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Oblique shockwaves

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  • Oblique shockwaves

    Hello,

    Just a principle question : It is shown in the course on high speed flight that the shockwave starts to bend when Mfs exceeds Mdet, around M1.3

    Therefore shouldn't the formula for the Mach angle be something like Sine (mu) = 1 / (1+Mfs-Mdet) ?

    If we consider a small Mfs like M1.1, the shockwave should not bend as Mdet is not exceeded, but the basic formula gives an angle of 65 already

  • #2
    The image in ATPdigital is a major simplification, showing only the part of the shockwave directly ahead of the nose.

    If you type Shell Oil Transonic Flight into YouTube you should get a 19min 58 second video. Between about 3mins and 4.15 mins you can observe the bigger picture of what happens to the bow wave as we accelerate from M1 to Mdet and beyond.
    A normal shock wave forms at Mach 1 and, apart from directly ahead of the nose, the shock wave immediately starts to turn oblique with increasing speed, and by Mdet it is significantly oblique.

    Despite probably dating from the 1950s, it is actually quite a helpful video.
    Searching instead for Shell High Speed Flight should bring up 3 similar ancient lessons covering the whole speed range......but you will need to have about an hour to spare to watch it all.

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    • #3
      Got it, thank you so much for the link !

      I love these vintage documentaries, clear explanation with simple graphical illustrations.
      These were well worth the time spent watching them.

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