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Boundary Layer Receptivity to Three-Dimensional Freestream Disturbances at Two-Dimensional RoughnessThe receptivity of a laminar boundary layer to an isolated three-dimensional convected disturbance is investigated in a low-speed wind tunnel experiment. The disturbance is created by the short-duration pulsed displacement of a small low-aspect-ratio wing located upstream of a flat plate. The height of the wing is set so that the convected disturbance grazes the edge of the flat-plate boundary layer. A receptivity site is provided by a two-dimensional roughness strip on the surface of the plate. The different propagation speeds of acoustic, convected and instability waves cause the various wave packets from the pulsed displacement to arrive at a downstream measurement station at different times, separating the phenomena and allowing them to be studied independently. Ensemble- averaged measurements are made with and without roughness on the plate. Preliminary analysis of the measurements suggest the presence of a two-dimensional T-S wave packet arising from an interaction between an acoustic wave and the roughness, and a three-dimensional T-S wave packet arising from an interaction between the localized convected disturbance and the roughness strip. The growth rates and spatial characteristics of the disturbances and the instability wave packets are measured as they propagate downstream.
Document ID
20020061289
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Dietz, Anthony
(NASA Ames Research Center Moffett Field, CA United States)
Sheehan, Daniel
(San Diego Univ. San Diego, CA United States)
Davis, Sanford
Date Acquired
August 20, 2013
Publication Date
January 1, 1997
Subject Category
Fluid Mechanics And Thermodynamics
Meeting Information
Meeting: DFD 1997 Meeting of the American Physical Society
Location: San Francisco, CA
Country: United States
Start Date: November 23, 1997
End Date: November 25, 1997
Sponsors: American Physical Society
Funding Number(s)
PROJECT: RTOP 522-31-12
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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