Date of Award

7-1994

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Thomas Buter, PhD

Abstract

The use of tangential blowing to suppress the dynamic stall of a pitching airfoil is investigated numerically. The laminar two-dimensional, compressible Navier-Stokes equations are solved time-accurately using a Beam- Warming algorithm. A slot is located at four different positions along the surface of a NACA 0015 airfoil and air is injected in a nearly tangential sense along the upper surface. Suction control is also employed at one of these slot locations to directly compare with tangential-blowing control. Solution sensitivity to grid refinement, time-step size, numerical smoothing, and initial conditions is investigated at a Reynolds number of 2.4 x 10exp 4. Initial- condition and initial-airfoil-acceleration effects are analyzed for various pitch rates. Compressibility of M infinity 0.2 solutions is investigated. Numerical simulation uncertainties of jet-orientation angle and jet velocity profile are investigated. Studies are conducted to establish the effects of slot position, slot width, blowing-initiation angle, blowing velocity, pulsed blowing, and blowing at different pitch rates.

AFIT Designator

AFIT-DS-AA-94-4

DTIC Accession Number

ADA284887

Comments

The author's Vita page is omitted.

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