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Control of laminar-instability waves using a new technique

Published online by Cambridge University Press:  20 April 2006

H. W. Liepmann
Affiliation:
Graduate Aeronautical Laboratories, California Institute of Technology, Pasadena, CA 91125, U.S.A.
G. L. Brown
Affiliation:
Graduate Aeronautical Laboratories, California Institute of Technology, Pasadena, CA 91125, U.S.A. Present address: Aeronautics Research Laboratory (A.R.L.), Melbourne, Australia.
D. M. Nosenchuck
Affiliation:
Graduate Aeronautical Laboratories, California Institute of Technology, Pasadena, CA 91125, U.S.A.

Abstract

A new technique using surface-film activators has been developed to induce and control laminar-instability waves by periodic heating. A flat plate was instrumented and installed in the GALCIT High-Speed Water Tunnel with flush-mounted surface heaters and probes. Extremely two-dimensional naturally occurring Tolmien-Schlichting (TS) waves were observed along with the subsequent formation of turbulent spots. Laminar-instability waves were then excited in a controlled fashion using the surface-mounted heaters. A preliminary experiment on cancellation of excited laminar-instability waves was carried out. Finally, turbulent spots were produced using amplitude-modulated bursts to form Gaussian TS wave packets. Flow visualization, along with wall shear measurements, was used to infer the velocity and vorticity field near the wall.

Type
Research Article
Copyright
© 1982 Cambridge University Press

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