Numerical Study of Vortex Flow Control on High-Angle-of-Attack Slender Body

In general speaking, the missiles execute flight at high angles of attack in order to enhance their maneuverability. However, the inevitable side-force, which is caused by the asymmetric flow over these kinds of traditional slender body configurations with blunt nose at a high attack angle, induces the yawing or rolling deviation and the missiles will lose their predicted trajectory consequently. This study examines and diminishes the side-force induced by the inevitable asymmetric flow around this traditional slender body configuration with blunt nose at a high angle of attack (AoA = 50 deg). On one hand, the flow over a fixed blunt-nosed slender body model with strakes mounted at an axial position of x/D = 1.6–2.7 is investigated experimentally at α = 50 deg (D is the diameter of the model). On the other hand, the wingspan of the strakes is varied to investigate its effect on the leeward flow over the model. The Reynolds number is set at ReD = 1.54 × 105 based on D and incoming upstream velocity. The results verify that the formation of asymmetric vortices is hindered by the existence of strakes, and the strake-induced vortices develop symmetrically and contribute to the reduction in side-force of the model. In addition, the increase in strake wingspan reduces asymmetric characteristics of the vortex around the model and causes a significant decrease in side-force in each section measured. The strake with the 0.1D wingspan can reduce the sectional side-force to 25% of that in the condition without strakes.

Download Full-text

Numerical Simulations of Closed-Loop Flow Control of a Tangent Ogive at a High Angle of Attack

10.2514/6.2013-2923 ◽

2013 ◽

Author(s):

Christopher O. Porter ◽

Casey P. Fagley ◽

John A. Farnsworth ◽

Jurgen Seidel ◽

Thomas E. McLaughlin

Keyword(s):

Flow Control ◽

Numerical Simulations ◽

Closed Loop ◽

Angle Of Attack ◽

High Angle ◽

High Angle Of Attack

Download Full-text

FLOW CONTROL AND MECHANISM FOR SLENDER BODY AT HIGH ANGLE OF ATTACK

Modern Physics Letters B ◽

10.1142/s0217984905009936 ◽

2005 ◽

Vol 19 (28n29) ◽

pp. 1571-1574 ◽

Cited By ~ 3

Author(s):

XIAO MING ◽

YUNSONG GU

Keyword(s):

Flow Control ◽

High Frequency ◽

Angle Of Attack ◽

Control Technique ◽

High Angle ◽

Dynamic Measurements ◽

Wind Tunnel Experiments ◽

Rolling Angle ◽

High Angle Of Attack ◽

Side Force

The wind tunnel experiments for high angle of attack aerodynamics were designed from the inspiration of understanding the mechanism and development of an innovative flow control technique. The side force, varying with the different rolling angle, is featured by bi-stable situation, and can be easily switched by a tiny disturbance. A miniature strake is attached to the nose tip of the model. When the strake is stationary, the direction of the side force can be controlled. When the nose tip strake, as an unsteady control means, is swung the flow pattern could be controlled. The results obtained from dynamic measurements of section side force indicate that when the strake swing at lower frequency the side force can follow the cadence of the swinging strake. With increasing frequency, the magnitude of the side force decreases. At still high frequency, the side force diminishes to zero. The side forces could be also changed proportionally. Based on the experimental factors, the mechanism of the asymmetry is discussed.

Download Full-text