Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Fluid Mechanics Viscous Dissipation

  1. Nov 26, 2014 #1
    I am trying to find an expression for viscous dissipation for burger's vortex Velocity field which only has velocity component in the V theta direction. I'm confused as to which equation for viscosity dissipation is correct. I am seeing a lot of different things tau:S, tau:delV..which one is correct?

    Thanks!
     
  2. jcsd
  3. Nov 26, 2014 #2
    Um.. I think you need to be a bit more specific. What form are you working with?
     
  4. Nov 26, 2014 #3
    cylindrical coordintates....so this is what the velocity field is
    upload_2014-11-26_18-20-1.png
    what I am confused about is what exactly is the equation for viscous dissipation ... My professor said in class that it is 2muS:S (from Navierstokes eq.3) but I am seeing differen things online and I also heard from another classmate of mine that it has something to do with Sxtau components. Im just confused ....sorry if Im confusing the matter here.
     
  5. Dec 2, 2014 #4
    If S is the rate of deformation tensor (which it certainly appears to be), then:
    S = (∇V+∇VT)/2
    and
    τ = 2μS
    So, the rate of viscous dissipation is τ:∇V = τ:S = 2μS:S. All the relations you wrote are the same, and should give the same results.

    Chet
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Fluid Mechanics Viscous Dissipation
  1. Fluid mechanics (Replies: 3)

Loading...