Aerodynamic Characteristics Of Delta Wing Research Articles

Corrugation Assisted Enhancement of Aerodynamic Characteristics of Delta Wing for Micro Aerial Vehicle

Some of the existing challenges of fixed-wing micro aerial vehicle designs at low Reynolds number are low lift and reduced aerodynamic efficiency. Delta wings, despite their characteristic maneuverability, are rarely used for micro aerial vehicles, perhaps due to the limited lifting capacity because of the reduced aspect ratio. Corrugations on insect wings are ubiquitous and augment the aerodynamic performance in a similar Reynolds number regime. Herein, corrugations are applied to enhance the lift and aerodynamic efficiency of a delta wing. Three delta-wing geometries are examined using numerical simulations at a Reynolds number of : a nonslender delta wing with 53 deg leading-edge sweep and two variants with corrugations in the rear planform. The simulations reveal that the variants potentially offer approximately 11 and 27% increments in the aerodynamic efficiency and the lift, respectively, over the conventional delta wing at an angle of attack of 5 deg. Moreover, the corrugations strengthen the leading-edge vortices and generate an additional nosedown moment about the leading edge. The introduction of corrugations on micro aerial vehicle wings could be a passive technique to potentially improve the aerodynamic characteristics, without any significant weight or drag penalty.

Effect of Shapes and Turbulent Inlet Flow to Vortices on Delta Wings

This paper aims to estimate the effect of turbulent inlet flow to vortices on Delta wing with four different turbulence intensity from 0.5% to 15% and the effect of taper ratios to aerodynamic characteristics of Delta wings with four taper ratios: 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7. The main purpose of this paper is to find out the formation, development, and breakdown of vortices on Delta wings when changing taper ratios and turbulence intensity thence determining the center of vortices with the range of attack angles from 5o to 40o in low velocities about 2.5 m/s. This research uses Delta wing models with a 40o swept-back leading edge, the root chord length 150 mm, and a thickness 5 mm. The problem is simulated by using ANSYS fluent and experiment in the subsonic wind tunnel to compare and validate results. The Delta wing models are meshed by using ICEM to improve the mesh quality and using the turbulence model for low Reynolds number flows Transition SST (4 equations) to calculate aerodynamic characteristics such as lift coefficient, drag coefficient, pressure coefficient... find the paths which connect centers of the vortices, and show the contours of pressures and velocities to evaluate the change of centers of the vortices. The results showed that the two vortices grow up and tend to move inward when the attack angle increase, the vortices are broken strongly in high attack angles, the aerodynamic quality of Delta wings change insignificantly when changing turbulent intensity at inlet. This research also carried out that the stall angle increase when increasing the taper ratio.

Aerodynamic characteristics and flow field of delta wings with the canard

Now, many kinds of explorations for outer planets have been proposed around the world. Among them Mars attracts much attention for future exploration. Orbiters and landers have been used for Mars exploration. Recently as a new exploration method, the usage of an airplane has been seriously considered and there are some development projects for Mars airplane. However, the airplane flying on the Earth atmosphere cannot fly on the Mars atmosphere, because atmospheric conditions are much different each other. Therefore, we focused on the usage of the airplane with unfolding wings for Mars exploration. These unfolding wings are designed as delta wings. However, delta wings do not have enough aerodynamics characteristics in a low speed region. In this study, to improve the aerodynamic characteristics of delta wings, we have proposed the usage of canard wings. The purpose of this study is to examine the effectiveness of canard wings to improve aerodynamic characteristics in a low speed region. CFD analysis is performed using four wing models with different canard shapes. The result shows that the usage of canards is effective to improve aerodynamic characteristics of delta wings in a low speed region. In addition, increasing lift coefficient is possible by changing the shape of canards.

Numerical Analysis on Aerodynamic Characteristics of Delta Wing with Variable Geometry Device in Supersonic Flow

Numerical Analysis on Aerodynamic Characteristics of Delta Wing with Variable Geometry Device in Supersonic Flow

앞전 형상에 따른 삼각 날개의 공력 특성

Flow visualization and aerodynamic characteristics of delta wings with two different leading edge geometries are investigated by PIV system and wind tunnel balance when the Reynolds number is about based on the freestream velocity and the root chord length. Delta wing models have 65-deg swept angle, and the leading edge shapes are divided into round- and sharp- type. The experimental results indicated that the leading-edge vortex strength and aerodynamic coefficient in the round leading edge are stronger and more, respectively than those in the sharp one. Therefore the flow interactions between vortices and the boundary layer are more desirable or more rapidly swirled in the round-type leading edge.

