Analytic and Experimental Investigation of Dihedral Configurations of Three-Winglet Planforms

2008 ◽  
Vol 130 (7) ◽  
Author(s):  
David S. Miklosovic
Keyword(s):  
Aspect Ratio ◽  
Lift Coefficient ◽  
Pitching Moment ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Moment Coefficient ◽  
Velocity Circulation ◽  
Low Speed Wind Tunnel ◽  
Experimental Effort ◽  
Good Agreement

An analytic and experimental effort was undertaken to assess the effectiveness and efficiency of three winglets mounted chordwise to the tip of a rectangular wing. The winglets, with an aspect ratio of 4.6, were mounted on a half-span wing having an effective aspect ratio of 6.29. 13 configurations of varying dihedral arrangements were analyzed with a vortex lattice method and tested in a low-speed wind tunnel at a Reynolds number of 600,000. While the analytic method provided fair agreement with the experimental results, the predicted trends in lift, drag, and (to a lesser degree) pitching moment were in good agreement. The analytic distributions of wake velocity, circulation, and downwash angle verified that highly nonplanar configurations tended to reduce and diffuse the regions of highest circulation and to create more moderate downwash angles in the wake. This was manifest as an overall drag reduction. More specifically, the results showed that the winglets could be placed in various optimum orientations to increase the lift coefficient as much as 65% at the same angle of attack, decrease the drag coefficient as much as 54% at the same lift coefficient, or improve the maximum L∕D by up to 57%. The most dramatic findings from this study show that positioning the winglet dihedral angles had the result of adjusting the magnitude and slope of the pitching moment coefficient. These observations suggest that multiple winglet dihedral variations may be feasible for use as actively controlled surfaces to improve the performance of aircraft at various flight conditions and to “tune” the longitudinal stability characteristics of the configuration.

An Analytic and Experimental Investigation of the Aerodynamic Performance Enhancements of Multiple Winglet Configurations

2005 ◽  
Author(s):  
D. S. Miklosovic ◽  
P. M. Bookey
Keyword(s):  
Aspect Ratio ◽  
Vortex Lattice ◽  
Dihedral Angles ◽  
Pitching Moment ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Moment Coefficient ◽  
Effectiveness And Efficiency ◽  
Low Speed Wind Tunnel ◽  
Experimental Effort

An experimental effort was undertaken to assess the effectiveness and efficiency of three winglets mounted chordwise to the tip of a rectangular wing (NACA 0018 section). The winglets, with an aspect ratio of 3.6, were mounted on a half-span wing having an aspect ratio of 3.1. Twenty configurations of varying dihedral arrangements were analyzed with a vortex lattice method and tested in a low-speed wind tunnel at a Reynolds number of 600,000. In general, the arrangements involving high dihedral angles had lower performance increments, due to lower lift and higher interference drag. More specifically, the results showed that the winglets placed at 60, 45, and 30 degrees, respectively, produced nominal 4% higher lift and 46% lower drag. The most dramatic findings from this study show that positioning the winglet dihedral angles had the result of adjusting the point of maximum L/D and the magnitude of the pitching moment coefficient. These observations suggest that multiple winglet dihedral changes affect the lift, drag, and pitching moment in such a way that they are feasible for use as actively-controlled surfaces to improve the performance of aircraft at various flight conditions and to “tune” the longitudinal stability characteristics of the wing.

scholarly journals Computational Study of a Transverse Rotor Aircraft in Hover Using the Unsteady Vortex Lattice Method

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Juan D. Colmenares ◽  
Omar D. López ◽  
Sergio Preidikman
Keyword(s):  
Vortex Lattice ◽  
Computational Study ◽  
Pitching Moment ◽  
Considerable Influence ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Geometric Configurations ◽  
Hover Flight ◽  
High Reynolds ◽  
The Stability

This paper presents the simulation of a two-rotor aircraft in different geometric configurations during hover flight. The analysis was performed using an implementation of the unsteady vortex-lattice method (UVLM). A description of the UVLM is presented as well as the techniques used to enhance the stability of results for rotors in hover flight. The model is validated for an isolated rotor in hover, comparing numerical results to experimental data (high-Reynolds, low-Mach conditions). Results show that an exclusion of the root vortex generates a more stable wake, without affecting results. Results for the two-rotor aircraft show an important influence of the number of blades on the vertical thrust. Furthermore, the geometric configuration has a considerable influence on the pitching moment.

