Difference between revisions of "ChtMultiRegionFoam"
From OpenFOAMWiki
(→Momentum conservation) |
(→Momentum conservation) |
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| Line 54: | Line 54: | ||
\frac{ \partial (\rho {u}_i)}{\partial t} + \frac{\partial}{\partial x_j} \left( \rho {u}_j u_i \right) = | \frac{ \partial (\rho {u}_i)}{\partial t} + \frac{\partial}{\partial x_j} \left( \rho {u}_j u_i \right) = | ||
| − | - \frac{\partial p_{rgh}} {\partial{x_i}} | + | - \frac{\partial p_{rgh}} {\partial{x_i}} - \frac{\partial \rho g_j x_j}{\partial x_i} + \frac{\partial}{\partial x_j} \left( \tau_{ij} + \tau_{t_{ij}} \right) |
</math></center> | </math></center> | ||
| Line 61: | Line 61: | ||
<math> u </math> represent the velocity, <math> g_i </math> the gravitational acceleration, <math> p_{rgh} = p - \rho g_j x_j </math> the pressure minus the hydrostatic pressure and | <math> u </math> represent the velocity, <math> g_i </math> the gravitational acceleration, <math> p_{rgh} = p - \rho g_j x_j </math> the pressure minus the hydrostatic pressure and | ||
<math> \tau_{ij} </math> and <math> \tau_{t_{ij}} </math> are the viscose and turbulent stresses. | <math> \tau_{ij} </math> and <math> \tau_{t_{ij}} </math> are the viscose and turbulent stresses. | ||
| + | |||
| + | The source code can be found in Ueqn.H: | ||
| + | |||
| + | <br><cpp> | ||
| + | |||
| + | // Solve the Momentum equation | ||
| + | |||
| + | MRF.correctBoundaryVelocity(U); | ||
| + | |||
| + | tmp<fvVectorMatrix> tUEqn | ||
| + | ( | ||
| + | fvm::ddt(rho, U) + fvm::div(phi, U) | ||
| + | + MRF.DDt(rho, U) | ||
| + | + turbulence.divDevRhoReff(U) | ||
| + | == | ||
| + | fvOptions(rho, U) | ||
| + | ); | ||
| + | fvVectorMatrix& UEqn = tUEqn.ref(); | ||
| + | |||
| + | UEqn.relax(); | ||
| + | |||
| + | fvOptions.constrain(UEqn); | ||
| + | |||
| + | if (pimple.momentumPredictor()) | ||
| + | { | ||
| + | solve | ||
| + | ( | ||
| + | UEqn | ||
| + | == | ||
| + | fvc::reconstruct | ||
| + | ( | ||
| + | ( | ||
| + | - ghf*fvc::snGrad(rho) | ||
| + | - fvc::snGrad(p_rgh) | ||
| + | )*mesh.magSf() | ||
| + | ) | ||
| + | ); | ||
| + | |||
| + | fvOptions.correct(U); | ||
| + | K = 0.5*magSqr(U); | ||
| + | } | ||
| + | |||
| + | fvOptions.correct(U); | ||
| + | |||
| + | |||
| + | </cpp><br> | ||
====Energy conservation==== | ====Energy conservation==== | ||
Revision as of 18:15, 2 November 2018
ChtMultiRegionFoam
Solver for steady or transient fluid flow and solid heat conduction, with conjugate heat transfer between regions, buoyancy effects, turbulence, reactions and radiation modelling.
Contents
1 Equations
For each region defined as fluid, the according equation for the fluid is solved and the same is done for each solid region. The regions are coupled by a thermal boundary condition.
1.1 Equations Fluid
For each fluid region the compressible Navier Stokes equation are solved.
1.1.1 Mass conservation
The variable-density continuity equation is
 | (1) |
The source code can be found in src/finiteVolume/cfdTools/compressible/rhoEqn.H:
{ fvScalarMatrix rhoEqn ( fvm::ddt(rho) + fvc::div(phi) == fvOptions(rho) ); fvOptions.constrain(rhoEqn); rhoEqn.solve(); fvOptions.correct(rho); }
1.1.2 Momentum conservation
 | (2) |
represent the velocity, 
the gravitational acceleration, 
the pressure minus the hydrostatic pressure and
and 
are the viscose and turbulent stresses.
The source code can be found in Ueqn.H:
// Solve the Momentum equation
MRF.correctBoundaryVelocity(U);
tmp<fvVectorMatrix> tUEqn
(
fvm::ddt(rho, U) + fvm::div(phi, U)
+ MRF.DDt(rho, U)
+ turbulence.divDevRhoReff(U)
==
fvOptions(rho, U)
);
fvVectorMatrix& UEqn = tUEqn.ref();
UEqn.relax();
fvOptions.constrain(UEqn);
if (pimple.momentumPredictor())
{
solve
(
UEqn
==
fvc::reconstruct
(
(
- ghf*fvc::snGrad(rho)
- fvc::snGrad(p_rgh)
)*mesh.magSf()
)
);
fvOptions.correct(U);
K = 0.5*magSqr(U);
}
fvOptions.correct(U);
