Fluids

Fluids

Pressure drop fluctuates

    • btingthewind
      Subscriber

      Dear you,

      Now I am doing a steady state simulation in Fluent with pressure based solver.

      Boundary condition:

      Velocity inlet (Velocity 10 m/s, Reynolds number 4000), pressure outlet, and other sides are periodic and symmerty.

      Mesh quality:

      Minimum orthogonoal 0.2.

      Turbulence model:

      RNG ke with enhanced wall treatment.

      Pressure drop is defined as:

      Static pressure of (the inlet - outlet).


      My question is:

      Why the pressure drop fluctates in a sinoidal pattern with in a range of 2 Pa, even the residuals of continuity and so on below 1e-5?


      BEST REGARDS

    • Murari Iyengar
      Ansys Employee
      Hi btingthewind This could happen due to a couple of reasons.
      High mesh skewness/aspect ratio: Please look through Chapter 22: Improving the Mesh (ansys.com).
      Incorrect model: Maybe K-e is not the correct model for your simulation. Try other turbulence models. Also, the Re is 4000 which indicates a mix of laminar and turbulent flow (I'm assuming you are doing internal flow). This could also be a reason for fluctuating residuals since the flow might not be steady.
    • Rob
      Ansys Employee
      Please can you post some images? Depending on the pressure 2Pa could be near enough zero change or huge.
    • btingthewind
      Subscriber
      Many thanks to you!!
    • btingthewind
      Subscriber
      Many thanks to you!!

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