Flow Behavior in Side-View Plane of Pitching Delta Wing

Mehmet Can Pektas,Huseyin Akilli,Besir Sahin,Ilyas Karasu,Mehmet Oguz Tasci,P Dančová

doi:10.1051/epjconf/201818002080

Abstract

In the present investigation, a delta wing which has 70° sweep angle, Λ was oscillated on its midcord according to the equation of α(t)=αm+α0sin(ωet). This study focused on understanding the effect of pitching and characterizing the interaction of vortex breakdown with oscillating leading edges under different yaw angles, β over a slender delta wing. The value of mean angle of attack, αm was taken as 25°. The yaw angle, β was varied with an interval of 4° over the range of 0°≤β≤ 16°. The delta wing was sinusoidally pitched within the range of period of time 5s≤Te≤60s and reduced frequency was set as K=0.16, 0.25, 0.49, 1.96 and lastly amplitude of pitching motion was arranged as α0=±5°.Formations and locations of vortex breakdown were investigated by using the dye visualization technique in side view plane.

Highlights

As a result of past researches, delta wings are main element of combat aircrafts
[6] demonstrated that structures of vortex bursting and vortical flow over a non-slender diamond wing are sensitively effected by yaw angle, β using dye visualization and the PIV technique and time averaged flow data over the wing surface changes profoundly increasing over the yaw angle, β=6°
Β is increased to the value of 20°, well-defined Kelvin-Helmholtz (K-H) instabilities appear on both sides of leading edge vortex before and after onset of vortex breakdown clearly. [8] defined flow separation and integration on the surface of wing via numerical methods for the delta wings having sweep angles, Λ of 65° and 76°/40°

Summary

Introduction

As a result of past researches, delta wings are main element of combat aircrafts. The control of vortex dynamics, unsteady flow characteristic and physics are considerably important to improve the maneuverability of air vehicles [1]. [5] examined flow characteristics over the lambda wing under variation of angle of attack within the range of 7°≤α≤17° using dye visualization and the stereo PIV technique. They proved that flow structure and development of vortex breakdown profoundly are affected by angle of attack, α. [6] demonstrated that structures of vortex bursting and vortical flow over a non-slender diamond wing are sensitively effected by yaw angle, β using dye visualization and the PIV technique and time averaged flow data over the wing surface changes profoundly increasing over the yaw angle, β=6°. Β is increased to the value of 20°, well-defined Kelvin-Helmholtz (K-H) instabilities appear on both sides of leading edge vortex before and after onset of vortex breakdown clearly. [8] defined flow separation and integration on the surface of wing via numerical methods for the delta wings having sweep angles, Λ of 65° and 76°/40°

Methods

Discussion

Conclusion