Journal of Fluid Mechanics

Active control of laminar-turbulent transition

H. W.  Liepmann a1 and D. M.  Nosenchuck a1
a1 California Institute of Technology, Pasadena, CA 91109, U.S.A.

Article author query
liepmann hw   [Google Scholar] 
nosenchuck dm   [Google Scholar] 


Instability waves, commonly called T-S waves, can be introduced in a laminar boundary layer by periodic heating of flush-mounted heating elements. Experiments have demonstrated that nearly complete cancellation of a T-S wave excited in this way can be achieved by using a second downstream heating element with a suitable phase shift. As one application of the technique, a single element together with a feedback loop activated by measured wall shear stress has been used to reduce the amplitude of naturally occurring laminar instability waves. A significant increase in the transition Reynolds number has been achieved.

(Published Online April 20 2006)
(Received November 21 1981)