Properties🔗
- The
actuationDiskSource
applies sources on velocity, i.e.U
, to enable actuator disk models for aero/hydro thrust loading of rotary disks (e.g. propellers, horizontal-axis wind/tidal turbines, or helicopter rotors) on surrounding flow field in terms of energy conversion processes. - The
actuationDiskSource
is applied on the volume cells (not on faces). This nuance might be important since theoretical actuator disks possess zero-thickness. - The
actuationDiskSource
inherits the traits of the fvOption, andcellSetOption
.
Corrections applied to:
U
- Velocity [m/s]
Required fields:
U
- Velocity [m/s]
Model equations🔗
The actuationDiskSource
possesses two options for force computations:
Froude
- Froude’s one-dimensional ideal actuator disk method
variableScaling
- Variable-scaling actuator disk method
Froude’s method🔗
The model expressions for Froude
method ([8], Eq. 3.9):
with
\[a = 1 - \frac{C_p}{C_T}\]Where:
- \(T\)
- Thrust magnitude [N]
- \(\rho_{\ref}\)
- Monitored incoming fluid density [kg/m\(^3\)]
- \(A\)
- Actuator disk planar surface area [m\(^2\)]
- \(\u_m\)
- Incoming velocity spatial-averaged on monitored region [m/s]
- \(\vec{n}\)
- Surface-normal vector of the actuator disk pointing upstream [-]
- \(a\)
- Axial induction factor [-]
- \(C_p\)
- Power coefficient [-]
- \(C_T\)
- Thrust coefficient [-]
Variable-scaling method🔗
The model expressions for variableScaling
method
(([31], Eqs. 5-6), ([30])):
with
\[C_T^* = C_T \left( \frac{ | \u_m | }{ | \u_o | } \right)^2\]Where:
- \(T\)
- Thrust magnitude [N]
- \(\rho_{\ref}\)
- Monitored incoming fluid density [kg/m\(^3\)]
- \(A\)
- Actuator disk planar surface area [m\(^2\)]
- \(\u_m\)
- Incoming velocity spatial-averaged on monitored region [m/s]
- \(\u_o\)
- Incoming velocity spatial-averaged on actuator disk [m/s]
- \(\vec{n}\)
- Surface-normal vector of the actuator disk pointing upstream [-]
- \(a\)
- Axial induction factor [-]
- \(C_p\)
- Power coefficient [-]
- \(C_T\)
- Thrust coefficient [-]
- \(C_T^*\)
- Calibrated thrust coefficient [-]
Operands🔗
Operand | Type | Location |
---|---|---|
input | - | - |
output file | dat | $POST=$FOAM_CASE/postProcessing/<FvO>/<time>/<file> |
Usage🔗
Example of the fvOptions specification using constant/fvOptions
file:
actuationDiskSource1
{
// Mandatory entries (unmodifiable)
type actuationDiskSource;
// Mandatory (inherited) entries (unmodifiable)
selectionMode <mode>; // e.g. cellSet as shown below
cellSet <cellSetName>;
// Mandatory entries (runtime modifiable)
diskArea 40.0;
diskDir (1 0 0);
Cp <Function1>;
Ct <Function1>;
// Conditional optional entries (unmodifiable)
monitorMethod <points|cellSet>;
monitorCoeffs
{
// Option-1
points
(
(p1x p1y p1z)
(p2x p2y p2z)
...
);
// Option-2
cellSet <monitorCellSet>;
}
// Optional entries (unmodifiable)
variant <forceMethod>;
// Optional entries (runtime modifiable)
sink true;
writeFileStart 0;
writeFileEnd 100;
// Optional (inherited) entries
...
}
where the entries mean:
Property | Description | Type | Required | Default |
---|---|---|---|---|
type | Type name: actuationDiskSource | word | yes | - |
diskArea | Actuator disk planar surface area | scalar | yes | - |
diskDir | Surface-normal vector of the actuator disk pointing upstream | vector | yes | - |
Cp | Power coefficient | Function1 | yes | - |
Ct | Thrust coefficient | Function1 | yes | - |
monitorMethod | Type of incoming velocity monitoring method - see below | word | no | points |
variant | Type of the force computation method - see below | word | no | Froude |
sink | Flag for body forces to act as a source (true ) or a sink (false ) |
bool | no | true |
writeFileStart | Start time for file output | scalar | no | 0 |
writeFileEnd | End time for file output | scalar | no | VGREAT |
The inherited entries are elaborated in:
Options for the monitorMethod
entry:
points | Monitor incoming velocity field at a given set of points
cellSet | Monitor incoming velocity field at a given cellSet
Options for the variant
entry:
Froude | Froude's one-dimensional ideal actuator disk method
variableScaling | Variable-scaling actuator disk method
Further information🔗
Tutorial:
Sample result
Source code:
History:
- Introduced in version 2.2.0