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Journal articles on the topic 'Circular Wing'

Author: Grafiati

Published: 4 June 2021

Last updated: 14 February 2022

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1

Segal, Zelik. "Hydrodynamic Characteristics of Wings in Circular Motion." Journal of Ship Research 46, no. 02 (June 1, 2002): 92–98. http://dx.doi.org/10.5957/jsr.2002.46.2.92.

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Hydrodynamic characteristics of wings in circular motion are determined at present very approximately, as a rule, according to the solution of the problem on streamlining the wing by a small curvature nonviscid potential. However, in some practical cases the radius of the wing trajectory is of the same order of magnitude as the wing chord. That is why there is a necessity for a more correct determination of wing hydrodynamic characteristics, accounting for the relatively large curvature of the wing trajectory and the and viscosity. This paper presents a description and results of our theoretical and experimental investigation of the hydrodynamic characteristics of wings in a wide range of relative radiuses of their motion.

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2

Ali, Suliman M. M., Ashraf A. Omar, Waleed Fekry Faris, Ahmad Faris Ismail, and J. S. Mohamed Ali. "Aerodynamics of a circular planform wing." IOP Conference Series: Materials Science and Engineering 488 (March 19, 2019): 012005. http://dx.doi.org/10.1088/1757-899x/488/1/012005.

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3

Yamamoto, Yuzo. "Induced drag of a wing in a circular wind tunnel." AIAA Journal 30, no. 9 (September 1992): 2344–46. http://dx.doi.org/10.2514/3.11227.

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4

Iosilevskii, G. "Asymptotic theory of high-aspect-ratio arched wings in steady incompressible flow." Journal of Fluid Mechanics 303 (November 25, 1995): 367–77. http://dx.doi.org/10.1017/s0022112095004307.

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Asymptotic theory of high-aspect-ratio wings in steady incompressible flow is extended to a case where the wing forms either an open or closed circular arc. The generalization is based on an integral formulation of the problem, which resembles the one used by Guermond (1990) for a plane curved wing. A second-order approximation is obtained for the load distribution on two model wings, one resembling that of a gliding parachute, and the other resembling a short duct.

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5

Mat Taib, C. F., Abdul Aziz Jaafar, and Salmiah Kasolang. "Numerical Study of Winglet Cant Angle Effect on Wing Performance at Low Reynolds Number." Applied Mechanics and Materials 393 (September 2013): 366–71. http://dx.doi.org/10.4028/www.scientific.net/amm.393.366.

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The study on the effect of winglet shape in wing design has been a focus of many researchers. Nevertheless, the effect of cant angle on the wing performances at low Reynolds number has not been fully explored. This paper describes the effect of a single semi-circular shaped winglet attached with a rectangular wing model to lower the drag without increasing the span of the wing. Aerodynamic characteristics for the rectangular wing (NACA 65-3-218) with and without semi-circular winglets have been studied using STAR CCM+ 4.0. This numerical analysis is based on Finite Volume Approach. Simulations were carried out on the rectangular wing model with and without winglet at aspect ratio of 2.73 and Reynolds number of 0.16 x 10 6 for various angles of attack. From the numerical analysis, wing performance characteristics in terms of lift coefficient CL, drag coefficient CD, and lift-to-drag ratio, CL/CD were obtained. It was found that the addition of a semi-circular winglet has resulted in a larger lift curve slope and higher Lift-to-Drag ratio in comparison with the case of a wing without winglet. Further investigation has revealed that a wing with semi-circular winglet with cant angle of 45 degree has produced the best Lift-to-Drag ratio, CL/CD.

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6

Datt, Ravi, Mangal Bhist, Alok Kothiyal, Rajesh Maithani, and Anil Kumar. "Fluid flow and heat transfer enhancement in wings with combined solid ring twisted tape inserts circular heat exchanger tube." Thermal Science 23, no. 6 Part B (2019): 3893–903. http://dx.doi.org/10.2298/tsci170613095d.

