Should I use a pressure-based solver or a density-based solver for two different inlet types?

abd fsabd fs Member Posts: 159

Dear researchers, I want to simulate a flow (air) in a wind tunnel, and I want to integrate a fluidic actuator inside it in order to control the separation of the boundary layer. At the blower inlet a velocity of 30m / s is imposed and at the inlet of the fluidic actuator of 0.3 MPa is imposed. My question are:

should I use Pressure Based Solver or a Density-Based Solver?

Best Answer

Answers

  • YasserSelimaYasserSelima Member Posts: 431

    If your Mach numbers are less than 0.3, use the Pressure-based solver.

  • KremellaKremella Admin Posts: 2,326

    Hi,

    What kind of Mach numbers are you expecting to investigate? If you are working in strong supersonic or hypersonic flow regimes, I might use the density-based solver.

    Based on your question, this does not seem like the case. The pressure-based solver in Fluent is quite capable of handling mild to strong compressibility effects. I'd use this in your problem.

    Karthik

  • abd fsabd fs Member Posts: 159

    Dear researchers, thank you for your quick responses.

    The purpose of adding a fluidic actuator is to change the turbulent boundary layer. For more information about my work, I have divided my work plan into three stages.

    firstly I did a detailed study on the fluid actuator where I used a Based -density solver tool with ideal gas as the oscillator offers high velocity of 130m / s and an oscillation frequency of 298 Hz The results are in good agreement with the experimental results.

    Second, I am simulating turbulent flow in a wind tunnel using a Based-pressure solver with air as a liquid, and the results agree well with the experimental experience.

    Now I want to unify the geometric shapes with each other as shown above.

    1- Should I use the ideal air or gas?

    2- Should I use a pressure-based converter or a density based converter?

  • KremellaKremella Admin Posts: 2,326

    Hi,

    1. If your flow is compressible, use the Ideal Gas Law to model air.
    2. I think you should be able to use the pressure-based solver. Based on the velocity scales, the flow seems midly compressible.

    Karthik

  • abd fsabd fs Member Posts: 159

    Dear Kremella thank so much for your inspiring answers.

    Am I allowed to use air as a fluid with the Based-density solver?

    Best regard,

    SERRAR

  • KremellaKremella Admin Posts: 2,326

    Hello,

    Yes, you should be able to use air. There are no such restrictions as long as you keep the density of the fluid floating.

    Karthik

  • abd fsabd fs Member Posts: 159

    Dear Kremella,

    1- what do you mean by keeping the density of the fluid floating?

    2- how can I check this condition?

    Best regards,

    SERRAR

  • RobRob UKForum Coordinator Posts: 8,371

    If the material is compressible you need to model it as such, ie above about 0.3M use ideal gas density.

  • abd fsabd fs Member Posts: 159

    Dear Rob,

    the simulation of a turbulent flow in a wind tunnel at a velocity of 20m / s equivalent to 72km / h, is similar to a simulation around a flow around a vehicle so the flow is incompressible. However, the problem arises when adding the actuator which is supplied by a pressure of 0.3 MPa and a Mach number equal to 0.45 at its output.

    Best Regads,

    SERRAR

  • KremellaKremella Admin Posts: 2,326
    Accepted Answer

    Please use the Ideal gas law for material density. Also, use the Pressure-Based solver.

    Karthik

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