Mean Age of Air Convergence

msmith · December 12, 2013, 19:09

Hi all,

I've searched the forum and it seems this is a stupid problem to have, since no one else has it....

I've set up mean age of air in CFX using an additional variable and subdomain etc, however it isn't converging. The age essentially just increases as the iterations increase, even if the momentum residuals have converged...

Ideas?

msmith · December 16, 2013, 22:59

Ok so advice from support was that MAA equation needs quite a long time to converge because it relies on convecting all the flow from teh inlet through to the outlet. For flows with dead spots, this will take a long time to track the entire fluid path. This can be sped up by using a larger timestep or timescale factor (eg factor of 10).

December 12, 2013, 19:09	Mean Age of Air Convergence	#1
msmith New Member Michael Smith Join Date: Dec 2013 Location: Canberra, Australia Posts: 17 Rep Power: 12	Hi all, I've searched the forum and it seems this is a stupid problem to have, since no one else has it.... I've set up mean age of air in CFX using an additional variable and subdomain etc, however it isn't converging. The age essentially just increases as the iterations increase, even if the momentum residuals have converged... Ideas?

December 16, 2013, 22:59		#2
msmith New Member Michael Smith Join Date: Dec 2013 Location: Canberra, Australia Posts: 17 Rep Power: 12	Ok so advice from support was that MAA equation needs quite a long time to converge because it relies on convecting all the flow from teh inlet through to the outlet. For flows with dead spots, this will take a long time to track the entire fluid path. This can be sped up by using a larger timestep or timescale factor (eg factor of 10). A_Prakash likes this.

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