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Homework Help: Can anyone check this identity please?

  1. Sep 7, 2011 #1
    1. The problem statement, all variables and given/known data

    I just want to check if this identity is true, since I have not found it anywhere, can anyone help me?

    v is a vector (and that nu is supposed to be a v too)
     

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  2. jcsd
  3. Sep 7, 2011 #2

    LCKurtz

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    The "identity" only makes sense if one of the factors is a scalar, and it's wrong even then. I think you want this, where f is a scalar function and V is a vector function:

    [tex]\nabla \cdot f\vec V = \nabla f \cdot \vec V + f (\nabla \cdot \vec V)[/tex]
     
  4. Sep 7, 2011 #3
    I finally found it, looks like I was missing another term in the right side v(Div(v)), altough this is 0 in my case because im working with fluid dynamics. Now everything makes perfect sense, thanks anyway
     
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