The regionSizeDistribution
function object creates a droplet size distribution via interrogating a continuous phase fraction field.
Looks up a phase-fraction (alpha) field and splits the mesh into regions based on where the field is below the threshold value. These regions ("droplets") can now be analysed.
Regions:
volScalarField
Output (volume scalar) fields include:
Histogram:
minDiameter
, maxDiameter
, nBins
)volVectorField
s these are those of the 3 components and the magnitude.origin
, direction
and maxDiameter
up to maxDownstream
Operand | Type | Location |
---|---|---|
input | - | - |
output file | - | $FOAM_CASE/postProcessing/<FO>/<time>/<files> |
output field | - | - |
Example of the regionSizeDistribution
function object by using functions
sub-dictionary in system/controlDict
file:
regionSizeDistribution1 { // Mandatory entries (unmodifiable) type regionSizeDistribution; libs (fieldFunctionObjects); // Mandatory entries (runtime modifiable) field alpha; patches (inlet); fields (p U); threshold 0.4; maxDiameter 5e-5; nBins 100; setFormat gnuplot; // Optional entries (runtime modifiable) minDiameter 0.0; coordinateSystem { origin (0 0 0); rotation { type axes; e3 (0 0 1); e1 (1 0 0); } } // Optional downstream iso-plane bins isoPlanes true; // Mandatory entries if isoPlanes=true (runtime modifiable) // Plane normal and point definition origin (1e-4 0 5e-4); direction (1 0 1); // Maximum diameter of the cylinder formed by the origin point // and direction maxD 3e-4; // Maximum downstream distance maxDownstream 6e-4; // Number of iso-plane bins nDownstreamBins 20; // Optional (inherited) entries writePrecision 8; writeToFile true; useUserTime true; region region0; enabled true; log true; timeStart 0; timeEnd 1000; executeControl timeStep; executeInterval 1; writeControl timeStep; writeInterval 1; }
where the entries mean:
Property | Description | Type | Required | Default |
---|---|---|---|---|
type | Type name: regionSizeDistribution | word | yes | - |
libs | Library name: fieldFunctionObjects | word | yes | - |
field | Phase field to interrogate | word | yes | - |
patches | Patches wherefrom the liquid core is identified | wordList | yes | - |
fields | Fields to sample | wordList | yes | - |
threshold | Phase fraction applied to delimit regions | scalar | yes | - |
maxDiameter | Maximum droplet diameter | scalar | yes | - |
minDiameter | Minimum droplet diameter | scalar | no | 0.0 |
nBins | Number of bins for histogram | label | yes | - |
setFormat | Output format | word | yes | - |
isoPlanes | Flag for isoPlanes | bool | no | false |
origin | Origin of the plane when isoPlanes is used | vector | yes | - |
direction | Direction of the plane when isoPlanes is used | vector | yes | - |
maxD | Maximum diameter of the sampling cylinder when isoPlanes is used | vector | yes | - |
nDownstreamBins | Number of bins when isoPlanes is used | label | yes | - |
maxDownstream | Maximum distance from origin when isoPlanes is used | scalar | yes | - |
The inherited entries are elaborated in:
Usage by the postProcess
utility is not available.
Tutorial:
Source code:
History