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QF-Error-Tracking / QFVD5

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"Number of Ignitions" not working as expected #21

Closed zacharycope0 closed 1 year ago

zacharycope0 commented 1 year ago

Describe the bug While running tests for Issue #20, I noticed the following:

For a 60s simulation with a 1000m ignition line, when I set the Number of Ignitions to 2 the head fire develops much faster than when I set the number to 100. The behavior may result from me placing my initial ignition at the edge of the domain. Another thought was that the strong plume from the initial 100 ignitions caused entrainment that prevented the head fire from spreading as quickly.

Do you think this difference in fire behavior is the result of a bug or based on how my run is set up?

Desktop (please complete the following information):

Screenshots

Number of Ignitions = 2 image image

Number of Ignitions = 100 image image

zacharycope0 commented 1 year ago

I will rerun and print winds to see its may be plume/entrainment related.

drobinson6045 commented 1 year ago

Your intuition on entrainment is right. I demonstrated this when the ignition change was initially pushed. As the ignition count gets larger a greater amount of fuel is combusted initially. This creates stronger plumes leading to stronger indrafts. The effect is more obvious in cases like this where a large fireline is ignited instantaneously.

zacharycope0 commented 1 year ago

@drobinson6045. Thanks for the reply. I'll show the group on Wednesday to remind others to be aware of this dynamic.