Hi,

does someone know a link where I can find a picture of a smoking cigarette where I can see the transition from laminar to turbulent flow regime. I have to illustrate the difference between laminar and turbulent flow to non-technicians and I think that would be a nice example.

Thanks,

Tim

(1). A smoking cigarette is not a good idea. (even if you are working for a tobaco company) (2). Try a incense stick and take a few pictures using cheap one-time camera (film speed ISO800).

Check Van Dyke's book, An Album of Fluid Motion, Parabolic Press,Stanford, 1982 (Library of Congress catalog #81-83088).

The pictures you need are on p. 63, plates 107 and 108. They're reprinted from

Perry, A. E. & Lim, T. T. 1978, J. Fluid Mech., 88:451-463.

There is a good example of laminar and turbulent flow in the paper of

J.M. Hamilton and F.H. Abernathy, in J. Fluid Mech., 1994, vol.264, p.185.Figures 13, 14, 15 and 16.

This is a water table experiment with a (subcritical) transition to turbulence. Basically, the flow of water becomes unstable as it passes over an obstacle and turbulence develops only downstream from the object, the rest of the flow stays laminar. It is a nice picture, similar to the flow of water in a river bed with rocks. The photocopy of the pictures come out fine too.

PG

the simplest idea would be to buy some cigarettes and light them, one by one. The cheapest would be to get a cigarette from a frient. That's all.

best regards,

I.Dotsikas