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|ID||Project||Category||View Status||Date Submitted||Last Update|
|0001209||OpenFOAM||[All Projects] Bug||public||2014-03-06 22:54||2015-04-30 20:19|
|Fixed in Version|
|Summary||0001209: Should MULES use alphaMax rather than 1 with particulate models?|
|Description||The MULES call in twoPhaseEulerFOAM / twoPhaseSystem.C is|
However in the previous implementation of twoPhaseEulerFoam, the bounds for alpha were set to 0 and alphaMax in the case of particulate flows, where alphaMax < 1. Shouldn't this be the case also in the new twoPhaseEulerFoam?
|Tags||No tags attached.|
||I thought about it and concluded that it wasn't clear that alphaMax is a preferable because it is a soft limit; the phase-fraction may exceed alphaMax without serious problem. If alphaMax is used for the MULES limiter upwind differencing would be used anywhere alpha exceeds alphaMax; do you think that would be a good thing?|
I see your point. Indeed some models (Schaeffer, for example) let alphaMax be a soft limit, while others consider it as a hard limit (kinetic theory, Johnson and Jackson), so it's not clear.
I asked because with models that consider it a hard limit, alpha is limited when it approaches alphaMax, to avoid divergence of the particle pressure. This in some cases leads to a phase pressure that isn't sufficient to prevent a further increase in alpha, which can become very high. If I understand it correctly, MULES should enforce alphaMax as a hard limit, and prevent this.
> If I understand it correctly, MULES should enforce alphaMax as a hard limit,
> and prevent this
Yes, provided the schemes (other than convection) are bounded schemes. For example if the laplacian is corrected on a non-orthogonal mesh MULES cannot currently guarantee boundedness as it operates only on the convection flux.
Nevertheless I take your point and will change the MULES call to limit to alphaMax.
||Resolved by commit 97056cd4664657296e7028756edc05cdb87b0e06|
|2014-03-06 22:54||albertop||New Issue|
|2014-03-06 23:14||henry||Note Added: 0002931|
|2014-03-07 03:10||albertop||Note Added: 0002932|
|2014-03-07 08:43||henry||Note Added: 0002935|
|2014-03-07 23:40||henry||Note Added: 0002938|
|2014-03-07 23:40||henry||Status||new => resolved|
|2014-03-07 23:40||henry||Resolution||open => fixed|
|2014-03-07 23:40||henry||Assigned To||=> henry|