The Aerodynamics Analysis on Cambered Fuselage Model

2014 ◽  
Vol 660 ◽  
pp. 492-497
Author(s):  
Mohd Zarif bin Md Shah ◽  
Mohd Ridh bin Abu Bakar ◽  
Bambang Basuno
Keyword(s):  
Cross Section ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Circular Cross Section ◽  
Pitching Moment ◽  
Line Thickness ◽  
Moment Coefficient ◽  
Definition Of

There various factors gives influence in determining the fuselage shapes, such as the payload, cockpit, wing and tail placements or in manner up and down loading the payload for a cargo aircraft. These factors may come up the fuselage is no longer as symmetrical fuselage but represent as a cambered fuselage. As results the lift coefficient as well as its pitching moment coefficient is no longer equal to zero as the angle of attack goes to zero. Basically the manner how to determine the fuselage aerodynamics characteristics for cambered fuselage can be done in similar way as in the case of symmetrical fuselage by simply replacing the angle of attack α term with (α-αL=0), where αL=0 represent the angle of attack at zero lift. The present work use a similar manner in determining the zero lift angle of attack as it had been used in DATCOM software. To investigate the effect of camber on the aerodynamics characteristic fuselage, the present work use a fuselage model with a circular cross section where the location of center of the circle placed along the fuselage’s camber line. The fuselage’s camber line defined according to the definition of camber line of NACA airfoils. Aerodynamics analysis on over various fuselage models indicate that the maximum camber line thickness and their position give a significant influent to the fuselage aerodynamics characteristics.

Unsteady aerodynamics investigation of deploying tandem-wing with different methods

2018 ◽  
Vol 233 (10) ◽  
pp. 3714-3733 ◽  
Author(s):  
Hao Cheng ◽  
Hua Wang ◽  
Qingli Shi ◽  
Mengying Zhang
Keyword(s):  
Fore Wing ◽  
Vortex Lattice ◽  
Lift Coefficient ◽  
Unsteady Aerodynamics ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Induced Drag ◽  
Lifting Line ◽  
Lifting Line Method ◽  
Unsteady Lift

In the rapidly deploying process of the unmanned aerial vehicle with folding wings, the aerodynamic characteristics could be largely different owing to the effects of deformation rate and the aerodynamic interference. The investigation on the unsteady aerodynamics is of great significance for the stability analysis and control design. The lifting-line method and the vortex-lattice method are improved to calculate the unsteady aerodynamics in the morphing stage. It is validated that the vortex-lattice method predicts the unsteady lift coefficient more appropriately than the lifting-line method. Different tandem wing configurations with deployable wings are simulated with different deformation rates during the morphing stage by the vortex-lattice method. As results indicated, the unsteady lift coefficient and the induced drag of the fore wing rise with the deformation rate increasing, but it is reversed for the hind wing. Additionally, the unsteady lift coefficient of the tandem wing configuration performs well with a larger stagger, a larger magnitude of the gap and a larger wingspan of the fore wing; however, the total induced drag has a larger value for the configuration that the two lifting surfaces with the same wingspans are closer to each other.

scholarly journals Vortex Lattice Method for the Calculation of the Tip Leakage Flow: Evaluation on a Single Blade

