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Added ramping functionality for multiphase simulations

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The outletPhaseMeanVelocity and waveVelocity boundary conditions now
support a "ramp" keyword, for which a function can be supplied to
gradually increase the input velocity. The following is an example
specification for an outlet patch:

    outlet
    {
        type            outletPhaseMeanVelocity;
        Umean           2;
        ramp
        {
            type            quarterSineRamp;
            start           0;
            duration        5;
        }
        alpha           alpha.water;
    }

There is also a new velocityRamping function object, which provides a
matching force within the volume of the domain, so that the entire flow
is smoothly accelerated up to the operating condition. An example
specification is as follows:

    velocityRamping
    {
        type        velocityRamping;
        active      on;
        selectionMode all;
        U           U;
        velocity    (-2 0 0);
        ramp
        {
            type        quarterSineRamp;
            start       0;
            duration    5;
        }
    }

These additions have been designed to facilitate a smoother startup of
ship simulations by avoiding the slamming transients associated with
initialising a uniform velocity field.

This work was supported by Jan Kaufmann and Jan Oberhagemann at DNV GL.
This commit is contained in:
Will Bainbridge
2018-01-08 08:50:07 +00:00
parent 9a35ce69a3
commit a80da1a489
10 changed files with 408 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
applications/utilities/preProcessing/setWaves/setWaves.C
View File

@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2017 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2017-2018 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
@ -72,6 +72,7 @@ int main(int argc, char *argv[])
forAll(timeDirs, timeI)
{
runTime.setTime(timeDirs[timeI], timeI);
const scalar t = runTime.value();
Info<< "Time = " << runTime.timeName() << nl << endl;
@ -188,17 +189,16 @@ int main(int argc, char *argv[])
}
liquid = liquidp;
const scalar t = runTime.value();
const pointField& ccs = mesh.cellCentres();
const pointField& pts = mesh.points();
// Internal field superposition
h.primitiveFieldRef() += waves.height(t, ccs);
hp.primitiveFieldRef() += waves.height(t, pts);
uGas.primitiveFieldRef() += waves.UGas(t, ccs) - waves.UMean();
uGasp.primitiveFieldRef() += waves.UGas(t, pts) - waves.UMean();
uLiq.primitiveFieldRef() += waves.ULiquid(t, ccs) - waves.UMean();
uLiqp.primitiveFieldRef() += waves.ULiquid(t, pts) - waves.UMean();
uGas.primitiveFieldRef() += waves.UGas(t, ccs) - waves.UMean(t);
uGasp.primitiveFieldRef() += waves.UGas(t, pts) - waves.UMean(t);
uLiq.primitiveFieldRef() += waves.ULiquid(t, ccs) - waves.UMean(t);
uLiqp.primitiveFieldRef() += waves.ULiquid(t, pts) - waves.UMean(t);
// Boundary field superposition
forAll(mesh.boundary(), patchj)
@ -206,9 +206,9 @@ int main(int argc, char *argv[])
const pointField& fcs = mesh.boundary()[patchj].Cf();
h.boundaryFieldRef()[patchj] += waves.height(t, fcs);
uGas.boundaryFieldRef()[patchj] +=
waves.UGas(t, fcs) - waves.UMean();
waves.UGas(t, fcs) - waves.UMean(t);
uLiq.boundaryFieldRef()[patchj] +=
waves.ULiquid(t, fcs) - waves.UMean();
waves.ULiquid(t, fcs) - waves.UMean(t);
}
++ nWaves;
@ -246,7 +246,8 @@ int main(int argc, char *argv[])
const waveSuperposition& waves =
refCast<const waveVelocityFvPatchVectorField>(Up).waves();
UMean == dimensionedVector("UMean", dimVelocity, waves.UMean());
UMean ==
dimensionedVector("UMean", dimVelocity, waves.UMean(t));
}
}
else if (nWaves > 1)
@ -290,7 +291,7 @@ int main(int argc, char *argv[])
weight += w;
weightUMean +=
w*dimensionedVector("wUMean", dimVelocity, waves.UMean());
w*dimensionedVector("wUMean", dimVelocity, waves.UMean(t));
}
// Complete the average for the mean velocity