Steady State Characteristics of Scramjet Engines Using Hydrogen for High Mach Numbers

2017 ◽  
Author(s):  
Zifei Ji ◽  
Bing Wang ◽  
Huiqiang Zhang
Keyword(s):  
Steady State ◽  
Mach Numbers ◽  
Scramjet Engines ◽  
High Mach

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.

The Helicopter Rotor at High Mach Numbers

1968 ◽  
Vol 13 (2) ◽  
pp. 56-64
Author(s):  
W. H. Tanner ◽  
J. F. VanWyckhouse ◽  
Patrick Cancro ◽  
John McCloud
Keyword(s):  
Helicopter Rotor ◽  
Mach Numbers ◽  
High Mach

Relation Between Sound Sources and Vortical Structures in Isotropic Compressible Turbulence

2014 ◽  
Author(s):  
Daiki Terakado ◽  
Taku Nonomura ◽  
Makoto Sato ◽  
Kozo Fujii
Keyword(s):  
Mach Number ◽  
Sound Source ◽  
Compressible Turbulence ◽  
Fine Scale ◽  
Sound Sources ◽  
Vortical Structures ◽  
Scale Structures ◽  
Mach Numbers ◽  
High Mach ◽  
Lighthill Equation

We investigate the relation between vortical structures and sound source in isotropic compressible turbulence by direct numerical simulations with various turbulent Mach numbers. The sound source is obtained numerically from the Lighthill equation. As a first step, we study the sound source from the Reynolds stress, which is the dominant source in flows at low Mach numbers. We investigate, especially, sound source structures around the “coherent fine scale eddies” [1–4] to lead a universal conclusion of sound generation mechanism from the fine scale structures in supersonic flows. We find that the sound source structures around the coherent fine scale eddies show some distorted structures only in high Mach number flows because shocklets appear around the fine scale eddies in those flows. This change in sound source structures around the coherent fine scale eddies does not appear in low and moderate Mach number cases.

Compressibility effects in a turbulent annular mixing layer. Part 1. Turbulence and growth rate

2000 ◽  
Vol 421 ◽  
pp. 229-267 ◽  
Author(s):  
JONATHAN B. FREUND ◽  
SANJIVA K. LELE ◽  
PARVIZ MOIN
Keyword(s):  
Growth Rate ◽  
Mach Number ◽  
Mixing Layer ◽  
Mixing Layers ◽  
Velocity Difference ◽  
Mean Velocity ◽  
The Mean ◽  
Mach Numbers ◽  
High Mach ◽  
Compressibility Effects

This work uses direct numerical simulations of time evolving annular mixing layers, which correspond to the early development of round jets, to study compressibility effects on turbulence in free shear flows. Nine cases were considered with convective Mach numbers ranging from Mc = 0.1 to 1.8 and turbulence Mach numbers reaching as high as Mt = 0.8.Growth rates of the simulated mixing layers are suppressed with increasing Mach number as observed experimentally. Also in accord with experiments, the mean velocity difference across the layer is found to be inadequate for scaling most turbulence statistics. An alternative scaling based on the mean velocity difference across a typical large eddy, whose dimension is determined by two-point spatial correlations, is proposed and validated. Analysis of the budget of the streamwise component of Reynolds stress shows how the new scaling is linked to the observed growth rate suppression. Dilatational contributions to the budget of turbulent kinetic energy are found to increase rapidly with Mach number, but remain small even at Mc = 1.8 despite the fact that shocklets are found at high Mach numbers. Flow visualizations show that at low Mach numbers the mixing region is dominated by large azimuthally correlated rollers whereas at high Mach numbers the flow is dominated by small streamwise oriented structures. An acoustic timescale limitation for supersonically deforming eddies is found to be consistent with the observations and scalings and is offered as a possible explanation for the decrease in transverse lengthscale.

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
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