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A. Kluwick, M. Kornfeld:
"On the effect of surface roughness in transonic high Reynolds number flow through slender channels";
accepted as talk for: 85th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM), Erlangen-Nürnberg; 2014-03-10 - 2014-03-14; in: "Proceedings in Applied Mathematics and Mechanics - PAMM", (2014), 2 pages.

In the present study transonic weakly three-dimensional flows at high Reynolds numbers in slender channels, as they are
found e.g. in micro nozzles and turbo-machines of micro-electromechanical- systems (MEMS), are considered. The channel
height is taken to be so small that the viscous layers forming at the channel walls start to interact strongly rather than weakly
with the predominantly inviscid core flow and, therefore, the classical boundary layer approach fails. The resulting viscousinviscid
interaction problem is formulated using matched asymptotic expansions and found to be governed by a triple deck
structure. As a consequence, the properties of the inviscid core region and the viscous wall layers have to be calculated simultaneously
in the interaction region. Weakly three-dimensional effects caused by surface roughness, upstream propagating
flow perturbations and boundary layer separation are discussed.