22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-3.4.1 (IL)

TRANSITION ON SWEPT WINGS

E. B. White, W. S. Saric
Arizona State University, USA

Keywords: stability, 3-d boundary layers, secondary instability

Crossflow-dominated swept-wing transition represents both a fundamentally challenging and a technologically important research problem. The nature of the crossflow instability is such that the boundary-layer flow is subject to strongly nonlinear behavior very early in its evolution. Because of this, it has resisted treatment by linear methods, including eN, and therefore, predicting the transition location for even the simplest configurations is not possible at present. This is in spite of the fact that a very complete understanding of the primary crossflow instability has been developed and exceptionally good agreement between experiments and computations has been obtained. What is lacking is a detailed description of the breakdown phenomenon in the final stages of transition. It is thought that breakdown is caused by the growth of a high-frequency secondary instability. Although there is growing evidence that this is the case, there is still little experimental data. It is the objective of the current work to provide such data on the behavior of the breakdown region. This data, coupled with the existing primary instability model, will be another step towards a complete transition prediction

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