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Experimental examination is carried out to study the turbulent heat transfer and fluid-flow characteristics in circular heat exchanger tube using combined wing with solid ring twisted tape inserts. A series of experiments has been performed with the range of Reynolds number varied from 3000 to 21000, number of twisted taped inserts, NTT, varied from 1.0 to 4.0 with constant value of other twisted tape parameters such as rings pitch ratio, dR /DT = 1.0, wing pitch ratio, PW /WT = = 3.0, and wing depth ratio, Wd /WT = 1.67. Based on the examined, turbulent heat transfer and fluid-flow in wing with combined solid ring twisted tape inserts results are compared with plain circular tube under same operating conditions. The experimental results show that the heat transfer is increased around 5.66 times than plane circular heat exchanger tube. The thermal and hydrodynamic performance parameter based on equal pumping power, ?p, was found to be highest for NTT = 3.0. The optimum value of thermal and hydrodynamic performance has been found to be 2.74 for Reynolds mumber of 3000 within the range of the parameters investigated. Multiple wings with solid rings twisted tape inserts have been also shown to be thermally as well as hydraulically better in comparison to other similar twisted tape insert geometries.

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7

Kenyon, Kern E. "Lift Force on a Circular Arc Wing." Natural Science 09, no. 10 (2017): 351–54. http://dx.doi.org/10.4236/ns.2017.910033.

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8

TANAKA, Masaki, Takashi MATSUNO, and Hiromitsu KAWAZOE. "312 CFD Analysis around Circular Ring Wing." Proceedings of Conference of Chugoku-Shikoku Branch 2006 (2006): 103–4. http://dx.doi.org/10.1299/jsmecs.2006.103.

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9

YAMAMOTO, Yuzo. "Minimum Induced Drag of a Wing in a Circular Open Wind Tunnel." Journal of the Japan Society for Aeronautical and Space Sciences 40, no. 456 (1992): 23–27. http://dx.doi.org/10.2322/jjsass1969.40.23.

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10

KATO, Masahiro, Kazuaki KAWAUCHI, Satoshi KIKUCHI, Shigeki IMAO, and Yasuaki KOZATO. "Wing in Grand Effect of Circular-Arc Aerofoiles." Proceedings of Conference of Tokai Branch 2017.66 (2017): 407. http://dx.doi.org/10.1299/jsmetokai.2017.66.407.

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11

Mahesh Babu, T. S., D. Sairaja, A. Chandrasekar, and S. Sreenathreddy. "Computational Analysis of Different Shapes of Dimple on Wing." Applied Mechanics and Materials 766-767 (June 2015): 1061–69. http://dx.doi.org/10.4028/www.scientific.net/amm.766-767.1061.

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Dimple is a slight indentation in a surface. Dimples create turbulence by creating vortices which delays the boundary layer separation resulting in decrease of drag, increasing aerodynamic efficiency, manoeuvrability and also the angle of stall. The present work focused on the understanding of the effect of dimples on boundary layer separation, lift, drag, critical angle of attack, aerodynamic efficiency of wings. The airfoils without any dimples and with circular dimples as inward and outward on are studied. Types of dimples considered in 3D studies are circular and octagon dimple then computational analysis is done using ANSYS FLUENT CFD software, applying subsonic flow, in three dimensional co-ordinate system. The results are compared with a straight wing without dimples. Then suggestions and conclusions are made.

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12

Umezu, Shinjiro, Naoyuki Tanabe, and Hiromu Hashimoto. "Fabrication of Comb Shape of Leading Edge Wing of Dragonfly." Key Engineering Materials 625 (August 2014): 182–86. http://dx.doi.org/10.4028/www.scientific.net/kem.625.182.

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Research on Micro air vehicle (MAV) has been carried out by many researchers to gather information in environmental monitoring, security and so on. When the earthquake, fire, smoke take place, it is difficult for human beings to investigate the detail because of dangerous condition. However, MAV has possibility to investigate the detail because MAV can fly freely around. Recently, dragonfly is highly focused by many researchers because dragonfly has high flight performances those are high efficiency flight, unintended acceleration, rapid turn and hovering. In general, these characteristics have root that wing is corrugation shape. We focus on microstructures on wing and its aerodynamic characteristics because there are many unique microstructures. We focused on micro spikes on dragonfly wing. Over three thousands of spikes exist on two sides of wing. The length and shape of spikes are 10 to 100 micron meters and oblique circular cone. It is important to clear the aerodynamic effect of the oblique circular cone. Artificial wing was fabricated by following processes. We fabricated micro spikes utilizing electro polishing. Fabricated micro spikes were set on plate utilizing micro spot bonding. We investigated the flow around the artificial wing and found that the flow around wing was controlled by micro spikes on wing. In this paper, we focused on comb shape of leading edge of wing. Comb shape is fabricated utilizing micro-EDM. We investigate flow characteristics of comb shape.

