1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Speed of sound in vortical flows

  1. Apr 19, 2013 #1
    hi there

    I am currently working with linear flows and using a ultrasonic setup to determine the speed of sound in a linear gaseous flow. But I would like to know more about the speed of sound in a vortical flow. Unfortunately I haven't been able to find any good book with regard to my topic and was wandering anyone could offer a good book or paper to get me going

  2. jcsd
  3. Apr 19, 2013 #2


    User Avatar
    Science Advisor
    Gold Member

    In an ideal gas, the speed of sound is always [itex]a = \sqrt{\gamma R T}[/itex] where [itex]\gamma[/itex] is the ratio of specific heats, [itex]R[/itex] is the specific gas constant and [itex]T[/itex] is the static temperature. It doesn't matter if it is vortical or quiescent or anything else as long as it is an ideal gas in this case.
  4. Apr 20, 2013 #3


    User Avatar
    Gold Member

    “Wave Equation for Sound in Fluids with Vorticity”

    We use Clebsch potentials and an action principle to derive a closed system
    of gauge invariant equations for sound superposed on a general background
    flow. Our system reduces to the Unruh (1981) and Pierce (1990)
    wave equations when the flow is irrotational, or slowly varying. We illustrate
    our formalism by applying it to waves propagating in a uniformly rotating
    fluid where the sound modes hybridize with inertial waves.”
  5. Apr 20, 2013 #4


    User Avatar
    Science Advisor
    Gold Member

    Assuming you have an ideal gas and can treat it as a continuum, there is no need to set up a wave equation and Clebsch potentials (of which I am only vaguely familiar) in order to determine the speed of sound at a given point in a gas.

    Of course me being me, now I am on a quest to figure out why the authors required a more complicated formulation like in the linked paper. They didn't really explain when and why you would need that in the paper and I don't have time to dig any further at the moment, but I am quite curious. The authors seem mostly interested in vorticity in superfluids, and I doubt that applies all that well to the OP's question, though I guess it might.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Speed of sound in vortical flows
  1. Speed of Sound (Replies: 3)

  2. Speed of sound (Replies: 17)