[piR]

Hi all,

I am quite new in the OpenFOAM world. I am trying to compute a Stokes 2 wave, which propagates along x<0 in a 3D domain. I use the interFoam solver of OpenFOAM-6.

I already got some results without damping zone at outlet and by initializing the wave in the whole domain. Of course this leads to a lot of reflections from this boundary. Before tackling the problem of body forces I want first to add a ramp-up time to the wave propagation, in order to see it moving from inlet to outlet.

I tried to use the following inlet boundary condition in U.orig:

    inlet
    {
        // https://cpp.openfoam.org/v6/waveVelocityFvPatchVectorField_8H_source.html
        type            waveVelocity;
        origin          (18.0145 7.50604166667 0); // origin of the wave coordinate system
        direction       (1 0 0); // direction of the mean flow
        speed           2.6034; // speed of the mean flow
        waves
        (
            Stokes2
            {
                length      5.147;
                amplitude   0.081;
                phase       0;
                angle       3.141593; // 180 deg = 3.141593 rad
            }
        );
        // ramp
        // {
        //     type        linearRamp;
        //     start       0;
        //     duration    1.977;
        // }
        scale       table ((-18.0145 0) (18.0145 0)); // From outlet to inlet set: 0
        crossScale  constant 1;
    }

I noticed that if the speed is 0, the solution crashes giving an invalid pointer issue. If I understood well, it is a kind of division by 0, however we should have the possibility to set no mean flow, i.e. no current.
I also noticed that using the scale function totally flattens the waves.

So, my questions are:

1. Is a ramp-up time possible in OpenFOAM-6 to control the propagation of the wave?
2. Is the use of the scale function correct for this purpose? If not, how can I reach such a result?
3. Why does setting 0 speed lead to an invalid pointer issue?

Do not hesitate to ask me if you need more information.
Thanks in advance for any ideas!

Pierre

[Virag]

Did you get any clarification on this?