Smoking...One of the bad habits. I would say that you have to stop smoking If you have, as general. What about the flow after burning ? I have recognize that flow after burning through smoke has no turbulence. Isn't it ? You would support me I guess. Therefore, I, or course, have wondered about it that I have searched on it. There is a transition laminar to turbulence as the photography you have specified. Thanks to Reynolds Number, we could calculated ratio between inertia and viscous forces which is a sign of whether being turbulent or laminar flow. he descent of smoke can be see in the graphic as above. According to lecture note of Victor Zhurbas, the velocity of smoke at initial stage is about 30 cm/s and L is around 3 cm. Kinematic viscosity is taken as 0.14 cm^2/s.
Re= (30*3)/0.14 = 642 Result could be interpreted that Re goes through critical range in accordance with transition definition of laminar to turbulent. The phenomenon is two phase flow that has to be investigated within ambient conditions (velocity, temperature, pressure, etc.), The velocity should increase because the hot smoky region is less dense than the cooler air around it. As a result there's a net upward buoyant force on it, like on a helium balloon, causing an upward acceleration. So it should briefly speed up. Of course the hottest middle part of the plume speeds up the most. Toward the edges, the velocity gets closer to that of the surrounding air. This change of velocity from place to place, called shear, is what can drive turbulence. Whether the flow stays smooth (laminar) or turns turbulent depends on a quantity called the Reynolds number, which involves the shear, the size of the region, and the viscosity of the fluid. Here is a journal article related to mathematical model of cigar smoke. Besides, take a look on “Lewis Fry Richardson” (1881-1953), an English scientist. He interested in atmospheric turbulence and performed many terrestrial experiments. The Richardson number, a dimensionless parameter of the theory of turbulence is named for him. He famously summarized turbulence in rhyming verse in Weather Prediction by Numerical Process (it is also called as a poem as to turbulence): Big whirls have little whirls that feed on their velocity, and little whirls have lesser whirls and so on to viscosity. Have much fun.
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