Influence of an Unfavourable Pressure Gradient on the Breakdown of Boundary Layer Streaks

Article type: Research Article

Authors: Chernoray, V. G. | Kozlov, V. V. | Lee, I. | Chun, H. H.

Affiliations: Applied Mechanics, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden | Institute of Theoretical and Applied Mechanics SB RAS, 630090, Novosibirsk, Russia. E-mail: kozlov@itam.nsc.ru | Naval Architecture & Ocean Engineering, Pusan National University, 609-735, Pusan, Korea

Abstract: Breakdown of boundary layer streaks is studied experimentally and compared at zero and adverse (positive) streamwise pressure gradients on a wing under fully controlled experimental conditions. The varicose mode of streak breakdown is found to be a dominant mode in the case of the adverse pressure gradient. A strong influence of pressure gradient upon the development of the streak and the secondary instability is revealed. The unfavourable pressure gradient is shown to alter the critical streak amplitude, the dispersion properties of the streak and the secondary disturbance, as well as attained maximum amplitudes for both the streak and the secondary disturbance.

Keywords: Visualization, hot-wire anemometry, wing flow, sinusoidal and varicose instabilities, streaks

Journal: Journal of Visualization, vol. 10, no. 2, pp. 217-225, 2007