Effect of High Mach Numbers on High-Speed Aircraft

2010 ◽  
pp. 375-442
Keyword(s):  
High Speed ◽  
Mach Numbers ◽  
High Mach

Study of Airscrews for High Speed Aeroplanes

1940 ◽  
Vol 44 (352) ◽  
pp. 322-337
Author(s):  
Lucio Lazzarino
Keyword(s):  
Special Reference ◽  
Present Article ◽  
High Speed ◽  
Numerical Evaluation ◽  
Experimental Results ◽  
Aerodynamic Efficiency ◽  
Angular Velocities ◽  
Mach Numbers ◽  
High Mach

RésuméIt is demonstrated how, with increase in speed, the diameter of optimum efficiency and the maximum possible value of efficiency of an airscrew diminish. The efficiency of a system of two counter-revolving airscrews with different angular velocities is then determined, and the variation of efficiency with variation in the relation between the angular velocities of the two airscrews.With increase in the height and speed of flight, airscrew performance inevitably falls off, frequently in a marked degree; this being mainly due to the decrease in aerodynamic efficiency of the blade sections at high Mach numbers.The object of the present article is to analyse the influence exerted upon the performance of an airscrew by the various parameters that determine it, wit-h special reference to those connected with the speed and height of flight.A similar study has also been made of systems constituted of two counter-rotating airscrews, with a view to comparing them with isolated airscrews designed to absorb the same power under identical conditions.By the methods here described, an approximate numerical evaluation of the performance can be made, utilising the experimental results which are already to hand.

scholarly journals Revaluation of Researches on the Free Rotating Vaneless Diffusor

1989 ◽  
Author(s):  
Yves Ribaud ◽  
Christian Fradin
Keyword(s):  
High Speed ◽  
Mechanical Design ◽  
Free Rotation ◽  
Vaneless Diffuser ◽  
Low Speed ◽  
Mach Numbers ◽  
High Mach

After eighteen years, an attempt is now being made to revaluate the studies performed by RODGERS-MNEW and RIBAUD-FRADIN on the rotating vaneless diffuser. These two studies are complementary. The first deals with a high speed rotating vaneless diffusor fed by a swirl generating nozzle and giving high Mach numbers. The second concerns a real compressor comprising a low speed rotor followed by a rotating vaneless diffuser. The free rotation of the vaneless diffusor reduces the friction losses by about 70%. The high speed, mechanical design of the rotating vaneless diffusor is a success. The structure of the flow at the rotor outlet seems to have an important effect on the efficiency of the rotating vaneless diffusor. New types of rotating vaneless diffusors should be experimented and new comparative experiments attempted. The application of the rotating vaneless diffusor concept to low specific speeds compressors is also proposed.

Magnetic–Internal–Kinetic Energy Interactions in High-Speed Turbulent Magnetohydrodynamic Jets

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Divya Sri Praturi ◽  
Sharath S. Girimaji
Keyword(s):  
Velocity Field ◽  
Kinetic Energy ◽  
High Speed ◽  
Magnetic Pressure ◽  
Velocity Perturbation ◽  
Perturbation Mode ◽  
Magnetic Tension ◽  
Consequent Effect ◽  
Mach Numbers ◽  
High Mach

Abstract The goal of this study is to investigate the interactions between turbulent kinetic, internal, and magnetic energies in planar magnetohydrodynamic (MHD) jets at different regimes of Mach and Alfvén Mach numbers. Toward this end, temporal simulations of planar MHD jets are performed, using two types of initial fluctuating velocity field: (i) single velocity perturbation mode with a streamwise wavevector and (ii) random, isotropic perturbations over a band of wavevectors. At low Mach numbers, magnetic tension work results in a reversible exchange of energy between fluctuating velocity and magnetic fields. At high Alfvén Mach numbers, this exchange results in the equipartition of turbulent kinetic and magnetic energies. At higher Mach numbers, dilatational kinetic energy is (reversibly) exchanged with internal and magnetic energies, by means of pressure-dilatation and magnetic-pressure-dilatation, respectively. Therefore, at high Mach and Alfvén Mach numbers, dilatational kinetic energy is seen to be in equipartition with the sum of turbulent internal and magnetic energies. In each of the regimes, the consequent effect of the interactions on the background Kelvin–Helmholtz vortex evolution is also identified.

High Speed Photography For Studying The Shock Wave Propagation At High Mach Numbers Through A Reflection Nozzle

1979 ◽  
Author(s):  
S. G. Zaytsev ◽  
E. V. Lazareva ◽  
A. V. Mikhailova ◽  
V. L. Nikolaev-Kozlov ◽  
E. I. Chebotareva
Keyword(s):  
Shock Wave ◽  
Wave Propagation ◽  
High Speed ◽  
Shock Wave Propagation ◽  
High Speed Photography ◽  
Mach Numbers ◽  
High Mach

MULTIDIMENSIONAL SIMULATIONS AND TEST FIRES OF A HYDROGEN-FUELED RAMJET WITH AN ANNULAR DETONATIVE COMBUSTOR AT APPROACHING AIR FLOW OF MACH 2 AND 1.5

2020 ◽  
Author(s):  
V. S. IVANOV ◽  
◽  
V. S. AKSENOV ◽  
S. M. FROLOV ◽  
P. A. GUSEV ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicles ◽  
High Speed ◽  
Constant Pressure ◽  
Air Flow ◽  
Thermodynamic Cycle ◽  
Aerial Vehicles ◽  
Mach Numbers

Modern high-speed unmanned aerial vehicles are powered with small-size turbojets or ramjets. Existing ramjets operating on the thermodynamic cycle with de§agrative combustion of fuel at constant pressure are efficient at flight Mach numbers M ranging from about 2 to 6.

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.

An Improved Hybrid Alternative WENO Scheme for High Mach Number Flows

2021 ◽  
Author(s):  
Uttam Singh Rajput ◽  
Krishna Mohan Singh
Keyword(s):  
High Speed ◽  
Compressible Flows ◽  
Weno Scheme ◽  
Test Cases ◽  
Present Scheme ◽  
Low Dissipation ◽  
Scale Structures ◽  
High Mach ◽  
Fifth Order ◽  
High Resolution Method

Abstract This study presents the development of a fifth-order hybrid alternative mapped weighted essentially non-oscillatory scheme (HAW-M) for high-speed compressible flows. A new, improved smoothness indicator has been developed to design the HAW-M scheme. The performance of the present scheme has been evaluated through different one and two-dimensional test cases. The developed scheme shows higher accuracy and low dissipation. Further, it captures the fine-scale structures smoothly than the existing high-resolution method.

Aeroelastic Problems in connection with High-Speed Flight

1956 ◽  
Vol 60 (547) ◽  
pp. 459-475 ◽  
Author(s):  
E. G. Broadbent
Keyword(s):  
Mach Number ◽  
High Speed ◽  
The Other ◽  
Control Surface ◽  
The Past ◽  
Other Hand ◽  
Aerodynamic Derivatives ◽  
Mach Numbers ◽  
The One

SummaryA review is given of developments in the field of aeroelasticity during the past ten years. The effect of steadily increasing Mach number has been two-fold: on the one hand the aerodynamic derivatives have changed, and in some cases brought new problems, and on the other hand the design for higher Mach numbers has led to thinner aerofoils and more slender fuselages for which the required stiffness is more difficult to provide. Both these aspects are discussed, and various methods of attack on the problems are considered. The relative merits of stiffness, damping and massbalance for the prevention of control surface flutter are discussed. A brief mention is made of the recent problems of damage from jet efflux and of the possible aeroelastic effects of kinetic heating.

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