Swept-back Wing Research Articles

Investigation of various winglets using computational fluid dynamics for subsonic aircraft

Abstract The tiny, upturned, or downturned extensions at the tips of an aircraft’s wings are designated as winglets. By minimizing drag and improving fuel efficiency, they are introduced to increase the aircraft’s aerodynamic efficiency. Winglets are now a day’s employed in the commercial aircraft to minimise the induced effect caused by wing tip vortices produced at low subsonic speeds. In this article, we have selected NACA 2412, from which we have created a swept back wing with a 20-degree sweep angle that has eight distinct winglet configurations. SolidWorks 2023 is used for design work, and ANSYS 19.2 is used for analysis. The analysis is carried out by changing the angle of attack (AOA) from -6 degrees to 20 degrees with an incremental step of 2 degrees. Here, we have used the k-epsilon turbulence model to capture the turbulence and 100 m/s velocity is maintained throughout the analysis. From this analysis, a potential solution of aerodynamic co-efficient (lift, drag, cl, cd and cl/cd) are being observed. Blended winglet with cant angle 35 degrees produces high lift-to-drag ratio compared with another winglet configuration. The insights gained from the study are plotted in various graphs such as cl vs alpha, cd v/s alpha and cl/cd v/s alpha and the CFD results show a considerable improvement in aircraft’s performance after using winglets. Aluminium alloy’s high strength to weight ratio, robust corrosion resistance, enhanced conductivity, and outstanding ductility qualities will make it easier for us to manufacture winglets in the future.

A Jacobi-Ritz Approach for Aeroelastic Analysis of Swept Distributed Propulsion Aircraft Wing

Abstract This paper presents a Jacobi-Ritz approach for conducting flutter and divergence analysis of a complex distributed propulsion aircraft wing like NASA X-57. The general orthogonal Jacobi polynomials are used to approximate the bending displacement and torsional rotation angle in the Ritz method based structural and aeroelastic analysis. The Jacobi polynomials satisfy the orthogonality condition using weight functions which are easily modified to satisfy different essential and natural boundary conditions. Compared to simple polynomials, Jacobi polynomials can eliminate the well-known ill-conditioning numerical issues when considering higher-order polynomials. The Jacobi-Ritz method is also found to alleviate mode switching often encountered in tracking the changes of modes with the varying airspeed. The Jacobi-Ritz method is later used to investigate the flutter and divergence speeds under distributed propulsor mass and their locations, nonuniform aerodynamic model in the presence of multiple propulsors, and the sweep angle. Results show that placing the distributed propulsors on the wing's leading edge increases the flutter speed even though the bending and torsion modal frequencies are decreased compared to those of the wing without propulsors. The presence of pods for the middle high-lift motors causes an extra aerodynamic moment which reduces the flutter speed. Parametric studies also show that the divergence speed is lower than the flutter speed for a uniform and straight distributed propulsor wing. Using swept-back wing configuration and placing the tip propulsor near the wing's leading edge can help to increase both flutter and divergence speeds.

A Comparative Study on the Efficiencies of Aerodynamic Reduced Order Models of Rigid and Aeroelastic Sweptback Wings

A Comparative Study on the Efficiencies of Aerodynamic Reduced Order Models of Rigid and Aeroelastic Sweptback Wings

The effect of vortex generators having Clark-Y airfoil on tapered swept-back wing

In the experimental study, the effects of vortex generators (VGs) having Clark-Y airfoil and triangular VGs are investigated. The tests were carried out on a tapered swept-back wing at Re = 6.0×104 using counter-rotating vortex generators having Clark-Y airfoil at five different locations that are x/c= 0.1, 0.2, 0.3, 0.4, and 0.5 and triangular VGs at x/c=0.1 location. A load cell is used to measure forces at angles of attack (AoA) ranging from 0° to 30°. It is observed that the maximum lift coefficient (CLmax) and aerodynamic performance of VGs having Clark-Y airfoil decrease when the position of the vortex generators changes from 0.1 to 0.5. The optimal results obtained from the study show that the tapered swept-back wing with the VGs having Clark-Y airfoil exhibits a significant increase of 37.5% in the CLmax and approximately 55% in the lift to drag ratio (L/D) at x/c=0.1 compared to the baseline. At low AoA, the VGs having Clark-Y airfoil provided better lift, whereas at high AoA, the triangular VGs provided better lift.

