OpenFOAM v14 User Guide

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6.2 Field sources

Field sources, speciﬁed by the optional sources entry in ﬁeld ﬁles, relate to cases which include a mass or volume source that introduces ﬂuid at some internal region of the domain. A good example to demonstrate ﬁeld sources is damBreakInjection, which is an extension of the damBreakLaminar tutorial from section 2.2 . The case can be run by the following commands.

    run
    cp -r $FOAM_TUTORIALS/incompressibleVoF/damBreakInjection
    cd damBreakInjection
    ./Allrun

Note that the case originally only contains ﬁles with the additional entries from the damBreakLaminar case. The Allrun script executes the foamMergeCase script to merge the original ﬁles from the damBreakLaminar case, before meshing and running the simulation. The ﬁrst main addition in damBreakInjection case is an fvModel deﬁned in constant/fvModels, reproduced below.

    injection
    {
        type            volumeSource;
        phase           water;
        cellZone
        {
            type            containsPoints;
            points          ( (0.438 0.438 0.0073) );
        }
        volumetricFlowRate 0.0003;
    }

This volumeSource model injects water at a volumetric ﬂow rate of 0.0003 $\text{[math]}$ within a deﬁned cell zone consisting of a single cell. When such a model is applied, some ﬁeld values for the injected ﬂuid must be speciﬁed, e.g. its velocity. The sources entries enable this by including them in the ﬁelds that require values. For the damBreakInjection, the velocity of the injected ﬂuid is speciﬁed by a sources entry in the U ﬁle which is reproduced below.

    sources
    {
        injection
        {
            type            uniformFixedValue;
            uniformValue    (-1 0 0);
        }
    }

Through the common name of the model, i.e. injection, the entry corresponds to the volumeSource model in the fvModels ﬁle. The velocity is speciﬁed as a uniformFixedValue condition with a value of (-1 0 0). The resulting injection is shown in an image of phase fraction below, displays the phase fraction alpha.water in each cell.

$PICT\relax \special {t4ht=$

Figure 6.4: damBreak with an injection source upper right.

The water is injected in the upper right quadrant of the image, in the cell which is red, corresponding to alpha.water = 1. It initially follows a path in the negative $\text{[math]}$ direction, from right to left, according to the direction speciﬁed in the sources entry. But soon afterwards, gravity causes the injected water to move downward, i.e. from top to bottom in the image.

OpenFOAM v14 User Guide - 6.2 Field sources

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OpenFOAM v14 User Guide - 6.2 Field sources

What are field sources in OpenFOAM?

6.2 Field sources