What is Supersonic: Definition and 77 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. A

    Supersonic and hypersonic shockwave mitigation

    The main reason supersonic flight is inefficient is because of the shockwave. The shockwave is caused by the inability of air to escape the path of the aircraft in time. As a result, the air builds up in front of the aircraft and a shockwave is formed. To try to reduce this effect, can't we add...
  2. Astronuc

    J58 jet engine and supersonic flight

    We've had several threads on the SR-71 (and related craft) and the J58 propulsion system. https://www.physicsforums.com/threads/sr-71-blackbird-supersonic-aircraft.68694/ https://www.physicsforums.com/threads/j-58-engine-inlet-spike.413262/...
  3. N

    What is necessary for a hypothetical supersonic speed Radio Controlled Jet?

    Hi everyone! :) While i watched rc jet exhibitions on youtube, i find that the most fast of this RC reached +700 Km/h. When i browse more information about the tourbine, i realized that for a hypothetical supersonic RC the mechanical system of the tourbine must have a complete air compressor...
  4. M

    Drag on a Supersonic Baseball (from SmarterEveryDay)

    In a recent video from SmarterEveryDay, a baseball is launched from an air cannon faster than the speed of sound. I used the video with my 2nd year HS physics class, and we put the high speed segment of the moving ball into Tracker (video analysis and modeling tool). We found that the drag...
  5. mfb

    NASA NASA is going to assemble a quiet supersonic aircraft: X-59 QueSST

    Press release The Concorde could only fly supersonic while over the open ocean - the sonic boom was too loud. NASA is looking for aircraft designs that are much quieter. While the X-59 itself isn't very practical for passenger transport it might have some direct military applications and help...
  6. X

    SpaceX Supersonic electric propulsion systems for airliners

    Tesla+SpaceX= supersonic VTOL suborbital electric jet? “I have an idea for a vertical takeoff and landing supersonic jet.” — Elon Musk, every time the subject of electric planes comes up, to include almost never using the VTOL abbreviation for some reason that’s probably very unimportant. —...
  7. Spinnor

    NASA NASA Captures First Air-to-Air Images of Supersonic Shockwave

    https://www.nasa.gov/centers/armstrong/features/supersonic-shockwave-interaction.html “We never dreamt that it would be this clear, this beautiful.” Physical Scientist J.T. Heineck of NASA’s Ames Research Center in Mountain View, California gets his first glimpse at a set of long-awaited...
  8. 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...
  9. T

    At supersonic speed, why does Mach number decrease?

    At supersonic speed, air become compressible. However why does Mach number decrease when flow area decrease? I understand that pressure will increase because the density will increase when flow area decrease. However shouldn't the Mach number increase in order to conserve mass flow? Unless the...
  10. A

    B Ride a Supersonic Rocket: Can You Hear Your Friend?

    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,
  11. 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...
  12. D

    Shockwave of mushroom cloud rising at supersonic speed

    I'm modelling the Hiroshima nuclear explosion on a real time real scale physics simulator. My initial simulations based on data accumulated from wikipedia such as temperature of the fireball the radius of it and using air pressure and air density data based on the detonation height of 600m has...
  13. D

    What formulas should I use to calculate drag for a supersonic bullet?

    I'm a computer scientist currently developing projectile simulators. My software will factor in drag coefficients of various shaped projectiles as well as gravity, air pressures, air density and temperatures at various heights. I am familiar with the drag formula but it's only useful up to Mach...
  14. Astronuc

    Can supersonic flight be quiet?

    Quiet supersonic flight is an intriguing idea. Is it possible? We'll see perhaps this year. I'd be curious about the cabin noise, as well as the external noise. Spike Aerospace expands quiet supersonic aircraft development Engineering is on track for a first flight of a subsonic prototype of...
  15. G

    Isothermal Expansion of Supersonic Flow

    Hi, In a standard converging-diverging rocket nozzle, we have (ex.) the relation:(1-M^2)\frac{dV}{V}=-\frac{dA}{A}By substituting in definitions, we can obtain\left(1-\frac{V^2}{\gamma R T}\right)\frac{dV}{V} = -\frac{dA}{A}This shows the dependence on temperature. The relation assumes that...
  16. andrewkirk

    Can we hear a supersonic plane?

