forceCoeffs.md

forceCoeffs

Class

Foam::functionObjects::forceCoeffs

Group

grpForcesFunctionObjects

Description

This function object extends the Foam::forces function object by providing lift, drag and moment coefficients. The data can optionally be output into bins, defined in a given direction.

Example of function object specification:

forceCoeffs1
{
        type        forceCoeffs;
        libs ("libforces.so");
        ...
        log         yes;
        patches     (walls);
        liftDir     (0 1 0);
        dragDir     (-1 0 0);
        pitchAxis   (0 0 1);
        magUInf     100;
        lRef        3.5;
        Aref        2.2;

        binData
        {
            nBin        20;
            direction   (1 0 0);
            cumulative  yes;
        }
}

Usage

    Property     | Description             | Required    | Default value
    type         | type name: forces       | yes         |
    log          | write force data to standard output | no | no
    patches      | patches included in the forces calculation | yes |
    liftDir      | lift direction          | yes         |
    dragDir      | drag direction          | yes         |
    pitchAxis    | picth axis              | yes         |
    magUInf      | free stream velocity magnitude | yes  |
    lRef         | reference length scale for moment calculations | yes |
    Aref         | reference area          | yes |

Bin data is optional, but if the dictionary is present, the entries must be defined according o

    nBin         | number of data bins     | yes         |
    direction    | direction along which bins are defined | yes |
    cumulative   | bin data accumulated with incresing distance | yes |

See also

Foam::functionObject Foam::functionObjects::timeControl Foam::functionObjects::forces

SourceFiles

forceCoeffs.C