2020 ◽  
Author(s):  
Christophe Montsarrat ◽  
Benjamin Deveaux ◽  
Jérôme Boudet ◽  
Julien Marty ◽  
Eric Lippinois
Keyword(s):  
Vortex Lattice ◽  
Lift Coefficient ◽  
Computation Time ◽  
Computational Effort ◽  
Leakage Flow ◽  
Good Prediction ◽  
Tip Leakage Flow ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Tip Leakage

Abstract This paper investigates the use of a Vortex Lattice Method to simulate tip-leakage flow with small computational effort. The module PyLiSuite presented in the present paper has been completely developed from scratch and is validated on two-dimensional and three-dimensional basic cases. The validation lies on the estimate of the lift coefficient computed from the circulation given by the module. The capabilities of PyLiSuite regarding tip-leakage flow are gauged in comparison with novel experimental measurements on a single blade with an adjustable gap. The results show a good prediction of the shape and size of the tip-leakage vortex for large tip gaps. Differences in the position and the deficit of static pressure in the core of the vortex are noted. The future improvements on the module concern the influence of viscosity to be accounted for and the computation time which could be shortened.

scholarly journals Numerical Investigation on Aerodynamic Characteristics of Damaged Infinite Wings With Variation in Penetration Angle

2020 ◽  
Author(s):  
Bahareh Yahyavi ◽  
Mahmoud Mani ◽  
Habibollah Naddaf
Keyword(s):  
Negative Impact ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Hole Diameter ◽  
Pitching Moment ◽  
Surface Pressure Distribution ◽  
Moment Coefficient ◽  
Pass Through ◽  
Good Agreement

Aerodynamic performance of a full span NACA 641-412 airfoil with a circular-shaped damage at various attack directions has been numerically investigated in this study. To assess the aerodynamic effects of different penetration angles in which threats such as projectiles can pass through the wings, attack directions of 30°, 60°, -30° and -60° relative to the normal axis of the chord line has been studied and compared with attack direction of 0°. To validate with published studies about damaged wing, the 200 mm chord airfoil was simulated with the damage hole diameter of 20% chord at the midspan and midchord location in Reynolds number of 500,000. Quantitative and qualitative results of this numerical study had a good agreement with published experimental data due to appropriate structured mesh and turbulence modelling. In addition to lift, drag and pitching moment coefficient, surface pressure distribution around the damage hole has been studied. Results show that, if the penetration angle becomes more negative, aerodynamics performance of the wing will be further decreased; therefore, attack directions of threat mechanisms such as “ahead and above” or “below from the rear” have severe negative impact than other directions on aerodynamic performance of the damaged infinite wing.

Hydrodynamical Analysis on the Arrow

2014 ◽  
Vol 644-650 ◽  
pp. 527-530
Author(s):  
Ji He Zhou ◽  
Xiao An Long
Keyword(s):  
Lift Force ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Wind Tunnel Test ◽  
Static Stability ◽  
The State ◽  
Pitching Moment ◽  
Moment Coefficient ◽  
Attached Flow ◽  
Main Components

The water tunnel and wind tunnel test carried on the arrow aims to have a better understanding of the hydrodynamics performance of arrows and to improve the technical knowledge of the archery movement Through the experimental research, we can draw conclusions as follows: within the range of angle of attack ( -6°---6°), the arrow can keep the state of attached flow: The state of flow of the arrow with spiral plastic pinna is better than that of arrow with straight one; Within the experimental angle of attack, the lift coefficient Cy will become larger with the pitching moment coefficient Mz getting smaller with the increase of the angle of attack. The arrow has the vertical static stability; with or without arrow feather will have great impact on lift force Y and pitching moment coefficient Mz; the feather rolling will have some impact on lift coefficient Cy, The arrow feather is the main components to produce lift force Y and to give the arrow body relatively great static stability.

scholarly journals Effects of Bio-Inspired Surface Roughness on a Swept Back Tapered NACA 4412 Wing

