Backflow in Domain

KgpNiko16KgpNiko16 Member

suppose i have backflow in my domain at pressure outlet ,

so is there any method to determine the backflow turbulence quantities like intensity and all ?

Will solution general flow field be susceptible to these backflow  quantities ?

How to approach modelling backflow in domain provided i am no position to increase domain length to negate this backflow to forward flow only. ? If not possible then how much minimum length increase is required , is there any method to quantify ?

 

Comments

  • edited June 1

    Hello, 

    Can you elaborate on 'determine the backflow turbulence quantities like intensity and all?' If you mean is there a way to specific them, then yes. In the outlet boundary condition, you can specify the turbulence conditions, incase there is backflow. If you mean to check the values, then you can use contour plots/xy plots or surface definitions to get the quantitative values of the any field-variables on the outlet. 

    If there is a backflow, then yes, the entire flow-field will get affected. Any boundary conditions, especially outlet BC's work best when placed in a 'uniform flow'. So, the recommendation is to always change (move further) the location of the outlet. As for how far to move, it depends on the uniformity of the flow. Look for a location where the flow settles down and does not experience large gradients. 

    Thanks, 

    Kalyan

     

  • KgpNiko16KgpNiko16 Member
    edited June 1

    Thanks for your reply and sharing the tips,

    But my question means that while simulation setup how to choose values / ranges  for backflow quantities.  Is there any formulae based on upstream flow properties to find the first guess or do we need to hit and trial , if hit and trial then on what merit one should fix the values.

     

    Okay i will extend my domain... !

  • edited June 1

    Hello, 

    The specification of backflow quantities depends entirely on the problem at hand. The best way to go about specifying values at the outlet (in case of a backflow) would be to think of it as a inlet. 

    Please mark the appropriate answer as 'Is Solution' so that it can help others. 

    Thanks,

    Kalyan

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