Accession Number:

ADA210252

Title:

Basic Studies of the Unsteady Flow Past High Angle of Attack Airfoils

Descriptive Note:

Final rept. 1 Oct 1986-30 Oct 1988

Corporate Author:

FLORIDA STATE UNIV TALLAHASSEE DEPT OF MECHANICAL ENGINEERING

Personal Author(s):

• Krothapalli, Anjaneyulu
• Lourenco, Luiz
• Van Dommelen, Leon

Report Date:

1989-05-15

Pagination or Media Count:

130.0

Abstract:

An experimental and numerical simulations have been carried out to study the unsteady flow past an impulsively started NACA 0012 airfoil at different angles of attack Oalpha45 deg.. A novel experimental technique, commonly referred to as Particle Image Displacement Velocimetry PIDV, is successfully implemented to measure the instantaneous velocity fields. The velocity field is measured with sufficient accuracy so that the distribution of vorticity can be calculated. The unsteady separated flow fields generated by these airfoils contain large scale vortical structures such as a primary vortex generated at the leading edge of the airfoil with secondary vortices upstream of it a trailing vortex, and a vortex sheet type structure. The origins and time evolution of these structures are clearly depicted by the instantaneous velocity and vorticity fields. A random-walk vortex simulations of the full Navier-Stokes equations were performed as comparison. Keywords Unsteady flows High angle of attack airfoils Particle image velocimetry Vortex calculations.

Descriptors:

• *HIGH ANGLES
• *UNSTEADY FLOW
• *AIRFOILS
• *ANGLE OF ATTACK
• NUMERICAL ANALYSIS
• ACCURACY
• VORTICES
• TRAILING VORTICES
• TIME
• FLOW FIELDS
• PARTICLES
• IMAGES
• SHEETS
• EVOLUTION(GENERAL)
• LABORATORY PROCEDURES
• LEADING EDGES
• VELOCIMETERS
• NAVIER STOKES EQUATIONS
• FLOW SEPARATION
• DISPLACEMENT
• DISTRIBUTION
• SECONDARY FLOW
• VELOCITY
• COMPUTATIONS

Subject Categories:

• Aerodynamics
• Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE