Supersonic flow and Supersonic flow and shockwavesshockwaves

Claude-Louis NavierGeorge Gabriel Stokes

Supersonic flow and Supersonic flow and shockwavesshockwaves• Mach Number: M = u/cMach Number: M = u/c

- u speed object- u speed object- c constant speed of sound- c constant speed of sound- Ersnt Mach, physicist who - Ersnt Mach, physicist who

studied gas studied gas dynamicsdynamics• Properties of the flowProperties of the flow

• PressurePressure• VelocityVelocity• TemperatureTemperature• DensityDensity

• ThermodynamicsThermodynamics• Normaly an isentropic flowNormaly an isentropic flow

Enrst Mach

Supersonic flow and Supersonic flow and shockwavesshockwaves

• Two main factors that contribute to the Two main factors that contribute to the flow over an objectflow over an object

•ViscosityViscosity

•Compressibility factorCompressibility factor

• To describe the flow of gas we use To describe the flow of gas we use the Navier-Stokes equationsthe Navier-Stokes equations

Supersonic flow and Supersonic flow and shockwavesshockwaves

Equation of continuityCompressible fluid Imcompressible fluid

Equation of conservation of momentum

Equation of conservation energy

Supersonic flow and Supersonic flow and shockwavesshockwaves

• Types of flowTypes of flow•Subsonic flow (M<1)Subsonic flow (M<1)

•Transonic flow (around M=1)Transonic flow (around M=1)

•Supersonic flow (M>1)Supersonic flow (M>1)– Hypersonic flow (M>5)Hypersonic flow (M>5)

Supersonic flow and Supersonic flow and shockwavesshockwaves

• Subsonic flowSubsonic flow– Ignore Ignore

Compressibility Compressibility factor below M<0.3factor below M<0.3

– Viscocity must be Viscocity must be taken into accounttaken into account

– Incompressible flowIncompressible flow

Lockheed C-130 Hercules (Mach 0.5)

Schweitzer 2-33A Glider (Mach 0.07)

Supersonic flow and Supersonic flow and shockwavesshockwaves

• Transonic flowTransonic flow– Compressibility Compressibility

factor and viscocity factor and viscocity of the fluid must be of the fluid must be taken into accounttaken into account

– Increase in drag Increase in drag and not a stable and not a stable speed to fly inspeed to fly in

– Shockwaves start to Shockwaves start to appearappear

Bell X-1 (Mach 1) October 14th,1947Chuck Yeager

Supersonic flow and Supersonic flow and shockwavesshockwaves

• Supersonic flowSupersonic flow– Must take Must take

compressibility into compressibility into accountaccount

– Viscosity can be Viscosity can be neglectedneglected

– Shockwaves are Shockwaves are createdcreated

SR-71 Blackbird (Mach 3.2)

Supersonic flow and Supersonic flow and shockwavesshockwaves

• Hypersonic flow Hypersonic flow (above Mach 5)(above Mach 5)

• Aerodynamic Aerodynamic heating occurs heating occurs (caused by friction (caused by friction and compression)and compression)

• Compressible flowCompressible flow

X-15 (Mach 10)

Supersonic flow and Supersonic flow and shockwaveshockwave• SonicboomSonicboom

• Caused by an object Caused by an object breaching the speed of breaching the speed of soundsound

• Object continously Object continously produces air-pressure produces air-pressure waves.waves.

• The actual sound is The actual sound is created by the sudden created by the sudden offset of the release of offset of the release of the pressure waves.the pressure waves.

• Sound BarrierSound Barrier

Supersonic flow and Supersonic flow and shockwavesshockwaves• ShockwavesShockwaves

• Occurs as the Occurs as the airplane compresses airplane compresses air molecules faster air molecules faster than they can move than they can move away from the away from the airplane. airplane.

• Biggest concern Biggest concern when it comes to when it comes to supersonic flightsupersonic flight

• Can be harmful to Can be harmful to humans and animals humans and animals even after the even after the shockwaves have shockwaves have decayeddecayed

Supersonic flow and Supersonic flow and shockwavesshockwaves

Supersonic flow and Supersonic flow and shockwavesshockwaves

Supersonic flow and Supersonic flow and shockwavesshockwaves

• Space shuttle has to Space shuttle has to reach a vertical reach a vertical speed of Mach 25 to speed of Mach 25 to to be able to reach to be able to reach orbit.orbit.

• Cheaper more Cheaper more efficient ways of efficient ways of getting to space are getting to space are being developed being developed everywhereeverywhere

Supersonic flow and Supersonic flow and shockwavesshockwaves

• Future Future developmentsdevelopments

• Low shockwave Low shockwave emission aircraftemission aircraft

• Faster airplanesFaster airplanes

• Cheaper ways of Cheaper ways of getting to spacegetting to space

• New designs for New designs for supersonic transport supersonic transport aircraftaircraft

Supersonic flow and Supersonic flow and shockwavesshockwaves

The endThe end