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13

Kim, Ki-Hoon, and Kyo-Nam Koo. "Design and Analysis of Section-divided Circular Composite Wing Spar." Journal of the Korean Society for Aeronautical & Space Sciences 47, no. 10 (October 31, 2019): 687–94. http://dx.doi.org/10.5139/jksas.2019.47.10.687.

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14

SAKAMOTO, Kasumi, Withun HEMSUWAN, and Tsutomu TAKAHASHI. "Influence of wing configuration on a circular cylinder blades wind turbine driven by longitudinal vortex." Proceedings of the National Symposium on Power and Energy Systems 2017.22 (2017): E131. http://dx.doi.org/10.1299/jsmepes.2017.22.e131.

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15

URSU, Stefan. "Development of dielectric elastomeric actuators for morphing wings." INCAS BULLETIN 13, no. 2 (June 4, 2021): 163–73. http://dx.doi.org/10.13111/2066-8201.2021.13.2.15.

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In the last decades, wing morphing structures have aroused great interest due to their capability to improve the aerodynamic efficiency of modern aircraft. DE actuators, also known as “artificial muscles” due to their ability to exhibit large actuation strains at high voltages, are suitable candidates for morphing applications. This paper focuses on the research and development of miniature dielectric elastomeric actuators for variable-thickness morphing wings. A conical elastomeric actuation configuration has been proposed, consisting of a VHB4910 dielectric membrane preloaded with a spring mechanism and constrained to a rigid circular ring. The mini-actuators are developed to be fixed in an actuation array, mounted to the wing skin. This new electromechanical actuation system is designed to be integrated on thin airfoil wings, where conventional morphing structures cannot be used, because of restricted mass and space requirements. By controlling the thickness distribution using the proposed actuators, we may be able to maintain and delay the location of the laminar-turbulent transit towards the trailing edge, promoting laminar flow over the wing surface. Experimental models and prototypes will be developed in the next phase of the research project for further investigations.

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16

Velicki, A., and P. Thrash. "Blended wing body structural concept development." Aeronautical Journal 114, no. 1158 (August 2010): 513–19. http://dx.doi.org/10.1017/s0001924000004000.

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Abstract A lightweight robust airframe design is one of the key technological advancements necessary for the successful launch of a blended wing body aircraft. The non-circular pressure cabin dictates that substantial improvements beyond current state-of-the-art aluminium and composite structures is needed, and that improvements of this magnitude will require radically new airframe design and manufacturing practices. Such an approach is described in this paper. It is a highly integrated structural concept that is tailored and optimised to fully exploit the orthotropic nature and unique processing advantages inherent in dry carbon fibres, while also employing stitching to enable a unique damage-arrest design approach.

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17

Rautenberg, Alexander, Martin Graf, Norman Wildmann, Andreas Platis, and Jens Bange. "Reviewing Wind Measurement Approaches for Fixed-Wing Unmanned Aircraft." Atmosphere 9, no. 11 (October 28, 2018): 422. http://dx.doi.org/10.3390/atmos9110422.

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One of the biggest challenges in probing the atmospheric boundary layer with small unmanned aerial vehicles is the turbulent 3D wind vector measurement. Several approaches have been developed to estimate the wind vector without using multi-hole flow probes. This study compares commonly used wind speed and direction estimation algorithms with the direct 3D wind vector measurement using multi-hole probes. This was done using the data of a fully equipped system and by applying several algorithms to the same data set. To cover as many aspects as possible, a wide range of meteorological conditions and common flight patterns were considered in this comparison. The results from the five-hole probe measurements were compared to the pitot tube algorithm, which only requires a pitot-static tube and a standard inertial navigation system measuring aircraft attitude (Euler angles), while the position is measured with global navigation satellite systems. Even less complex is the so-called no-flow-sensor algorithm, which only requires a global navigation satellite system to estimate wind speed and wind direction. These algorithms require temporal averaging. Two averaging periods were applied in order to see the influence and show the limitations of each algorithm. For a window of 4 min, both simplifications work well, especially with the pitot-static tube measurement. When reducing the averaging period to 1 min and thereby increasing the temporal resolution, it becomes evident that only circular flight patterns with full racetracks inside the averaging window are applicable for the no-flow-sensor algorithm and that the additional flow information from the pitot-static tube improves precision significantly.

