Question

what is buoyancy of smoke at the molecular level, and is the smoke laminar or turbulent at the very tip of flames rolling from a window?

Answer 1

Smoke consist of basicly Carbon mono oxide (CO) molecule or unburn Carbon. because of the lighter weight of CO (28) than air (29) smoke try to move upward in air.

bouancy is basically pressure diffrence between upper region and lower region. so smoke in air move in upward direction.

b) flame rolling from window in this smoke is in turbulent flow . because there will be not orderly flow from window, smoke try to move from zig zag path. so it is turbulent flow