2019 ◽  
Author(s):  
Khurshid Malik ◽  
Mohammed Aldheeb ◽  
Waqar Asrar ◽  
Sulaeman Erwin
Keyword(s):  
Surface Roughness ◽  
Leading Edge ◽  
Pitching Moment ◽  
Sweep Angle ◽  
Moment Coefficient ◽  
Minimum Drag ◽  
Roughness Elements ◽  
Pros And Cons ◽  
Stall Angle ◽  
Low Speed Wind Tunnel

This paper presents the overall pros and cons of the effect of surface roughness elements over a NACA 4412 tapered, swept back half wing with a sweep angle of 30º and a dihedral angle of 5º. The tests were conducted at a Reynolds number of 4 × 105 in the IIUM Low Speed wind tunnel. Different roughness sizes and roughness locations were tested for a range of angle of attack. Lift, drag and pitching moment coefficients were measured for the smooth wing and with roughness elements. Surface roughness delays the stall angle and decreases the lift. The wing with the roughness elements located at 75% to 95% of mean chord from leading edge shows minimum drag and maximum lift compared to other locations. Significant increase in the pitching moment coefficient was found for flexible roughness elements. In case of rigid surface roughness, the effect on pitching moment is small.

Numerical Calculation of a Missile's Aerodynamic Characteristic

2011 ◽  
Vol 186 ◽  
pp. 220-224
Author(s):  
Chun Guo Yue ◽  
Xin Long Chang ◽  
You Hong Zhang ◽  
Shu Jun Yang
Keyword(s):  
Numerical Calculation ◽  
Drag Coefficient ◽  
Numerical Computation ◽  
Aerodynamic Characteristic ◽  
Lift Coefficient ◽  
Shape Design ◽  
Pitching Moment ◽  
Moment Coefficient ◽  
Mach Numbers ◽  
In Virtue Of

In virtue of Fluent of CFD software, numerical computations of aerodynamics of an air-to-air missile in different mach numbers and different attack angles were carried though. The movement trends of lift coefficient, drag coefficient and pitching moment coefficient with variety of mach numbers and attack angles were gained, meanwhile, distributing trends of pressure, temperature and weather velocity were also obtained. The results indicated that the basis and references could be offered by numerical computation results for shape design of missile and definite preponderances were showed than traditionary numerical computation methods.

Aerodynamics Analysis on Unsymmetrical Fuselage Models

2013 ◽  
Vol 315 ◽  
pp. 273-277
Author(s):  
Mohd Ridh bin Abu Bakar ◽  
Bambang Basuno ◽  
Sulaiman Hasan
Keyword(s):  
Cross Section ◽  
Strong Influence ◽  
Lift Coefficient ◽  
Circular Cross Section ◽  
Longitudinal Axis ◽  
Pitching Moment ◽  
Moment Coefficient ◽  
Symmetrical Body ◽  
Semi Empirical ◽  
Plat Form

The large commercial passengers airplanes are mostly designed to have symmetrical body with respect to the longitudinal axis. However for small passengers airplanes or for the airplane designed as UAV plat form is normally having an unsymmetrical fuselage. The aerodynamics characteristics fuselage may give a strong influence to the overall aerodynamics characteristics of the airplane. The present work investigates the aerodynamics characteristics of the unsymmetrical fuselage with respect to the longitudinal axis. The fuselage assumed to have circular cross section and the coordinate of the fuselage are created by using the same equation which had been used in defining the coordinate of cambered airfoil NACA series four digits. The fuselage had been set to have the same maximum thickness 15 % of the fuselage length and different fuselage models are obtained through varying the position as well as the value of the maximum camber line. The semi empirical aerodynamic method for estimating the fuselage lift coefficient CL, drag coefficient CDand the fuselage pitching moment coefficient CMsuch as given by DATCOM are well established. However when it came to the unsymmetrical fuselage, this approach can not be adopted easily. The required of angle attack at zero lift of the corresponding unsymmetrical fuselage is difficult to define. The result for particular cambered fuselage indicates that the aerodynamics characteristics strongly influenced by how the fuselages camber lines look likes.

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