Design of a new sweptback wing for a future supersonic aircraftResearch on lift drag characteristics and aerodynamic analysis

In recent years, with the gradual development of the aviation industry, how to make supersonic aircraft truly used in military air defense has become a global problem. In this paper, the wing design of supersonic aircraft is studied, a swept back symmetrical wing suitable for supersonic reconnaissance aircraft is designed with reasonable aspect ratio, span length, sweep angle, thrust weight ratio and wing load. On the basis of the aerodynamic characteristics of the aircraft analyzed, the inboard electron, outboard electron, flasheron, leading edge flap and all moving tip are designed to ensure the controllability in the flight line and to maintain the balance and stability of the aircraft. The qualitative analysis of the flight performance of the wing is also performed. This paper provides a possibility for the design of supersonic aircraft in the future.

The performance and application of sweep wing aircraft

With the development of science and technology, more and more civil and military aircraft have adopted swept-back wing shapes. this paper explores the relationship between the angle of swept-wing and the lift, drag and lift-drag ratio of the aircraft, and expounds it in combination with the actual swept-wing aircraft, such as Boeing737 and MIG-23 to find the best sweep angle of the aircraft in the appropriate range and analyze the effect of swept wing angle on flight speed. This paper studies and analyzes the data through literature retrieval and data processing and cites data models from many academic journals. The experimental data are mainly derived from computational fluid dynamics and wind tunnel simulation. This paper finds that a wider sweep angle can result in better aerodynamic performance, suited for supersonic flight, while a smaller sweep angle can result in a better lift-drag ratio, it is suitable for takeoff and landing of aircraft and low-speed flight attitude.

Proposed Modification to Increase Main Swept Back Wing Efficiency for Aircraft Aermacchi Siai S211

A winglet is devices attached at the wing tips, used to improve aircraft wing efficiency by reduction influence wing tips vortices and induct drag, increasing lift force at the wing tips and effective aspect ratio without adding greatly to the structural stress and weight in the wing structure. This paper is presented three-dimensional numerical analysis to proposed modification swept back wing by adding Raked winglets devices at the main wing tips belong the two seat trainer aircraft type Aermacchi Siai S211 by using Fluent ANSYS 13 software. CFD numerical analysis process was performed at the same flight boundary conditions indifferent wing angle of attacks with constant air flow velocity V∞ =50 (m/sec), ambient pressure Po=101325 (Pa), ambient temperature To=288.14 (K), and at air density ρo=1.225 (kg\m3) to both proposed wing model and the main aircraft wing model. The results are shown an improvement in aerodynamic parameters including increment lift coefficient to (0.22%-5.95%), reduction drag coefficient to (0.34% - 3.60%), increment wing load efficiency ratio to (2.62% - 7.30%), reduction induct drag coefficient CDi to (7.65% - 13.11%) compared with the main aircraft wing model and achieved an improvement in aircraft flight maneuver abilities and stability controls especially during descent, approach, landing and takeoff with lower speed with shortage runway.

Hydrodynamic Shape Design and Self-Propulsion Analysis of a Hybrid-Driven AUG

Due to the lack of a powerful propulsion device in conventional autonomous underwater gliders (AUGs), their mobility and flexibility are insufficient, thus not being capable of also ensuring the stability of the motion route. Thus, it is necessary to further develop hybrid-driven AUGs. This paper applied CFD simulation and experimental analysis methods to study and design a hybrid-driven AUG with a propeller optimized from a type of AUG with swept-forward and swept-back wings. Through parameter adjustment, the hydrodynamic configuration was optimized, and the optimal hull design and hydrofoil type selection were proposed. The lift–drag ratio could be improved by up to 22.5% at an angle of attack of 8 degrees. The optimized AUG was combined with a single propeller for self-propulsion simulation. Aiming at the problem caused by the propeller torque on the AUG, the strategy of a contra-rotating propeller (CRP) was conducted to self-eliminate the propeller torque. The simulation results show that in the self-propulsion state, the torque of the contra-rotating propeller could be reduced by more than 92% compared with that of a single propeller, greatly reducing the impact on the hybrid-driven AUG and raising the navigation stability.