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18

Mokry, Miroslav. "The Vortex Merger Factor in Aircraft Wake Turbulence." Aeronautical Journal 109, no. 1091 (January 2005): 1–13. http://dx.doi.org/10.1017/s0001924000000531.

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Abstract Vortex merger is studied within the context of two-dimensional discrete vortex sheets and demonstrated on two equally oriented circular vortices and aircraft tip and flap vortices. It is confirmed that, depending on the wing load distribution, the latter may or may not coalesce into a single counter-rotating pair. The interaction of a vortex with an equally oriented shear layer, governed by the same physical principle, suggests a possible intensification of an aircraft vortex in cross-wind shear.

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19

Khamseh, Hossein Bonyan, Luciano C. A. Pimenta, and Leonardo A. B. Tôrres. "Decentralized Coordination of Constrained Fixed-wing Unmanned Aerial Vehicles: Circular Orbits." IFAC Proceedings Volumes 47, no. 3 (2014): 1247–53. http://dx.doi.org/10.3182/20140824-6-za-1003.01643.

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20

Song, Sam Hong, and Cheol Woong Kim. "The Fatigue Crack and Delamination Behavior on the Fuselage-Wing Intersection Containing Variable Notches." International Journal of Modern Physics B 17, no. 08n09 (April 10, 2003): 1540–46. http://dx.doi.org/10.1142/s0217979203019290.

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The delamination and the fatigue crack propagation behavior in aramid fiber reinforced metal laminates(AFRMLs) containing a saw-cut and circular hole such as the fuselage-wing intersection was investigated. The fatigue crack propagation in aluminum layer is accompanied with the delamination between aluminum layer and fiber layer. The delamination deteriorates the fiber bridging mechanism in the crack tip of AFRMLs. Therefore, this study evaluates the stress distribution of AFRMLs containing a saw-cut and circular hole using the Average Stress Criterion (ASC) model. The delamination zone was observed by ultrasonic C-scan images. As the result of this study, in case of AFRMLs containing a saw-cut specimen. the fatigue crack propagation always occurred in aluminum layer and the delamination zone formed along the fatigue crack. However, in case of AFRMLs containing a circular hole specimen, the delamination zone was formed in two types. First, delamination zone was formed along the fatigue crack in aluminum layer. Second, delamination zone was formed without any fatigue crack around the circular hole. Consequently, delamination zone was formed dependently on the notch shape and the stress distribution.

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21

Stiros, Stathis C., Panos A. Psimoulis, and Christos L. Kolonas. "The theatre of Aitolian Makyneia." Annual of the British School at Athens 100 (November 2005): 299–313. http://dx.doi.org/10.1017/s0068245400021195.

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Remains of a recently excavated small theatre at the foot of a fortified hill, identified with Aitolian Makyneia, were studied on the basis of electronic surveying, CAD, graphical and analytical approximation techniques. This theatre, of the 4th or 3rd century BC, partly excavated on the hillside and built of large sandstone slabs, has an unusual shape, with its koilon consisting of a curvilinear wing of 14 rows of seats and an adjacent linear wing of three rows of blocks forming a single-row proedria. Geometric modelling of the theatre remains on the basis of graphical, and especially of analytical techniques, indicates that the circular wing of the koilon consists of equidistant, concentric rows of seats based on a design arc of 90° for the 1st row, with the corresponding chord normal to the linear wing. Possible poor remains of a skene were found oblique (81°) to the linear wing.

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22

YAMAMOTO, Yuzo. "Spanwise Optimum Normal Force Distribution of a Hemi-Circular Wing-in-Ground." TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 43, no. 142 (2001): 160–64. http://dx.doi.org/10.2322/tjsass.43.160.

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23

ISHIZUKA, Tomoyuki, Yasuaki KOHAMA, Takuma KATOH, and Satoshi KIKUCHI. "Wing in Ground Effect Characteristics of Circular-Arc Aerofoils for Aero-Train." Transactions of the Japan Society of Mechanical Engineers Series B 70, no. 693 (2004): 1179–85. http://dx.doi.org/10.1299/kikaib.70.1179.

