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alpha.water boundary condition

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Old   January 18, 2022, 06:55
Default alpha.water boundary condition
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hello i am a beginner of openfoam!

i am studying the example related the water injection. in this situation, i have a question..


I set the water injection amount to change with time by using code as mentioned below.

(velocity(U) boundary condition)

Code:
boundaryField
{
    inlet1
    {

    type flowRateInletVelocity;
    volumetricFlowRate table
    (
        (0 2)
        (50 2)
        (50.01 0)
        (100 0)
        (100.01 2)
        (150 2)
        (150.01 0)
        (200 0)
        (200.01 2)
        (250 2)
        (250.01 0)
    );

    }
about the boundary condition of U in above code, what boundary condition will be suitable for alpha.water.orig ? i don't know which boundary condition to choose for alpha.water in this time varying boundary condition of U.

thank you !

Last edited by Tobi; January 18, 2022 at 07:56. Reason: Updated the formatting
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Old   January 18, 2022, 07:55
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Depending on the real case, you could switch alpha between 0 and 1, similar to your U condition. So if no flux is going into your domain, set alpha to 0 or apply a zeroGradient BC. For that you would need to integrate a codedMixed boundary condition and use a switch between Neumann and Dirichlet based on, e.g., the time data or the velocity values at the patch faces.
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