    A very clever first-year physics student I know, who had just been learning about the Doppler effect, asked me a question. If a plane were flying a straight trajectory at Mach 2, playing a song on its speakers very loudly, and an observer with incredibly sensitive recording equipment were to...
  17. 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...
  18. S

    Where Does the Normal Shock Occur in a Supersonic CD-Nozzle?

    Homework Statement Hi everybody! I have a question about this type of flow. I have a Convergent divergent passage, with supersonic flow upstream and downstream, the flow iside of it is unknowm. The question is that , knowing that one normal shock occurs within the canal, either in the...
  19. Thom_Silva

    Sound source moving at the speed of sound

    Hi, Suppose that a plane that is traveling 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...
  20. M

    Determine supersonic flow velocity, tank to regulator topipe

    Hello All, I am trying to figure out the solution to a problem I am trying to do for fun. I've been trying this for a while and has annoyed me so any help is greatly appreciated! I attached a picture of the problem/ control area to help...
  21. 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...
  22. 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...
  23. S

    Continuous Supersonic Wind Tunnels

    Hi Readers, I have just began learning about a few types of supersonic wind tunnels. I am more concentrated on the continuous type where the air on the inside can be reused using coolers, fans, vanes, nozzles, diffusers, etc. But can someone give me a few types of these continuous supersonic...
  24. 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/ )
  25. 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...
  26. 2

    Supersonic wave and distance calculation

    To calculate the distance from a stationary visible object using the speed of sound when dealing with a supersonic blast wave from that object, how would one proceed? Is the standard 340m/s good enough reference? How is the velocity reduction over time and distance? Does all the variables...
  27. kroni

    Can a Bow Launch an Arrow at Supersonic Speeds?

    Hello, I am asking if from your point of view, is it possible to build a bow that can lunch arrow to a supersonic speed (speed superior to 350 m/s) ? I make some calculus, estimating cinetic energy needed but, is it possible to build a bow where this energy can be obtained ? In which material ...
  28. S

    Difference between a subsonic Pitot tube and supersonic one

    Hi, Please could you explain the difference between a subsonic Pitot tube and supersonic one Thanks
  29. 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...
  30. 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...
  31. H

    Calc Oblique Shock Angle for Supersonic Flow 0-5 Degrees

    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...
  32. JasonGodbout

    Can Metamaterials Be Used to Reduce Shockwaves in Supersonic Flight?

    Could we use something like carpet cloaking to reduce shockwave in supersonic or mach wave in transonic flight? Student in mechanical engineering
  33. V

    Supersonic motion: no backward propagating shock waves

    There was a recent thread (now closed) where I claimed that a body accelerating beyond the speed of sound emits a shock wave that propagates spherically backward in the rear hemisphere. I have reviewed literature on fluid dynamics and it is quite clear to me now that I was wrong. There is no...
  34. V

    Can an IC Engine's Exhaust Flow Reach Supersonic Speeds?

    i wanted to know if the flow in the exhaust pipe of an ic engine cross the sonic speed? i have been seeing a lot of papers presented about the supersonic internal flows on the net and hence i wanted to know some of the practical situations where such flows can be seen?
  35. K

    Supersonic airplane emits a sound when right over a listener

    Hello, I'm having a bit of a problem with the following problem: A supersonic airplane flying at the velocity v is flying horizontally to the ground with altitude h. At the exact moment when the plane is vertically above a listener on the ground, it emits a sound. It takes Δt seconds for the...
  36. D

    Sound and supersonic motion - a question from Feynman's lectures

    Sound and supersonic motion -- a question from Feynman's lectures In chapter 51, volume 1 of the FLP, Feynman writes Unfortunately he didn't give a justification for this claim. I was hoping someone in Physics Forums could fill this gap in.
  37. H

