Description🔗
The MachNo
function object computes the Mach number as a volScalarField
.
The Mach number is a dimensionless quantity representing the ratio of flow velocity past a boundary to the local speed of sound:
\[M = \frac{|\u|}{\sqrt{\gamma p/\rho}}\]where:
- \(M\)
- Mach number
- \(\u\)
- Velocity
- \(\gamma\)
- The ratio of specific heat of a gas at a constant pressure to heat at a constant volume
- \(p\)
- Static pressure
- \(\rho\)
- Fluid density
Operands🔗
Operand | Type | Location |
---|---|---|
input | volVectorField |
$FOAM_CASE/<time>/<inpField> |
output file | - | - |
output field | volScalarField |
$FOAM_CASE/<time>/<outField> |
Usage🔗
Example of the MachNo
function object
by using functions
sub-dictionary in system/controlDict
file:
MachNo1
{
// Mandatory entries (unmodifiable)
type MachNo;
libs (fieldFunctionObjects);
// Optional (inherited) entries
field <inpField>;
result <fieldResult>;
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: MachNo | word | yes | - |
libs | Library name: fieldFunctionObjects | word | yes | - |
The inherited entries are elaborated in:
Example by using the postProcess
utility:
postProcess -func MachNo
Further information🔗
Tutorial:
Source code:
API:
History:
- Introduced in version v1606+