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24

Kenyon, Kern E. "Lift on a Low Speed Circular Arc Wing due to Air Compression." Natural Science 13, no. 03 (2021): 88–90. http://dx.doi.org/10.4236/ns.2021.133008.

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25

FALCÃO, J. N., F. F. SALLES, and N. HAMADA. "The adults of Harpagobaetis Mol and Tomedontus Lugo-Ortiz and McCafferty (Ephemeroptera: Baetidae) with notes on the nymphal stage." Zootaxa 2530, no. 1 (July 8, 2010): 39. http://dx.doi.org/10.11646/zootaxa.2530.1.4.

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In the present study the imagos of Harpagobaetis Mol and Tomedontus Lugo-Ortiz & McCafferty are described for the first time. They can be differentiated from other genera of Baetidae by the following combination of characteristics: Harpagobaetis, forewing with paired marginal intercalary veins; hind wing present with two complete longitudinal veins; costal projection of hind wing pointed, placed in the basal third of anterior margin, cross veins absent; forceps three-segmented, segment I with bulbous base, segment III long, about 3 × as long as wide; Tomedontus, dorsal portion of turbinate eye circular; forewing with paired marginal intercalary veins; hind wing absent; forceps three-segmented, segment II with strong medial projection; subgenital plate without projection.

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26

De Laat, T. W. G., and R. Coene. "Two-dimensional vortex motion in the cross-flow of a wing-body configuration." Journal of Fluid Mechanics 305 (December 25, 1995): 93–109. http://dx.doi.org/10.1017/s0022112095004551.

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For a two-dimensional potential flow, Föppl obtained the equilibrium positions for a symmetric vortex pair behind a circular cylinder in a uniform oncoming flow. In this article it is shown that such an equilibrium is in general possible for a vortex in a stagnation flow (e. g. in a corner). Furthermore it is found that a vortex near such an equilibrium position will rotate with a definite frequency around this equilibrium. Expressions are derived for the frequencies associated with the closed orbits of the vortices in the case of equilibrium of a vortex in a stagnation flow and for the equilibrium of the symmetric vortex pair behind a circular cylinder in oncoming flow. For the large-amplitude case the vortex trajectories are claculated using a fifth-order Runge-Kutta integration method. The analysis is then extended to the case of a simple wing-body combination in a cross-flow such as arises for a slender aircraft at an angle of attack with vortices generated by strakes or at the front part of the body. At the wint-body junctions the motions of the vortices may be periodic, quasi-periodic or the vortices may be swept away, depending on the initial conditions.

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27

Singh, Nikhil Kumar, and Sikha Hota. "Three-dimensional waypoint following for fixed-wing unmanned aerial vehicles in obstacle-filled environments." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, no. 3 (September 24, 2019): 640–54. http://dx.doi.org/10.1177/0954410019877795.

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The paper computes optimal paths for fixed-wing unmanned aerial vehicles with bounded turn radii to follow a series of waypoints with specified directions in a three-dimensional obstacle-filled environment. In the existing literature, it was proved that the optimal path is of circular turn–straight line–circular turn (CSC) type for two consecutive waypoint configurations, when the points are sufficiently far apart and there is no obstacle in the field. The maximum of all minimum turn radii corresponding to all possible two-dimensional circular maneuvers was used for both the initial and final turns to develop the CSC-type paths. But, this paper considers the minimum turn radii for initial and final turns, corresponding to the maneuvering planes and which produces shorter CSC-type paths. In an obstacle-filled environment the shortest path may collide with obstacles, so a strategy is proposed to switch to the next best path that does not collide with obstacles. Using this technique, a series of waypoints is followed in the presence of obstacles of different types, for example, cylindrical, hemispherical, and spherical in shapes with different sizes. Finally, simulation results are presented to show the efficiency of the algorithm for obstacle avoidance. The computation time listed here indicates the potentiality of this algorithm for implementation in real time.

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28

YAMADA, Seiji, Shinsuke MOCHIZUKI, and Hironori YAMANE. "1826 An experimental study on the characteristics of wing for a small vertical-axis wind turbine : The characteristics of a circular arc wing with finite span." Proceedings of the JSME annual meeting 2008.2 (2008): 173–74. http://dx.doi.org/10.1299/jsmemecjo.2008.2.0_173.

