Which momentum equation for porous media is correct?

GuojunGuojun Member Posts: 5

Hello everyone,

Through checking out the momentum equations for porous media from the user’s guide in Fluent 6.2, 16.1, 19R3, I found out that the viscous and inertial force terms in the equations are different. And the user’s guides all mention that all the equations are using the physical velocity formulation, so could you help me to explain why they are different, and which equation is correct? The attached are the momentum equations.

6.2


16.1


19R3


In addition, when the same viscous coefficient and inertial coefficient are loaded into the model through UDF, and all the settings in the models are same, however, the results are far different by using Fluent 16.1 and 19R3. I guess this difference is related to the momentum equation. Thanks in advance.

Answers

  • KremellaKremella Posts: 2,471Admin

    Hello,

    Fluent undergoes continuous improvement and what you are seeing is an artifact of this development cycle. As new features are added, some of the old capabilities are also enhanced. These improvements range from redefining the User Experience to modifying some solver capabilities. I'd strongly recommend that you use the latest version when you run your simulations.

    Thank you.

    Karthik

  • GuojunGuojun Posts: 14Member

    Hello Kremalla,

    Thanks for your reply. But I doubt that the differences between these equations are only caused by the development of Fluent. In Fluent 19R3, when the viscous resistance coefficient and inertial resistance coefficient are additionally multiplied with phase volume fraction and the squared of phase volume fraction, respectively. The results obtained by Fluent 16.1 and Fluent 19R3 are same. Do you mind explaining why? Thank you very much.

    Guojun

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