[hemph]

Description:
The application gives erroneous solution for the Ua-field when the particle-particle force is included (g0 > 0). If settling particles are simulated, the velocity of the particles does not approach zero as they reach the bottom of the domain.

Solution. The ppMagf-term in alphaEqn.H: should be divided by alphaf on row 26.

Old:
ppMagf = g0*rUaAf*min(exp(preAlphaExp*(alphaf - alphaMax)), expMax);

New:
ppMagf = 1.0/(rhoa*max(alphaf,SMALL))*g0*rUaAf*min(exp(preAlpha Exp*(alphaf - alphaMax)), expMax);

Also row 32 in alphaEqn.H needs to be changed.

Old:
alphaEqn -= fvm::laplacian(ppMagf, alpha);

New:
alphaEqn -= fvm::laplacian(alphaf*ppMagf, alpha);

Solver/Application:
twoPhaseEulerFoam

Source file:
alphaEqn.H

Testcase:
twoPhaseEulerFoamPack1D.tar.gz

Platform:
All

Version:
All

Notes:
The dimension of g0 is in Pascal in most references. In twoPhaseEulerFoam the dimensions of g0 is Pa/(kg/m3). To aid comparison between models, the ppMagf term should be divided by rho, as
ppMagf = 1.0/(rhoa*max(alphaf,SMALL))*g0*rUaAf*min(exp(preAlpha Exp*(alphaf - alphaMax)), expMax);

with a corresonding change to the dimensions of g0 in constant/ppProperties