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k-w model and y+ value and EWF(Eulerian wall film) with DPM

    • Micheal
      Subscriber

      Hello, I'm using EWF(Eulerian Wall Film) Model + DPM to express the particle deposition.

      If I consider only "stick" to the wall, I have some questions about that.(neglecting rebound, splash, etc)

      As fas as i know, stick phenomenon is depending on (Vpn)^2(main stream velocity normal to the wall) and fluid density, surface tension.. etc 

      Q. Do I need to make a fine mesh?(y+<1)

      • In my personal oppinion, EWF makes virtual cell layers automatically between first cell and the wall because it has tiny thickness(~1e-9m) that's why y+ is not important with k-w model and wall function.
      • Or Nevertheless, EWF needs strict criteria of fine mesh(y+<<1) because thin film phenomenen is also depending on the particle flow near the wall

       

    • Rob
      Forum Moderator

      Not a simple question, and something to ponder. 

      If I set y+ = 1 how high is my first cell layer. How thick is the film? If the film is thicker than the cell (or thick relative to the cell height) is the thin film assumption correct? 

      If I have a coarse near wall cell, how good is the particle trajectory calculation and/or velocity value taken by the film? 

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