AN EXPERIMENTAL INVESTIGATION OF THE STABILITY OF POISEUILLE FLOW.
NAVAL POSTGRADUATE SCHOOL MONTEREY CALIF
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A theoretical and experimental investigation of the stability of developing laminar flow in a circular pipe subjected to small, rotationally symmetric torsional disturbances is presented. Analytically, developing mean velocity profiles were represented in polynomial series form and subsequent formulations yielded determinations on stability which reduce to the classical conclusions for the case of fully developed flow. Experimentally, torsional disturbances were imposed upon a developing laminar pipe flow by sinusoidally rotating a 1.5 inch 1 diameter length of pipe in the entrance region of a carefully constructed wind tunnel facility. For flows with maximum Reynolds numbers of 8500, maximum amplitude and frequency of oscillation were 12 inch and 30 Hz., respectively. Hot wire anemometer measurements verified the stability of the developing flow field. Moreover, measured wave speeds and decay factors compare favorably to calculated values. Author
- Fluid Mechanics