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Calculates propeller performance and wake field properties.

Controlled by executeControl:

• Propeller performance
  • Thrust coefficient, Kt
  • Torque coefficient, 10*Kq
  • Advance coefficient, J
  • Open water efficiency, etaO
  • Written to postProcessing///propellerPerformance.dat

Controlled by writeControl:

• Wake field text file
  • Wake: 1 - UzMean/URef
  • Velocity in cylindrical coordinates at xyz locations
  • Written to postProcessing///wake.dat
• Axial wake field text file
  • 1 - Uz/URef at r/R and angle
  • Written to postProcessing///axialWake.dat
• Velocity surface
  • Written to postProcessing//surfaces/time>/disk.

Example wake field - Courtesy of Yannick Eberhard, Promarin GmbH

Usage

Example of function object specification:

propellerInfo1
{
    type            propellerInfo;
    libs            (forces);
    writeControl    writeTime;

    patches         ("propeller.*");

    URef            5; // Function1 type; 'constant' form shown here
    rho             rhoInf; // incompressible
    rhoInf          1.2;

    // Optionally write propeller performance data
    writePropellerPerformance yes;

    // Propeller data:

    // Radius
    radius          0.1;

    rotationMode    specified; // specified | MRF

    // rotationMode = specified:
    origin          (0 -0.1 0);
    n               25.15;
    axis            (0 1 0);

    // Optional reference direction for angle (alpha) = 0
    alphaAxis       (1 0 0);

    //// rotationMode = mrf
    //// MRF             MRFZoneName;
    //// (origin, n and axis retrieved from MRF model)

    // Optionally write wake text files
    // Note: controlled by writeControl
    writeWakeFields yes;

    // Sample plane (disk) properties
    // Note: controlled by writeControl
    sampleDisk
    {
        surfaceWriter   vtk;
        r1              0.05;
        r2              0.2;
        nTheta          36;
        nRadial         10;
        interpolationScheme cellPoint;
        errorOnPointNotFound false;
    }
}

Where the entries comprise:

Property	Description	Required	Deflt value
type	Type name: propellerInfo	yes
log	Write to standard output	no	no
patches	Patches included in the forces calculation	yes
p	Pressure field name	no	p
U	Velocity field name	no	U
rho	Density field name	no	rho
URef	Reference velocity	yes
rotationMode	Rotation mode (see below)	yes
origin	Sample disk centre	no*
n	Revolutions per second	no*
axis	Propeller axis	no*
alphaAxis	Axis that defines alpha=0 dir	no
MRF	Name of MRF zone	no*
originOffset	Origin offset for MRF mode	no	(0 0 0)
writePropellerPerformance	Write propeller performance text file	yes
writeWakeFields	Write wake field text files	yes
surfaceWriter	Sample disk surface writer	no*
r1	Sample disk inner radius	no	0
r2	Sample disk outer radius	no*
nTheta	Divisions in theta direction	no*
nRadial	Divisions in radial direction	no*
interpolationScheme	Sampling interpolation scheme	no*	cell

Note

• URef is a scalar Function1 type, i.e. supports constant, table, lookup values
• rotationMode is used to set the origin, axis and revolutions per second
  • if set to specified all 3 entries are required
    • note: origin is the sample disk origin
  • if set to MRF only the MRF entry is required
    • to move the sample disk away from the MRF origin, use the originOffset
• if writePropellerPerformance is set to on|true:
  • propellerPerformance text file will be written
• if writeWakeFields is set to on|true:
  • wake and axialWake text files will be written
• if the surfaceWriter entry is set, the sample disk surface will be written
  • extents set according to the r1 and r2 entries
  • discretised according to the nTheta and nRadial entries

Note: sign-off in EP 1719