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29

Guan, Zi Wu, and Yong Liang Yu. "Morphing Models of a Bat Wing in Flapping Flight." Applied Mechanics and Materials 461 (November 2013): 254–61. http://dx.doi.org/10.4028/www.scientific.net/amm.461.254.

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Kinematic models, which contain flapping and deformations, of a bat flapping wing when it flies at medium speeds are presented in the study. The deformations include cambering - morphing in the chordwise direction, bending - morphing in the spanwise direction and twisting respecting angles of attack (AOA) varying along the length of the wing. In the study, we assumed a circular-arc-shaped deformation when cambering or bending occurs, and introduced controlling parameters for each morphing. Then we showed the expressions of the controlling parameters varying with time at the bat flight speed of 3m/s according to the data provided by a literature, and verified the reasonability of the assumptions at last.

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30

BOERSMA, J. "NOTE ON THE LIFTING-SURFACE PROBLEM FOR A CIRCULAR WING IN INCOMPRESSIBLE FLOW." Quarterly Journal of Mechanics and Applied Mathematics 42, no. 1 (1989): 55–64. http://dx.doi.org/10.1093/qjmam/42.1.55.

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31

Shi, Lei, Wen Qiang Wang, Cheng Chun Zhang, Jing Wang, and Lu Quan Ren. "The Effect of Bionic V-Ring Surface on the Aerodynamic Noise of a Circular Cylinder." Applied Mechanics and Materials 461 (November 2013): 751–62. http://dx.doi.org/10.4028/www.scientific.net/amm.461.751.

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Inspired by stripe shaped structure of owl wing feathers, V-ring surface was proposed in this paper to reduce the aerodynamic noise of a circular cylinder. The effects of V-ring surface on the aerodynamic and aeroacoustic performance of the cylinder were investigated by wind tunnel and numerical simulation. We tested the fluctuating pressure of the smooth cylinder and the V-ring surface cylinder by pulsating pressure sensor in FD-09 wind tunnel of China Academy of Aerospace Aerodynamics（CAAA）. At a wind speed of 42m/s, the Reynolds number is 1.62×105based on the cylinder diameter D of 58mm. The test results showed that the overall fluctuating pressure on the measurement points of the V-ring surface cylinder was significantly decreased compared with the smooth cylinder. The mechanisms of aerodynamic noise control of circular cylinder by V-ring surface were studied by the Large Eddy Simulation（LES）and the Ffowcs Williams and Hawkings （FW-H） equation. The numerical simulation results showed that the aerodynamic noise of the V-ring surface cylinder was reduced by 4.1dB compared to the smooth cylinder. The sound pressure of V-ring surface cylinder model is reduced when the lift fluctuation becomes lower. The V-ring surface is capable of reducing the frequency of the vortex shedding and controlling the fluctuating lift force induced by unstable vortices acting on the cylinder surface.

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32

Saba, Matthias, Bodo D. Wilts, Johannes Hielscher, and Gerd E. Schröder-Turk. "Absence of Circular Polarisation in Reflections of Butterfly Wing Scales with Chiral Gyroid Structure." Materials Today: Proceedings 1 (2014): 193–208. http://dx.doi.org/10.1016/j.matpr.2014.09.023.

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33

Lakshminarayan, Vinod K., and James D. Baeder. "Improved Shroud Design for Rotary Wing MAV Applications Based on Computational Analysis." Journal of the American Helicopter Society 57, no. 4 (October 1, 2012): 1–5. http://dx.doi.org/10.4050/jahs.57.045001.

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A compressible Reynolds-averaged Navier–Stokes (RANS) solver is used to improve the design of a microscale shroud applicable for micro air vehicle (MAV) applications. The new shroud is primarily designed to improve the hover performance; however, it is also shaped to better suit nonhovering flight conditions. The proposed shroud design has an elliptic shape on the inner portion of the shroud inlet and a circular shape on the outer portion. A collective angle sweep study of the shrouded rotor configuration using the proposed shroud design shows significant performance benefits in hover.

