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Old   November 7, 2003, 01:24
Default baffle in use
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guang ai
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I have a problem with using baffle. I run a problem with a baffle put in nearly half of the path. It was keeping diverged in less than 200 iteration no matter what a relaxation I selected, such as R for press < 0.05. Once I switch the fluid adjecent to baffle to solid, calculation converged to -3 order of magnitude in mass. Does anyone have similar problem before or any suggestion, I will feel very grateful.
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Old   November 7, 2003, 14:27
Default Re: baffle in use
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Marc
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Is your flow domain completely separated by the baffles? That would imply that they are permeable baffles. In that case: Start with a low pressure loss over the baffles and restart with higher ones, until you reach your desired value.
Hope that helps, Marc
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Old   November 9, 2003, 20:14
Default Re: baffle in use
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guang ai
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thank you for your response. my case is not that complicated as you guessed, with only mesh seems complex. it is a problem with flow bifurcated for a distance and merged again at downstream. once a baffle works as a door shut off one side path, diverge happens. mesh quality is not good but works well as i mentioned in first post.
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Old   November 10, 2003, 05:51
Default Re: baffle in use
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Brian
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If your baffle door shuts off a side path, and the fluid in that path becomes completely separated from the rest of the flow, it becomes a two-stream problem. In other words, you have two completely separate flow domains. This is numerically unstable, and requires some special treatment.

See Tutorial 13 for how to handle that - Tut 13 is a moving mesh case, but you should get the idea.
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