The expansion waves are Mach waves that make a Mach angle with respect to the local flow. The flow through expansion waves is inherently isentropic, as the Mach waves are of infinitesimal strength and hence reversible. An expansion Mach wave is capable of only turning the flow incrementally and accelerates the flow incrementally.
An expansion wave causes a supersonic flow to turn and the static pressure to drop. The expansion waves are Mach waves that make a Mach angle with respect to the local flow. The flow through expansion waves is inherently isentropic, as the Mach waves are of infinitesimal strength and hence reversible.
The Mach numbers are the same, since they depend only upon fL/D (which is the same) and the two nozzle area ratios. If we didn’t know the solution to Prob. 9.91, we would guess Ma
The oblique shocks are compression waves in a supersonic flow that abruptly turn the flow and compress the gas in the process. An expansion wave causes a supersonic flow to turn and the static pressure to drop. The expansion waves are Mach waves that make a Mach angle with respect to the local flow.
The Mach number depends on the speed of sound in the gas and the speed of sound depends on the type of gas and the temperature of the gas. The speed of sound varies from planet to planet.
As the Mach number increases, so does the strength of the shock wave and the Mach cone becomes increasingly narrow. As the fluid flow crosses the shock wave, its speed is reduced and temperature, pressure, and density increase. The stronger the shock, the greater the changes.
Answer C is correct. When passing through an expansion wave the flow's Mach number increases, and the static pressure and density decrease.
The angle formed by the oblique shock with the flow direction is dependent on the Mach number and the angle of deflection of the cone. With increasing Mach number, the conical shock wave becomes acute.
So, in short - the hotter the air, the higher the Mach number, and the faster you must travel over the ground to break the sound barrier. Also - sudden changes of temperature can change the way a jet engine works, but usually that kind of problem is only caused by other jet engines.
In supersonic flow, expansion waves occur when bodies begin to narrow, making more space available. In passing through an expansion wave, air velocity increases, while temperature and pressures are reduced.
As mentioned above, the Mach number of a supersonic flow increases through an expansion fan.
Behind an oblique shockwave the mach number will reduce but the flow will remain supersonic (i.e. greater than Mach 1). When air has passed through a shock wave the speed of sound is increased (due to temperature rise). Thus Mach number reduces.
Expansion waves occur whenever a supersonic flow turns in such a way as to expand in the direction of the flow (i.e., the flow streamlines expand). The expansion region is continuous in that the properties vary relatively smoothly and continuously, which is opposite to the abrupt change across a shock.
Shock-Expansion Theory. The combination of oblique-shock relations and Prandtl-Meyer wave relations constitutes Shock-Expansion Theory, which can be used to determine the flow properties and forces for simple 2-D shapes in supersonic flow. Flat-plate supersonic airfoil A flat plate is the simplest supersonic airfoil.
Since the flow across a shock wave is irreversible, the downstream state must have the higher entropy. The upstream state is supersonic and the downstream state is subsonic. Thus, shock waves can happen only in supersonic flow and the flow becomes subsonic once it crosses a shock wave.
No, because after a shock the flow changes from supersonic to subsonic.