supersonic Definition and Topics - 12 Discussions

Supersonic speed is the speed of an object that exceeds the speed of sound (Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level, this speed is approximately 343.2 m/s (1,126 ft/s; 768 mph; 667.1 kn; 1,236 km/h). Speeds greater than five times the speed of sound (Mach 5) are often referred to as hypersonic. Flights during which only some parts of the air surrounding an object, such as the ends of rotor blades, reach supersonic speeds are called transonic. This occurs typically somewhere between Mach 0.8 and Mach 1.2.
Sounds are traveling vibrations in the form of pressure waves in an elastic medium. In gases, sound travels longitudinally at different speeds, mostly depending on the molecular mass and temperature of the gas, and pressure has little effect. Since air temperature and composition varies significantly with altitude, Mach numbers for aircraft may change despite a constant travel speed. In water at room temperature supersonic speed can be considered as any speed greater than 1,440 m/s (4,724 ft/s). In solids, sound waves can be polarized longitudinally or transversely and have even higher velocities.
Supersonic fracture is crack motion faster than the speed of sound in a brittle material.

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  1. NatanijelVasic

    I Subsonic and Supersonic Airflow Through a Constriction

    Hi everyone! For the past week I have spend a lot of time thinking about how de Laval nozzles work. But before I convince myself that I have understood it, I want to make sure that the (simpler) scenarios I describe below are correct. Setup: We have a long pipe with constant radius r = 1...
  2. A

    B Supersonic rockets

    if you and your friend ride a supersonic rocket , do you can listen to your friend voice ? I mean if you travel faster than sound will you can hear anything ,It's difficult to imagine. And thanks so much,
  3. Algr

    Supersonic vs Suborbital planes?

    So I'm watching a documentary on supersonic flight, and the challenges they describe seem SO daunting that I couldn't help but wonder: Wouldn't it just be easier to fly above (most of) the atmosphere? There must be an altitude where sonic booms no longer reach the ground and wind pressure no...
  4. T

    I Supersonic wave travel question

    I've read somewhere that supersonic waves behave like supercritical flow of fluids and that subsonic waves behave similarly to that of subcritical flow. I guess an example of subcritical flow is pinching a hose and supercritical is how water flows over rocks (a bit more confused on that). Can...
  5. Thom_Silva

    Sound source moving at the speed of sound

    Hi, Suppose that a plane that is travelling at the speed of sound has a loudspeaker attached to it. Along the he trip the loudspeaker releases specific sounds. What does the pilot ear when the first sound is released? And after the second sound is released, does he ear both sounds at the same...
  6. 8eou8elisi

    Supersonic Flow Before and After the Shockwave

    After a Compression (Oblique) Shockwave during supersonic flight, the air speed (Mach number) is always reduced. I was wondering if an aerodynamic shape could be created to increase the speed of the affected stream to a Mach number greater than the freestream Mach number. I am looking for an...
  7. 8eou8elisi

    Pressure Impulses during Supersonic Flight

    Hey Everyone. I am new to this forum, so first of all greetings to everybody. What are your thoughts on the below idea..? Is it possible to make the pressure impulses created by a Supersonic Aircraft to travel faster than the speed of Sound? I know that the pressure impulses during a Supersonic...
  8. kelvin490

    How can shock waves travel faster than sound?

    Shock wave is caused by the disturbance of air by the airplane. When it propagate the mechanism should be the same as that of longitudinal sound wave. Why sometimes it can travel faster than sound? (also see: http://physics.info/shock/ )
  9. yangshi

    Choked flow out of air compressor and wind tunnels

    I posted this on Eng-tips and no replies yet:( I'm trying to design an as-simple-and-cheap-as-possible supersonic wind tunnel using an air compressor (this even possible? given the energy losses from shock waves...). I have access to a Porter-Cable 150psi, .8hp air compressor. Questions: 1...
  10. B

    Could we make a supersonic electric airplane?

    Hi guys, I've been reading a bit and watching a few youtube videos on electric aircraft, but have come across little to do with supersonic aircraft. As far as I understand it an electric aircraft would use basically fans to push air behind it and as such generate thrust. The problem would be...
  11. S

    Nozzle problem between subsonic and supersonic speed & nozzle area

    Hi all, I have really a confusion between subsonic and supersonic speed evolution when the area decrease or increase I have a problem to understand why in supersonic regime the velocity evolution in a nozzle is adverse of the subsonic regime? for example in subsonic regime, when the area...
  12. H

    Oblique Shock Angle

    Is there an equation to calculate the oblique shock angle for supersonic flow when the given angle of attack is greater than 0, but less than the half angle? In my particular practical experiment, the half angle of the aerofoil is 5 degrees, so want to get a variety of figures between 5 and -5...
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