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Wind tunnel measurements of sphere drag at supersonic speeds and low Reynolds numbers

Published online by Cambridge University Press:  28 March 2006

Peter P. Wegener
Affiliation:
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California Now at Yale University, New Haven, Connecticut.
Harry Ashkenas
Affiliation:
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California

Abstract

Sphere drag has been measured in a low-density supersonic wind tunnel by a simple displacement technique. A conical nozzle of fixed geometry, operated at a constant supply temperature of about 300 °K was used. Test section Mach numbers ranged between 3.8 and 4.3 depending on supply pressure. The Reynolds number and Knudsen number range, based on free-stream conditions and sphere diameter, were 50 < Re < 1000 and 0·106 < Kn < 0·006, respectively. This range was achieved by varying sphere size and supply pressure. The drag coefficient was found to increase from a value of CD = 1·17 at Re = 1000 to CD = 1·73 at Re = 50.

Type
Research Article
Copyright
© 1961 Cambridge University Press

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