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.actuationDiskSource
is applied on the volume cells (not on faces). This nuance might be important since theoretical actuator disks possess zero-thickness.actuationDiskSource
inherits the traits of the fvOption, and cellSetOption
.Corrections applied to:
U | Velocity [m/s]
Required fields:
U | Velocity [m/s]
The actuationDiskSource
possesses two options for force computations:
Froude | Froude's one-dimensional ideal actuator disk method variableScaling | Variable-scaling actuator disk method
The model expressions for Froude
method ([8], Eq. 3.9):
\[ T = 2 \rho_{ref} A | \u_m \cdot \vec{n} |^2 a (1-a) \]
with
\[ a = 1 - \frac{C_p}{C_T} \]
where
\( T \) | = | Thrust magnitude [N] |
\( \rho_{ref} \) | = | Monitored incoming fluid density [kg/m3] |
\( A \) | = | Actuator disk planar surface area [m2] |
\( \u_m \) | = | 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 [-] |
The model expressions for variableScaling
method (([86], Eqs. 5-6), ([87])):
\[ T = 0.5 \rho_{ref} A | \u_o \cdot \vec{n} |^2 C_T^* \]
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/m3] |
\( A \) | = | Actuator disk planar surface area [m2] |
\( \u_m \) | = | 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 [-] |
Operand | Type | Location |
---|---|---|
input | - | - |
output file | dat | $POST=$FOAM_CASE/postProcessing/<FvO>/<time>/<file> |
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
Tutorial:
Sample result
Source code:
History