scholarly journals Side force control on slender body by self-excited oscillation flag

2016 ◽  
Vol 6 (5) ◽  
pp. 230-232 ◽  
Author(s):  
Jian Zhai ◽  
Weiwei Zhang ◽  
Chuanqiang Gao ◽  
Yanhua Zhang ◽  
Zhengyin Ye ◽  
...  
Keyword(s):  
Force Control ◽  
Slender Body ◽  
Side Force ◽  
Excited Oscillation

Strakes Effects on Asymmetric Flow Over a Blunt-Nosed Slender Body at a High Angle of Attack

2018 ◽  
Vol 141 (6) ◽  
Author(s):  
Qihang Yuan ◽  
Yankui Wang ◽  
Zhongyang Qi
Keyword(s):  
Angle Of Attack ◽  
Slender Body ◽  
Axial Position ◽  
High Angle ◽  
Asymmetric Flow ◽  
High Angle Of Attack ◽  
Side Force ◽  
Asymmetric Vortices ◽  
High Angles Of Attack ◽  
Blunt Nose

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.

Side Forces on a Ship’s Hull

1988 ◽  
Vol 32 (03) ◽  
pp. 203-207
Author(s):  
W. S. Hunter ◽  
P. N. Joubert
Keyword(s):  
Froude Number ◽  
Asymptotic Expansions ◽  
Experimental Results ◽  
Slender Body ◽  
Flat Plates ◽  
Slender Body Theory ◽  
Towing Tank ◽  
Side Force ◽  
Low Froude Number ◽  
Body Theory

Side forces on a ship traveling at small yaw angles are predicted using slender-body theory. The approach uses the method of matched asymptotic expansions, with a cascade of flat plates as a model for the submarine portion of the ship's hull. Resulting predictions of side force coefficients are then compared with experimentally measured values derived from towing tank tests of a typical (tanker) hull. Correlation between theoretical and experimental results was very good for yaw angles less than 8 deg at low Froude number (Fn = 0.134).

Direct Side Force Control for STOL Crosswind Landings

1974 ◽  
Vol 11 (10) ◽  
pp. 631-638 ◽  
Author(s):  
E. M. Boothe ◽  
H. J. Ledder
Keyword(s):  
Force Control ◽  
Side Force

Design and flight testing of digital direct side-force control laws

1985 ◽  
Vol 8 (2) ◽  
pp. 188-193 ◽  
Author(s):  
Scott L. Grunwald ◽  
Robert F. Stengel
Keyword(s):  
Force Control ◽  
Flight Testing ◽  
Control Laws ◽  
Side Force

EXPERIMENTAL INVESTIGATION OF SLENDERNESS EFFECT ON SIDE FORCE OF SLENDER BODY

2010 ◽  
Vol 24 (13) ◽  
pp. 1413-1416 ◽  
Author(s):  
TZONG-SHYNG LEU ◽  
JENG-REN CHANG ◽  
CHUN-LIN KUO
Keyword(s):  
Body Surface ◽  
The Body ◽  
Slender Body ◽  
Force Distribution ◽  
Wall Region ◽  
Side Force ◽  
Major Mechanism ◽  
Body Experiences ◽  
Formation And Evolution ◽  
Near Wall

This study investigates side force of a slender body with slenderness from 4.4 to 8.0. The experimental results show that flow over a slender body experiences a significant side force at angle-of-attack (AOA) higher than 30°. The side force reaches its maximum at AOA ≈ 50°. The present study demonstrates that slenderness (L/D) produces obvious influence on sectional side force distribution at high AOA. To understand the mechanism, evolution of near-wall vortex structure is investigated via hot wire and surface pressure measurements. It was found that one strong vortex is situated close to body surface and the other weak vortex away from the body, inducing a significant side force. Because the weak vortex lifts off early, a new vortex forms in near-wall region. Formation and evolution of the new vortex is the major mechanism that causes local sectional side force distribution exhibiting a wavy form with an alternating sign along the body. Therefore, overall side force does not necessarily increase with increasing slenderness. Reducing overall side force by canceling the alternating vortex-induced forces over the body surface is found if the slenderness L/D > 6.8 at AOA > 40°.

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