Publication:
Schlieren Studies of Compressibility Effects on Dynamic Stall of Airfoils in Transient Pitching Motion

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Authors
Chandrasekhara, M.S.
Ahmed, S.
Carr, L.W.
Subjects
Advisors
Date of Issue
1990-08
Date
August 20-22, 1990
Publisher
Language
Abstract
Compressibility effects on the flowfield of an airfoil executing rapid transient pitching motion from 0 - 60 degrees over a wide range of Mach numbers and pitching rates were studied using a stroboscopic schlieren flow visualization technique. The studies have led to the first direct experiments] documentation of multiple shocks on the airfoil upper surface flow for certain conditions. Also, at low Mach numbers, additional coherent vortical structures were found to be present along with the dynamic stall vortex, whereas at higher Mach numbers, the flow was dominated by a single vortex. The delineating Mach number for significant compressibility effects was 0.3 and the dynamic stall process was accelerated by increasing the Mach number above that value. Increasing the pitch rate monotonically delayed stall to angles of attack as large as 27 degrees.
Type
Conference Paper
Description
Series/Report No
Department
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Funder
AFOSR-MIPR-87-0029 and 88-0010
NAVAIR
ARO
Format
16 p.
Citation
8th Applied Aerodynamics Conference August 20-22, 1990/Portland,Oregon
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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