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Kelvin-Helmholtz instability in an inviscid setting?

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    • Karthik R
      Administrator

      Hello,

      I'm reading about the Kelvin-Helmholtz instability. Can this instability occur in an inviscid setting?

      Thank you

    • Keyur Kanade
      Ansys Employee

      Hello, 

      You are absolutely correct. KH instability requires the following conditions: two uniform flow of different velocity and density that are incompressible and inviscid. The instability sets in when the following instability condition is met.

      (U1-U2)^2 > g(rho1^2 - rho^2)/(alpha * rho1 * rho2)

      where,

      alpha = 2*pi / lambda,

      lambda is the wavelength of the disturbance,

      subscript 1 and 2 refer to fluids 1 and 2.

      This instability manifests as roll-up vortices examples of which include the famous Jupiter's Red Spot and cloud formation.

      I hope this helps.

      Thank you.

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