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On Roughness — Induced Transition: Facts, Views, and Speculations

  • Mark V. Morkovin
Part of the ICASE/NASA LaRC Series book series (ICASE/NASA)

Abstract

The mechanisms whereby small distributed roughness promote transition to turbulence are unknown and represent bypasses to known instability scenarios, including the e N design method. Mechanisms associated with single-roughness elements are partially understood (at least at low speeds) but probably not quantifiable. Yet, when favorable-pressure gradient laminar-flow airfoils were designed, roughness was the primary agent which rendered them nonlaminar in practice. Nearly blind correlation from a limited bases of experimental data still governs roughness sensitive designs. The topic was put on the agenda of the workshop first because of its obvious practical importance. Secondly, it is hoped that our vastly improved instrumentation and computer capabilities in the 1990’s may lead to research into the mechanisms themselves and thereby establish a more rational basis for design correlations.

Keywords

Roughness Element Laminar Boundary Layer Streamwise Vortex Horseshoe Vortex Hairpin Vortex 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag New York Inc. 1990

Authors and Affiliations

  • Mark V. Morkovin
    • 1
  1. 1.Illinois Institute of TechnologyChicagoUSA

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