Proof-of-Concept Study of Flexible Lattice Variable Sweptback Wing

This paper presents a flexible lattice variable sweptback wing (FLVSW) concept based on the flexible main beam and lattice that allows the sweptback angle to be varied by 80 deg. The whole FLVSW concept is an integral structure consisting of rigid and flexible parts. The rigid parts are the wing ribs that maintain the shape of the wing and transfer the aerodynamic loads. The flexible parts are mainly composed of the flexible main beam and the flexible lattice, which meet the requirements of supporting aerodynamic loads and deformation of the wing. The surface of the FLVSW is divided into parallel partitions by the wing ribs, and each partition is closed by superimposed skin strips. A prototype model was designed and manufactured based on the Talon first-person-view (FPV) platform performance parameters and considering the finite element analysis of the FLVSW concept under the effect of the drive mechanism and aerodynamic loads. Through testing the structural response of the manufactured prototype model under the driving and static deadweight loads, it was demonstrated that the structure could be driven smoothly and exhibited no deleterious deformations at various sweep angles. In this way, the feasibility of the FLVSW drive mechanism and the design process was verified.

Theoretical and Computational Investigation on Swept Back Wing using CFD Method

The principles of flight deals with the motion of air and forces acting on an aircraft. The theoretical aspects of aircraft deals with four different forces. The main aim of the study was to analyse the Swept Back Wing for Supersonic and Hypersonic Mach Regimes at various angles of attack. The geometry and analysis were done using Ansys-Fluent. Calculations were done for constant air velocity altering only the angle of attack. The findings present up the contours of pressure and velocity along with evaluation of lift, drag and its coefficients

Auto Sweptback Wing Based on Low Scattering Demand for an Unmanned Aerial Vehicle in Phase Flight

In order to study the optimal sweepback angle when a variant unmanned aerial vehicle (UAV) exhibits a low radar cross-section (RCS) indicator during phase flight, an auto sweep scheme based on electromagnetic scattering evaluation and an improved particle swarm optimization algorithm was presented in this article. An aircraft model with variable swept wings was built, and high-precision grids were used to discretize the target surface. The results showed that the optimal sweep angle did not change with the increase in the initial azimuth angle when the observation field was horizontal and the ending azimuth was 90°. While the increase in the elevation angle affected the optimal sweepback angle of the aircraft under the given conditions, when the observation initial azimuth angle was 90°, the auto sweep scheme could reduce the mean and some minima of the RCS indicator curve of the aircraft and could provide the aircraft with an optimal sweep angle under different observation conditions. The presented method was effective in learning the optimal sweep angle of the aircraft when low scattering characteristics were required during the phase flight.

The leading-edge vortex over a swift-like high-aspect-ratio wing with nonlinear swept-back geometry

The leading-edge vortex (LEV) is a common flow structure that forms over wings at high angles of attack. Over the years, LEVs were exploited for augmenting the lift of man-made slender delta wings aircraft. However, recent observations suggested that natural flyers with high-aspect-ratio (high-AR) wings, such as the common swift (Apus apus), can also generate LEVs while gliding. We hypothesize that the planform shape and nonlinear sweep (increasing towards the wingtip) enable the formation and control of such LEVs. In this paper, we investigate whether a stationary LEV can form over a nonlinear swept-back high-AR wing inspired by the swift’s wing shape and evaluate its characteristics and potential aerodynamic benefit. Particle image velocimetry (PIV) measurements were performed in a water flume on a high-AR swept-back wing inspired by the swift wing. Experiments were performed at four spanwise sections and a range of angles of attack for a chord-based Reynolds number of . Stationary LEV structures were identified across the wingspan by utilizing the proper orthogonal decomposition (POD) method for angles of attack of 5∘–15∘. The size and circulation of the stationary LEV were found to grow towards the wingtip in a nonlinear manner due to shear layer feeding and spanwise transport of mass and vorticity within the LEV, thus confirming that nonlinear high-AR swept-back wings can generate stationary LEVs. Our results suggest that the common swift can generate stationary LEVs over its swept-back wings to glide slower and at a higher rate of descent, with the LEVs potentially supporting up to 60% of its weight.