    Audio Source Moving @ Supersonic Speed

    Let's say I have an indestructible speaker and I launch it out of a cannon at Mach 1.5 while it's playing music. (To make things simple, it also has an iPod and battery attached to it.) If the speaker passes a stationary observer, will they hear each cycle of the sound wave from the speaker in...
  38. P

    Supersonic Airfoil + Bow Shocks

    Homework Statement Hey all, In my Gas dynamics class we need to find the lift and drag coefficients of a supersonic airfoil (diamond shaped) for a range of AoA and Mach numbers. I can easily handle any situation where oblique shocks or Prandtl-Meyer expansions occur, but I'm unsure how to...
  39. V

    Supersonic ping pong ball cannon

    Video: Description: http://arxiv.org/ftp/arxiv/papers/1301/1301.5188.pdf So I though I would do a back-of-envelope check if that was even possible. I decided to model that as adiabatic expansion from the pressure plenum into the barrel, ignoring any effect the nozzle could make. So...
  40. S

    Supersonic plane at mach 3

    Homework Statement A supersonic plane flies at Mach 3 at an altitude of 20,000 m. A person on the ground sees the plane directly overhead. How much time passes the before she hears the sonic boom? Homework Equations f=fo(v+-vo/v-+vs) The Attempt at a Solution I don't really know...
  41. N

    Supersonic Flow in Diverging Nozzle

    Clearly, at low speeds the velocity of a fluid increases when the area through which it is traveling decreases. I am curious as to why a fluid traveling faster than the speed of sound increases its velocity when its area is increased. Thank you
  42. V

    Space Elevator: Magnitized Cable for Supersonic Travel

    Everyone has heard of the space elevator using a cable(s) that attaches to a geosynchronus satellite. Now trying to lift things is always a very energy expensive process, since just making a payload weightless cost energy and you get zero velocity and travel. Also how fast could an elevator...
  43. F

    Supersonic Flight: Lift & Pressure Differences

    Supersonic Lift? Lift appears to be from the angle of attack, due to the deflection of flow-stream in supersonic flight but then in subsonic flight the pressure difference causes lift. So what is going on here that i am missing? Why such a change? Its starting to confuse me.
  44. F

    Generating lift at supersonic speeds

    Im having some trouble understanding how lift is generated at supersonic speed as apposed to subsonic speed. Viscous effects at high speed are greatly reduced and a normal airfoil from subsonic flight is not suitable for such applications. I have had a good read on wiki and other sites but i...
  45. F

    Supersonic Flight: How Does Speed Impact Lift?

    Does traveling faster than the speed of sound affect how lift is generated?
  46. FtlIsAwesome

    Explore Physiology & Aerodynamics of Supersonic Alien Birds

    I am working on a scifi series. This question crosses both Aerodynamics and Exobiology topics. I thought it would be interesting to have a genus of nonsentient birdlike creatures on an alien planet and they can fly at supersonic speeds. What would the physiology of these creatures be? They...
  47. S

    Can vortex rings travel at supersonic speeds?

    After a bit of searching of scholarly text and investigations I have found myself unable to find the next piece of information. Can there exist a vortex ring which travels at supersonic speeds? Not as in the airflow within the vortex ring, there was a paper I was able to acquire about that...
  48. M

    What is the De Laval nozzle and how is it used in supersonic expansion?

    i am mechanical engineering students. i need help in design and construction of supersonic expansion nozzle. Please share me your Knowledge and Experience of supersonic expansion nozzle and technical hand books.
  49. P

    Supersonic ballistics is nonlinear right and not solvable exactly right?

    So I thought I would try to figure out the maximum distance of our 7.62x54 round. obviously I used F=ma and for resistance I used Fdrag=(mass of bullet*density of air*v^2)/ballistic constant. the v^2 terms makes the equation nonlinear and not exactly solvable right? also, the angle at which...
  50. S

    How do supersonic sources create sonic booms?

    Why do supersonic waves (when the source is faster than the wave) create sonic booms? I understand that when a source breaks the sound barrier and travels at the speed of its waves, the waves just build up at the front of the source and create a condensed sound of multiply sound waves added...