers ◽  
High Mach ◽  
Molecule Flow

An experimental study has been made of the gaseous drag torque on an isolated sphere rotating at high Mach numbers. The sphere was suspended electromagnetically and spun by induction. The drag torque has been measured through the transition régime from continuum to free molecule flow at Mach numbers (based on equatorial speed) of up to about five. These high Mach numbers were achieved in heavy vapours (diiodomethane, germanium tetrabromide and stannic bromide) with sonic speed as little as a quarter of that in air. To measure the pressure in the vapour a second (smaller) rotating sphere was used as a pressure gauge. The results agree well with those previously obtained and show an unexpected Mach number dependence in the transition régime.

Some Practical Aspects of Kinetic Heating Calculations

1959 ◽  
Vol 63 (587) ◽  
pp. 637-645 ◽  
Author(s):  
C. L. Bore
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Compressible Flow ◽  
Temperature Variations ◽  
Transfer Rates ◽  
Mach Numbers

This paper is concerned primarily with some of the practical difficulties encountered in connection with the prediction of kinetic heating temperatures. Attention will be concentrated upon methods for estimating temperatures and heat transfer rates for practical aircraft designed to fly at Mach numbers up to about five.One factor common to all kinetic heating calculations is the variation of temperature through the thickness of the boundary layer, with consequent variation of viscosity. At Mach numbers above about 3, these temperature variations also lead to considerable variations of other properties of air—which are commonly assumed to remain constant—even in classical compressible flow aerodynamics. These factors complicate the aerodynamic equations.

Sign in / Sign up

Export Citation Format

Share Document