Boundary Layer Theory: Part 2 Turbulent Flows

The flow laws of the actual flows at high Reynolds numbers differ considerably from those of the laminar flows treated in the preceding part. These actual flows show a special characteristic, denoted as turbulence. The character of a turbulent flow is most easily understood the case of the pipe flow. Consider the flow through a straight pipe of circular cross section and with a smooth wall. For laminar flow each fluid particle moves with uniform velocity along a rectilinear path. Because of viscosity, the velocity of the particles near the wall is smaller than that of the particles at the center. i% order to maintain the motion, a pressure decrease is required which, for laminar flow, is proportional to the first power of the mean flow velocity. Actually, however, one ob erves that, for larger Reynolds numbers, the pressure drop increases almost with the square of the velocity and is very much larger then that given by the Hagen Poiseuille law. One may conclude that the actual flow is very different from that of the Poiseuille flow.


Author: Nasa Technical Reports Server (Ntrs),Teil B. Grenzschichttheorie,Stroemungen Turbulente
Publisher: Bibliogov
Published: 07/31/2013
Pages: 142
Binding Type: Paperback
Weight: 0.59lbs
Size: 9.69h x 7.44w x 0.30d
ISBN: 9781287265894

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