Accession Number:

ADA137070

Title:

Some Unsteady Aerodynamic Characteristics of Separated and Attached Flow

Descriptive Note:

Annual rept. 1 Sep 1982-31 Sep 1983

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF AERONAUTICS AND ASTRONAUTICS

Report Date:

1983-08-31

Pagination or Media Count:

59.0

Abstract:

Aerodynamic characteristics of separated and attached unsteady flow about a NACA 0012 airfoil have been measured for reduced frequency from 0 to 6.4 and angles of attack up to 18 deg. Results from boundary layer and near wake ensemble averaged velocity, Reynolds stress and surface pressure distributions are presented. The flow was determined to be locally two-dimensional away from the separation point if present, within or - 14 span of the airfoil centerline. A convected component of the unsteady separated pressure field was identified, and the dependence on reduced frequency, angle of attack, Reynolds number and form of transition is discussed. A geometric similarity model is suggested to explain the presence of a periodic component measured for the ensemble averaged Reynolds stresses. Finally, studies of the relative importance of acoustic and upwash velocity components of the excitation are summarized.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE