Wingtip Vortex Control Via Tip-Mounted Half-Delta Wings of Different Geometric Configurations

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
T. Lee ◽  
S. Choi
Keyword(s):  
Tip Vortex ◽  
Delta Wings ◽  
Vortex Control ◽  
Vortex Pattern ◽  
Geometric Configurations ◽  
Wingtip Vortex ◽  
Wing Chord ◽  
Naca 0012 ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The control of the tip vortex, generated by a rectangular NACA 0012 wing, via tip-mounted half-delta wings (HDWs), of different slendernesses Λ, root chords cr, and deflections δ, was investigated experimentally at Re = 2.45 × 105. The results show that regardless of Λ, cr, and δ, the addition of HDWs consistently led to a diffused tip vortex. The degree of diffusion was, however, found to increase with decreasing Λ and cr. HDWs with cr ≤ 50% of the baseline-wing chord c caused a rapid diffusion of vorticity and rendered a weak circulation flowlike tip vortex, suggesting an enhanced wake-vortex decay and alleviation. The cr = 0.5c HDW also produced an improved lift-to-drag ratio. A unique double-vortex pattern also exhibited downstream of the cr ≤ 50%c HDW wings. The interaction and merging of the double vortex were expedited by upward HDW deflection.

Passive Wingtip Vortex Control by Using Tip-Mounted Half Delta Wings in Ground Effect

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Anan Lu ◽  
Tim Lee
Keyword(s):  
Vortex Flow ◽  
Ground Effect ◽  
Tip Vortex ◽  
Secondary Vortex ◽  
Flow Properties ◽  
Delta Wings ◽  
Vortex Control ◽  
Physical Mechanisms ◽  
Induced Drag ◽  
Wingtip Vortex

Abstract The ground effect on the wingtip vortex generated by a rectangular semiwing equipped with tip-mounted regular and reverse half delta wings was investigated experimentally. The passive tip vortex control always led to a reduced lift-induced drag as the ground was approached. In close ground proximity, the presence of the corotating ground vortex (GV) added vorticity to the tip vortex while the counter-rotating secondary vortex (SV) negated its vorticity level. The interaction of the GV and SV with the tip vortex and their impact on the lift-induced drag were discussed. Physical mechanisms responsible for the change in the vortex flow properties in ground effect were also provided.

Wing Tip Vortex Development Under a Grid Generated Turbulent Flow

2018 ◽  
Author(s):  
Kamal Ben Miloud ◽  
Marouen Dghim ◽  
Hachimi Fellouah ◽  
Mohsen Ferchichi
Keyword(s):  
Vortex Core ◽  
Small Variation ◽  
Reynolds Numbers ◽  
Streamwise Velocity ◽  
Stereoscopic Particle Image Velocimetry ◽  
Tip Vortex ◽  
Free Stream Turbulence ◽  
Wingtip Vortex ◽  
Wing Chord ◽  
Naca 0012

The interaction of a NACA 0012 wingtip vortex with a grid-generated flow was investigated in this paper. The experiments were conducted in the near and mid-wakes regions at three free stream turbulence (FST) levels of 0.5% (empty wind tunnel), 3% and 6%, and at two Reynolds numbers, based on the wing chord length, of 2 × 105 and 3 × 105. Stereoscopic Particle Image Velocimetry (SPIV) and hot wire measurements were carried out at four downstream positions, namely x/c = 0.5, 2.5, 5 and 7. Streamwise velocity contours showed that the wingtip vortex decayed with increased FST and downstream distance. In the vortex core region, the streamwise velocity decelerated while the vortex adopted a wake-like profile. FST was found to decrease the vortex circulation, to increase the vortex radius, and to increase the vortex meandering amplitude. By increasing the Reynolds number, the grid cases showed a small variation of the vortex radius and vorticity peak, particularly at downstream positions of 5 and 7. With meandering correction, the turbulence level within the vortex core were found to be reduced as the artificial turbulence induced by the vortex meandering was removed.

scholarly journals A Parametric Study of Trailing Edge Flap Implementation on Three Different Airfoils Through an Artificial Neuronal Network

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 828
Author(s):  
Igor Rodriguez-Eguia ◽  
Iñigo Errasti ◽  
Unai Fernandez-Gamiz ◽  
Jesús María Blanco ◽  
Ekaitz Zulueta ◽  
...  
Keyword(s):  
Aerodynamic Coefficients ◽  
Trailing Edge ◽  
High Lift ◽  
Trailing Edge Flaps ◽  
Artificial Neural Network Ann ◽  
Lift And Drag ◽  
Artificial Neuronal Network ◽  
Naca 0012 ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Trailing edge flaps (TEFs) are high-lift devices that generate changes in the lift and drag coefficients of an airfoil. A large number of 2D simulations are performed in this study, in order to measure these changes in aerodynamic coefficients and to analyze them for a given Reynolds number. Three different airfoils, namely NACA 0012, NACA 64(3)-618, and S810, are studied in relation to three combinations of the following parameters: angle of attack, flap angle (deflection), and flaplength. Results are in concordance with the aerodynamic results expected when studying a TEF on an airfoil, showing the effect exerted by the three parameters on both aerodynamic coefficients lift and drag. Depending on whether the airfoil flap is deployed on either the pressure zone or the suction zone, the lift-to-drag ratio, CL/CD, will increase or decrease, respectively. Besides, the use of a larger flap length will increase the higher values and decrease the lower values of the CL/CD ratio. In addition, an artificial neural network (ANN) based prediction model for aerodynamic forces was built through the results obtained from the research.

scholarly journals Effect of Blade Cambering on Dynamic Stall in View of Designing Vertical Axis Turbines

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Pablo Ouro ◽  
Thorsten Stoesser ◽  
Luis Ramírez
Keyword(s):  
Vertical Axis ◽  
Dynamic Stall ◽  
Hysteresis Cycle ◽  
Aerodynamic Coefficients ◽  
Pitching Motion ◽  
Large Eddy ◽  
Naca 0012 ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Good Agreement

This paper presents large eddy simulations (LESs) of symmetric and asymmetric (cambered) airfoils forced to undergo deep dynamic stall due to a prescribed pitching motion. Experimental data in terms of lift, drag, and moment coefficients are available for the symmetric NACA 0012 airfoil and these are used to validate the LESs. Good agreement between computed and experimentally observed coefficients is found confirming the accuracy of the method. The influence of foil asymmetry on the aerodynamic coefficients is analyzed by subjecting a NACA 4412 airfoil to the same flow and pitching motion conditions. Flow visualizations and analysis of aerodynamic forces allow an understanding and quantification of dynamic stall on both straight and cambered foils. The results confirm that cambered airfoils provide an increased lift-to-drag ratio and a decreased force hysteresis cycle in comparison to their symmetric counterparts. This may translate into increased performance and lower fatigue loads when using cambered airfoils in the design of vertical axis turbines (VATs) operating at low tip-speed ratios.

Control of shock-induced vortex breakdown on a delta-wing-body configuration in the transonic regime

2021 ◽  
pp. 1-25
Author(s):  
Rajan B. Kurade ◽  
L. Venkatakrishnan ◽  
G. Jagadeesh
Keyword(s):  
Vortex Breakdown ◽  
Delta Wing ◽  
Pressure Fluctuations ◽  
Angle Of Attack ◽  
Aerodynamic Coefficients ◽  
Delta Wings ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Sudden Jump ◽  
Modest Level

Abstract Shock-induced vortex breakdown, which occurs on the delta wings at transonic speed, causes a sudden and significant change in the aerodynamic coefficients at a moderate angle-of-attack. Wind-tunnel tests show a sudden jump in the aerodynamic coefficients such as lift force, pitching moment and centre of pressure which affect the longitudinal stability and controllability of the vehicle. A pneumatic jet operated at sonic condition blown spanwise and along the vortex core over a 60° swept delta-wing-body configuration is found to be effective in postponing this phenomenon by energising the vortical structure, pushing the vortex breakdown location downstream. The study reports that a modest level of spanwise blowing enhances the lift by about 6 to 9% and lift-to-drag ratio by about 4 to 9%, depending on the free-stream transonic Mach number, and extends the usable angle-of-attack range by 2°. The blowing is found to reduce the magnitude of unsteady pressure fluctuations by 8% to 20% in the aft portion of the wing, depending upon the method of blowing. Detailed investigations carried out on the location of blowing reveal that the blowing close to the apex of the wing maximises the benefits.

scholarly journals Design and experimental analysis of morphing wing based on biomimicry

2018 ◽  
Vol 7 (3.3) ◽  
pp. 239
Author(s):  
Mugeshwaran A ◽  
Guru Prasad Bacha ◽  
Rajkumar S
Keyword(s):  
Gear Ratio ◽  
Machining Process ◽  
Control Surface ◽  
Cad Model ◽  
Morphing Wing ◽  
Lift And Drag ◽  
Naca 0012 ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Aluminum Material

In this paper narrate about the study of aerodynamics in the multi-section morphing wing variation of baseline configuration to camber con-figuration. In particularly NACA 0012, section tried to morph as NACA 9312 camber section to achieve the lift to drag ratio in the flight condition based on the bio-mimicry. The CAD model and fabricated morphing wing in geometry scale of 20 cm chord and a 36 cm wing-span, with aluminum material ribs divided into 6 sections. Each section was able to rotate approximately 6 degrees without causing a discon-tinuity in the wing surface and also in order avoid the control surface based on the bio mimicry the morphing wing was designed and tested. DC-motor located at main spar with the two equal gear ratio the rib section used to morph the wing through the linear mechanical linkages. The aluminum ribs section are made through the EDM-Wire cut machining process for capable to actuate the morphing wing. In each sec-tion morphing wing can able provide up to 10 percent variation in the symmetrical airfoil to the cambered airfoil. The experimental test of the morphing was carried out in the cascade tunnel by force balancing method and the lift and drag output are compared.  

scholarly journals Effects of Boundary Layer Control Method on Hydrodynamic Characteristics and Tip Vortex Creation of a Hydrofoil

2017 ◽  
Vol 24 (2) ◽  
pp. 27-39
Author(s):  
Parviz Ghadimi ◽  
Araz Tanha ◽  
Navid Nemati Kourabbasloo ◽  
Sasan Tavakoli
Keyword(s):  
Boundary Layer ◽  
Control Method ◽  
Water Injection ◽  
Tip Vortex ◽  
Boundary Layer Control ◽  
Hydrodynamic Characteristics ◽  
Negative Case ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Layer Control

Abstract There is currently a significant focus on using boundary layer control (BLC) approach for controlling the flow around bodies, especially the foil sections. In marine engineering this is done with the hope of increasing the lift - to - drag ratio and efficiency of the hydrofoils. In this paper, effects of the method on hydrodynamic characteristics and tip vortex formation of a hydrofoil are studied. Steady water injection at the tip of the hydrofoil is simulated in different conditions by using ANSYS-CFX commercial software. Validity of the proposed simulations is verified by comparing the obtained results against available experimental data. Effects of the injection on the lift, drag, and lift - to - drag ratio are studied and the ranges within which the injection has the most positive or negative effects, are determined. Furthermore, flow pattern and pressure variation are studied upon the water injection to determine the most positive and negative case and to ascertain the main reasons triggering these phenomena.

Hybrid RANS–LES Simulation of Wingtip Vortex Dynamics

2014 ◽  
Author(s):  
Dmitry Kolomenskiy ◽  
Roberto Paoli ◽  
Jean-François Boussuge
Keyword(s):  
Numerical Simulation ◽  
Turbulence Models ◽  
Numerical Data ◽  
Tip Vortex ◽  
Tip Vortices ◽  
Wingtip Vortex ◽  
Sensitivity Tests ◽  
Rate Of Decay ◽  
Naca 0012 ◽  
Wing Tip

This paper presents a feasibility study of a hybrid RANS–LES approach to numerical simulation of aircraft wing-tip vortices. A NACA 0012 wing is considered for which earlier published experimental and numerical data are available. Mesh sensitivity tests of our RANS solver and comparisons between two different turbulence models indicate that the RANS approach adequately describes the flow upstream from the trailing edge, but overestimates the rate of decay of the wing-tip vortex. A hybrid RANS–LES method is presented that results in a better agreement with the wind tunnel experiment, hence this approach is suggested for numerical simulation of the wake of an airliner.

scholarly journals THE EFFECTS OF ANGLE OF ATTACK, REYNOLD NUMBERS AND WINGLET STRUCTURE ON THE PERFORMANCE OF CESSNA 172 SKYHAWK

2018 ◽  
Vol 10 (1) ◽  
pp. 61
Author(s):  
Henny Pratiwi
Keyword(s):  
Wind Tunnel ◽  
Drag Force ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Balsa Wood ◽  
Wingtip Vortex ◽  
The One ◽  
Lift And Drag ◽  
Drag Ratio ◽  
Lift To Drag Ratio

This research aims to investigate the effects of angle of attack, Reynold numbers and winglet structure on the performance of Cessna 172 Skyhawk aircraft with winglets variation design. Winglets improve efficiency by diffusing the shed wingtip vortex, which reducing the drag due to lift and improving the wing’s lift over drag ratio. In this research, the specimens are the duplicated of Cesnna 172 Skyhawk wing with 1:40 ratio made of balsa wood. There are three different winglet designs that are compared with the one without winglet. The experiments are conducted in an open wind tunnel to measure the lift and drag force with Reynold numbers of 25,000 and 33,000. It can be concluded that the wings with winglets have higher lift coefficient than wing without winglet for both Reynold numbers. It was also found that all wings with winglets have higher lift-to-drag ratio than wings without winglet where the blended 45o cant angle has the highest value.

Some Effects of Thickness on the Longitudinal Characteristics of Sharp-Edged Delta Wings at Low Speeds

1968 ◽  
Vol 72 (686) ◽  
pp. 151-155 ◽  
Author(s):  
L. C. Squire
Keyword(s):  
Aspect Ratio ◽  
Delta Wing ◽  
Leading Edge ◽  
Air Transport ◽  
Wing Area ◽  
Delta Wings ◽  
Amount Of Information ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Passenger Cabin

Recently there has been renewed interest in the concept of an all-wing aircraft as a means of producing cheap air transport over relatively short distances. It is natural that with the large amount of information on slender wings now available an all-wing aircraft based on a sharp-edged slender planform should be considered for this role. One of the difficulties immediately faced in developing this concept is that since the aircraft must carry a large number of passengers it is necessary that as much of the wing area as possible should be deep enough to provide for a large passenger cabin. Thus the wing will be very thick over a large part of its area. If this condition is not met, then the aircraft has too much wing area and hence too high a structure weight. Typically one may think of an aircraft with a delta wing of aspect ratio 2 and with a wing thickness of from 15% to 20% of the root chord over as much of the wing area as possible. At first sight thickness of this order eliminates the main advantage of slender wings since the effect of thickness is usually to reduce the strength of the leading-edge vortices and hence the non-linear lift. Thus the incidence for a given lift is increased above that for a thin wing. This in turn means that the lift-to-drag ratio may be smaller.

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