Is it possible to have a Mach number greater than 1 at the throat?

  1. I have a problem for my Gas Dynamics homework, in which the problem asks to solve for the Mach number at the throat of a converging-diverging nozzle.

    I assumed that the Mach at the throat should be equal to 1 since the professor said it was impossible to have a Mach number greater then 1 at the throat.

    After showing the same problem to a Graduate Student I work with he showed me that it is possible to have a Mach number greater then 1 at the throat through the area ratios.

    But after speaking to my professor a second time he has again said it is not possible.

    So my question is.. is it possible to have a Mach number greater than 1 at the throat.


    Oh the conditions for the problem are as follows:
    Mi=2
    Ai=20 cm^2

    Athroat=15cm^2

    Shock Area=22 cm^2
    Ae=25cm^2

    where gamma= 1.4

    according to the solutions Mach at the throat equals 1.662


    I assumed it was 1 but it was not correct.


    If someone could steer me in the right direction I'd appreciate it thanks!
     
  2. jcsd
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