This source deflects the flow direction by imposing a variable pressure drop. This is particularly useful for cases that include louvres, e.g. HVAC registers, whereby to resolve the louvres using the mesh can lead to excessive cell counts and excessively restrict the calculation time step.
Properties🔗
The pressure drop across the cellZone
is evaluated according to the
options:
-
constant
: user-specified \(\Delta p\) [Pa] -
volumetricFlowRateTable
: \(\Delta p\) is read as a table from file -
DarcyForchheimer
: \(\Delta p = (D + 0.5 \rho |U| I ) |U| L\) [Pa] where D, I and L are user inputs. - the
cellZone
should describe a set of cells with a 1-cell thickness in the flow direction - the source requires the set of faces upstream of the
cellZone
to be specified as afaceZone
A sample result is shown below, where the effect of flow deflection across the cellZone is clearly evident.
Usage🔗
The option is specified using:
registerOrientation
{
type directionalPressureGradientExplicitSource;
active true;
selectionMode cellZone;
cellZone c1Zone;
fieldNames (U);
flowDir (1 2 0); // new flow direction in the general coordinate system
relaxationFactor 0.3; // relax the application of the source term
faceZone f1Zone; // faceZone upstream the cellZone
// Pressure drop model \[Pa\]
model DarcyForchheimer; // volumetricFlowRateTable | constant
// DarcyForchheimer
// deltaP = (D*mu + 0.5*rho*magUn)*magUn*length
D 5e7;
I 0;
length 0.01; // Virtual thickness of the porosity corresponding to the D and I values
// constant pressure drop model
// pressureDrop 8;
// volumetricFlowRateTable pressure drop model
// outOfBounds clamp;
// file "volFlowRateTable";
}
Further information🔗
Tutorials
Source code