Computation of field structure and aerodynamic characteristics of delta wings at high angles of attack

A numerical investigation of the structure of the vortical flowfield over delta wings at high angles of attack in longitudinal and with small sideslip angle is presented. Three-dimensional Navier-Stokes numerical simulations were carried out to predict the complex leeward-side flowfield characteristics that are dominated by the effect of the breakdown of the leading-edge vortices. The methods that analyze the flowfield structure quantitatively were given by using flowfield data from the computational results. In the region before the vortex breakdown, the vortex axes are approximated as being straight line. As the angle of attack increases, the vortex axes are closer to the root chord, and farther away from the wing surface. Along the vortex axes, as the adverse pressure gradients occur, the axial velocity decreases, that is, λ is negative, so the vortex is unstable, and it is possible to breakdown. The occurrence of the breakdown results in the instability of lateral motion for a delta wing, and the lateral moment diverges after a small perturbation occurs at high angles of attack. However, after a critical angle of attack is reached, the vortices breakdown completely at the wing apex, and the instability resulting from the vortex breakdown disappears.

ロールするデルタ翼の非定常空力特性

Vortex flows over rolling delta wings were investigated by flow visualization with oil mist and smoke wire. Compared flow visualization results with force measurements, unsteady aerodynamic characteristics of delta wing were analyzed. Experiments were conducted for two delta wing models with 14 and 7 degree apex half angles, which were forced to oscillate sinusoidally in roll. On the 7 degree apex half angle model, splitting of leading-edge separated vortices were observed in wing roll motion at high angles of attack. Disposition changes of leading-edge separated vortices by splitting induced ta wavy and complicated rolling moment hystagram. The vortex splitting on the slender delta wing is phenomenologically similar to the alternating vortex shedding on the ogive cylinder and to the trailing vortex on the conventional wing trailing-edge.

Baldwin-Lomax factors for turbulent boundary layers in pressure gradients

References Lan, C. E. and Hsu, C. H., of Vortex Breakdown on Longitudinal and Lateral Directional Aerodynamics of Slender Wings by the Suction Analogy, AIAA Paper 82-1385, 1982. Brown, C. E. and Michael, W. H., of Leading Edge Separation on the Lift of a Delta Wing, Journal of Aeronautic Science, Vol. 21, 1954, pp. 690-694. Smith, J. H. B., A Theory of the Separated Flow from the Curved Leading Edge of a Slender Wing, A.R.C. RM 3116, 1959. Werle, H., On Vortex Bursting, ONERA-NT-175, 1971. Wentz, W. H. and Kohlman, D. L., Wind Tunnel Investigations of Vortex Breakdown on Slender Sharp-Edged Wings, NASA-CR98737, 1967. Zohar, Y. and Er-El, J., The Effects of Vortex Breakdown on the Aerodynamic Characteristics of Delta Wings, Technion, Israel Institute of Technology, Aeronautical Research Center, Rept. 0-236, 1984.

Fundamental aerodynamic characteristics of delta wings with leading-edge vortex flows

An investigation of the aerodynamics of sharp leading-edge delta wings at supersonic speeds has been conducted. The supporting experimental data for this investigation were taken from published force, pressure, and flow-visualization data in which the Mach number normal to the wing leading edge is always less than 1.0. The individual upper- and lower-surface nonlinear characteristics for uncambered delta wings are determined and presented in three charts. The upper-surface data show that both the normal-force coefficient and minimum pressure coefficient increase nonlinearly with a decreasing slope with increasing angle of attack. The lower-surface normal-force coefficient was shown to be independent of Mach number and to increase nonlinearly, with an increasing slope, with increasing angle of attack. These charts are then used to define a wing-design space for sharp leading-edge delta wings.

Rarefied Hypersonic Flow Characteristics of Delta Wings and Trailing Edge Spoilers

The present experimental research provides aerodynamic characteristics of delta wings located in a rarefied hypersonic air flow at various angles of attack. Trailing edge spoiler effects are recorded and induced boundary layer separations are investigated. The flow is characterized by a Mach number of 8.1 and a freestream Reynolds number of 2200/cm, simulating roughly a flight altitude of 40 miles. Results include drag and lift coefficients at incidences up to 50°, wall pressure data along the wing center-line, and external flow probing. Visualizations, obtained by means of glow discharge and oil film deposit, allow definition of incident shock such as separation and spoiler induced shock location; the three-dimensional separation spreading is limited upstream from the spoiler for various wing incidences. Data are compared, when possible, with previous experimental results and available theoretical approaches in weak and strong interaction regimes.

Supersonic aerodynamic characteristics of delta wings at high angles of attack

Supersonic aerodynamic characteristics of delta wings at high angles of attack