Numerical Study of Blended Winglet Geometry Variations on Unmanned Aerial Vehicle Aerodynamic Performance

An unmanned aerial vehicle (UAV) is an unmanned aircraft that can be controlled remotely or flown automatically. Nowadays, the use of UAVs is extensive, not only limited to the military field but also in civilian tasks such as humanitarian search and rescue (SAR) tasks, railroad inspections, and environmental damage inspections. Therefore, study on UAV becomes essential to answer the challenges of its increasingly widespread use. This study explores the addition of a blended winglet on the swept-back wing of the UAV. It is to predict the effect of the aerodynamic performance. The backpropagation neural network (BPNN) method helps to predict the aerodynamic performance of the UAV in the form of a lift-drag coefficient ratio (C L /C D ) and drag coefficient at 0 O angle of attack (CD 0 ). It is based on blended winglet parameters such as height, tip chord, and cant angle. The obtained BPNN modeling has a network architecture of 3 inputs, 2 hidden layers, and 1 output with a mean square error (MSE) of 4.9462e-08 and 4.4756e-06 for the relationships between blended winglet parameters with C L /C D and CD 0 , respectively.

Multiband Imaging of the HD 36546 Debris Disk: A Refined View from SCExAO/CHARIS*

Abstract We present the first multiwavelength (near-infrared; 1.1–2.4 μm) imaging of HD 36546's debris disk, using the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system coupled with the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS). As a 3–10 Myr old star, HD 36546 presents a rare opportunity to study a debris disk at very early stages. SCExAO/CHARIS imagery resolves the disk over angular separations of ρ ∼ 0.″25–1.″0 (projected separations of rproj ∼ 25–101 au) and enables the first spectrophotometric analysis of the disk. The disk’s brightness appears symmetric between its eastern and western extents, and it exhibits slightly blue near-infrared colors on average (e.g., J−K = −0.4 ± 0.1)—suggesting copious submicron-sized or highly porous grains. Through detailed modeling adopting a Hong scattering phase function (SPF), instead of the more common Henyey–Greenstein function, and using the differential evolution optimization algorithm, we provide an updated schematic of HD 36546's disk. The disk has a shallow radial dust density profile (α in ≈ 1.0 and α out ≈ −1.5), a fiducial radius of r 0 ≈ 82.7 au, an inclination of i ≈ 79.°1, and a position angle of PA ≈ 80.°1. Through spine tracing, we find a spine that is consistent with our modeling, but also with a “swept-back wing” geometry. Finally, we provide constraints on companions, including limiting a companion responsible for a marginal Hipparcos–Gaia acceleration to a projected separation of ≲0.″2 and to a minimum mass of ≲11 M Jup.

Characteristics of Separation and Induced Drag in the Use of Swept-back Wing Unmanned Aerial Vehicle

The swept-back wing has been used in almost all aircraft wings. This is necessary to reduce the pressure drag from the wings so that there is an increase in aerodynamic performance. The aerodynamic performance is the ratio between the total drag coefficient and the lift coefficient. This research attempts to explain the swept-back wing phenomenon in unmanned aerial vehicles (UAV) on Eppler 562 airfoil. The numerical simulation uses the k-ε turbulent model at Reynolds number (Re) = 2.34 x 104. Variation of backward swept angle Λ = 0°, 15°, and 30°. The separation growth Λ = 0° occurred more on the wing root, while Λ = 15° and Λ = 30° occurred more on the wingtip. At Λ = 15°, as the angle of attack increases, the area of the separation increases, and the area of the transition towards the separation decreases. The reattach area also has an increase in the area of the trailing edge. At Λ = 30°, with an increase in the angle of attack, there is a shift from the wingtip area to the mid-span. The area of separation and transition to separation has increased significantly. The re-attach area at α = 8o has not been seen, so at α = 12o it has been seen significantly. The vorticity on the x-axis shows Λ = 15°, and Λ = 30° has a wider area while on the z-axis, Λ = 15°, and Λ = 30° have stronger vortex strength. However, in the mid-span, Λ = 0° has a stronger result.

Flow simulation of the flight manoeuvres of a large transport aircraft with load alleviation

AbstractA new method for predicting manoeuvre loads on a large transport aircraft with a swept-back wing and a load alleviation system based on control surface deflections is developed. For this purpose, three-dimensional Reynolds-averaged Navier–Stokes (RANS) simulations of the rigid wing–fuselage configuration are performed while the aerodynamics of the tailplane are estimated by means of handbook methods. For a closer analysis, different quasi-steady pitching manoeuvres are chosen based on the CS-25 regulations. One of these manoeuvres is also simulated with active load alleviation, leading to a reduction in the wing-root bending moment by more than 40%. Besides demonstrating the potential of the considered load alleviation system, it is shown which manoeuvres are especially critical in this context and which secondary effects come along with load alleviation.

