Aerodynamic Step-Induced Vortex
Aerodynamic Performance of an Airfoil with
Step-Induced Vortex for Lift Augmentation
J. Aerosp. Engrg. Volume 11, Issue 1, pp. 9-16 (January 1998)
Issue Date: January 1998
Fathi Finaish
Assoc. Prof. of Aerosp. Engrg., Dept. of Mech. and Aerosp. Engrg. and Engrg. Mech., Univ. of Missouri, Rolla, MO 65401.
Stephen Witherspoon
Sr. Engr., McDonnell Douglas Corp., St. Louis, MO 63166; formerly, Grad. Res. Asst., Dept. of Mech. and Aerosp. Engrg. and Engrg. Mech., Rolla, MO.
Physical and numerical experiments on flow developments around an NACA-0012 airfoil were conducted to explore the possibility of enhancing the airfoil’s aerodynamic performance by vortex lift augmentation. The paper focuses on the effects of the separated flow and subsequent vortex formation, generated by backward-facing steps on pressure distributions and corresponding flow occurrences around the airfoil. Various step configurations are examined to determine their effect on lift and on lift-to-drag ratios. A discussion of the effects of main geometrical parameters of upper and lower surface steps on the airfoil performance, based on computational and physical flow visualization experiments, are presented. The results suggest that incorporation of backward-facing steps on the lower surface that are located at the midchord and extend back to the trailing edge with 50 depth of the airfoil chord may lead to considerable enhancements in lift coefficients and lift-to-drag ratios. The data produced may serve as a reference for future studies on the possible use of separated vortex structures in enhancing the aerodynamic or hydrodynamic performance of vehicles and structures.
©1998 American Society of Civil Engineers
(source)
Aerodynamic Characteristics of Airfoils With
Backward-Facing Step Configurations
Document Number: 961297
Date Published: May 1996
Author(s):
Stephen Witherspoon - University of Missouri
Fathi Finaish - University of Missouri
Abstract:
A computational study of flow developments over airfoils with backward-facing steps is conducted to explore the possibility of enhancing aerodynamic performance of the airfoils by vortex generation. The study focuses on the effects of the separated flow and subsequent vortex formation generated by the step on pressure distributions around two airfoil profiles. Step location and size are varied to determine their effect on lift, drag, and L/D ratio. A discussion of the effects and trends of the various step configurations on airfoil performance is presented along with the results that may serve as a reference for employing a control criteria to optimize airfoil geometries during flight.
(Source)