Aerodynamic performance investigation of sweptback wings with bio-inspired leading-edge tubercles

The aerodynamic behavior of sweptback wing configurations with bio-inspired humpback whale (HW) leading-edge (LE) tubercles has been investigated through computational and experimental techniques. Specifically, the aerodynamic performance of tubercled wings with symmetric (NACA 0015) and cambered (NACA 4415) airfoils is validated against the baseline model at various angles of attack ([Formula: see text]. The [Formula: see text]/[Formula: see text] ratio of the HW flipper is strategically reduced to 0.15 for ascertaining the flow control potential of the bio-inspired wings with sweptback configuration. It is a novel effort to quantify the effect of the leading-edge protuberances on stall delay, flow separation control and distribution of streamline vortices at unique [Formula: see text]/[Formula: see text] ratio outside the thickness range of HW flipper morphology. Four tapered sweptback wing models (Baseline A, Baseline B, HUMP 0015, HUMP 4415) are used with the amplitude-to-wavelength ([Formula: see text] ratio of 0.24 and Reynolds number about [Formula: see text]. The chordwise pressure distributions are recorded at the peak, mid and trough regions of the tubercled wings through a detailed wind tunnel testing and validated with numerical analysis. Additionally, the flow characteristics over the bio-inspired surfaces have been qualitatively analyzed through the laser flow visualization (LFV) technique to reveal the influence of laminar separation bubbles (LSBs). The essential aerodynamic characteristics such as boundary layer trip delay, vortex mixing, stall delay, and flow control at different AoA are addressed through consistent experimental data. As the sweptback configuration is a primary choice for airplane wings, the improved aerodynamic characteristics of the tubercled wings can be effectively utilized for the design of novel lifting surfaces, hydroplanes and wind turbines in the near future.

Propagation of stationary and traveling waves in a leading-edge boundary layer of a swept wing

The transition characteristics around the leading edge of a swept-back wing shape were numerically investigated. We conducted direct numerical simulations (DNSs) of a swept-wing shape with a high Reynolds number Re=Rec/cos Λ=5.85×106 based on the chord length with a sweep angle Λ=70°. In the study, a randomly distributed impulsive local body force was applied at the wall to encourage a transition. Through impulsive local forcing, two coherent waves formed in both an attachment line and a three-dimensional boundary layer: A stationary elongated streak structure in the external flow direction and a traveling wave in the sweep direction. These characteristics in the attachment line were slightly different from those in the three-dimensional boundary layer. We computed the nonmodal transient energy growth for the present leading-edge boundary layer and compared the coherent waves observed in the DNSs. The stationary and traveling modes in the DNSs are found to be in a transient growth group; these modes temporally grow to the maximum in the short target time (τ<0.02). One of our conclusions is that both waves occurring in the present attachment line are strongly related to the short-term transient energy growth phenomena of the nonorthogonality of the flow field. When the roughness forcing was gradually increased, the traveling wave was not generated, whereas the stationary wave was. This was considered because the present attachment-line boundary layer was receptive to a small disturbance and more likely to generate a stationary wave than a traveling wave.

Size effects of vane-type rectangular vortex generators installed on high-lift swept-back wing flap on lift force and flow fields

Size effects of vane-type rectangular vortex generators installed on high-lift swept-back wing flap on lift force and flow fields

Aerodynamics with state-of-the-art bioinspired technology: Tubercles of humpback whale

Bioinspired aerodynamics is an emerging subject in the design of advanced flight vehicles with superior performance and minimum fuel consumption. In the present review article, a comprehensive evaluation is focused on previous studies and investigations toward the performance enhancement of aerodynamic surfaces with leading-edge (LE) tubercles. The implementation of tubercles has been biologically imitated from humpback whale (HW) flippers. Particularly, aerodynamicists are much interested in this bioinspired technology because of the exclusive maneuvering and flow control potential of HW flippers. LE protuberances are considered as a passive flow control method to improve the aerodynamic performance in various applications like aviation, marine, and wind energy. The aerodynamic and hydrodynamic performance variations caused by specific tubercles amplitude and wavelength are also compared through numerical and wind tunnel testing. The prospective utilization of tubercles on boundary layer flow control is measured with regard to conventional and swept-back wing designs. Flow control mechanisms of tubercles are outlined with several interesting facts in addition to the outcomes of various bioinspired aerodynamic investigations in the recent years.