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34

Pickhaver, T. W., and P. M. Render. "A technique to predict the aerodynamic effects of battle damage on an aircraft’s wing." Aeronautical Journal 119, no. 1218 (August 2015): 937–60. http://dx.doi.org/10.1017/s0001924000004267.

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Abstract A technique is developed that can be used to predict the effects of battle damage on the aerodynamic performance of an aircraft’s wing. The technique is based on results obtained from wind tunnel tests on a NASA LS(1)-0417MOD aerofoil with simulated gunfire damage. The wind tunnel model incorporated an internal cavity to represent typical aircraft construction and this was located between 24% and 75% of chord. The damage was simulated by circular holes with diameters between 20% and 40% of chord. To represent different attack directions, the inclination of the hole axis relative to the aerofoil chord was varied between ±60° pitch and 45° of roll. The aerofoil spanned the wind tunnel to create approximate two-dimensional conditions and balance measurements were carried out at a Reynolds number of 500,000 for incidences, increased in 2° increments, from –4° to 16°. Surface flow visualisation and pressure measurements were also carried out. For a given hole size, the increments in lift, drag and pitching moment coefficients produced trends when plotted against the difference between the upper and lower surface pressure coefficients on the undamaged aerofoil taken at the location of the damage. These trends are used as the basis of the predictive technique. The technique is used to predict the effects of a previously untested damage case, and these are compared with wind tunnel tests carried out on a half model finite aspect ratio wing. For all coefficients the trends in the predicted data are similar to experiment, although there are some discrepancies in absolute values. For the drag coefficient these discrepancies are partly accounted for by limitations in the technique, whilst discrepancies in the lift and pitching moment coefficients are attributed to limitations in the aerofoil test arrangements.

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35

Moyes, Alexander J., Pedro Paredes, Travis S. Kocian, and Helen L. Reed. "Secondary instability analysis of crossflow on a hypersonic yawed straight circular cone." Journal of Fluid Mechanics 812 (December 28, 2016): 370–97. http://dx.doi.org/10.1017/jfm.2016.793.

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The purpose of this paper is to provide secondary instability analysis of stationary crossflow vortices on a hypersonic yawed straight circular cone with a $7^{\circ }$ half-angle at $6^{\circ }$ angle of attack, free-stream Mach number 6 and unit Reynolds number $10.09\times 10^{6}~\text{m}^{-1}$. At an angle of attack, a three-dimensional boundary layer is developed between the windward and leeward symmetry planes. Under the action of azimuthal pressure gradients, the flow near the surface is deflected more than the flow near the edge of the boundary layer. This results in an inflectional velocity profile that can sustain the growth of crossflow vortices. The stationary crossflow instability is computed by means of the nonlinear parabolized stability equations, including a methodology to predict the stationary-crossflow marching path and variation of the spanwise number of waves in the marching direction solely from the basic state. Secondary instability analysis is performed using spatial BiGlobal equations based on two-dimensional partial differential equations. The secondary instabilities are calculated at different axial locations along two crossflow vortex trajectories selected to complement experiments conducted in the Mach 6 Quiet Tunnel at Texas A&M University and in the Boeing/AFOSR Mach 6 Quiet Tunnel at Purdue University. The secondary instability analysis captures various instability modes. Similar to observations in the low-speed regime for an infinite swept wing, secondary shear-layer instabilities are amplified as a consequence of the three-dimensional shear layer formed by crossflow vortices. Also, low-frequency travelling crossflow and high-frequency second modes coexist with the shear-layer instabilities. These results are shown to be in good agreement with the two sets of hypersonic yawed cone experiments (one with natural surface roughness and one with artificial discrete roughness) and compare well with experimental measurements of an incompressible swept wing.

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ARBAJ, KHAN DEMROT, SAKALLE RASHMI, and TIWARI NITIN. "TIME HISTORY ANALYSIS OF ELEVATED CIRCULAR TANK WHOSE COLUMN IS STIFFENED BY USING WING SLAB." i-manager's Journal on Structural Engineering 7, no. 2 (2018): 1. http://dx.doi.org/10.26634/jste.7.2.14485.

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Afzalimehr, Hossein, Somayeh Bakhshi, Jacques Gallichand, and Jueyi Sui. "Effect of vegetated-banks on local scour around a wing-wall abutment with circular edges." Journal of Hydrodynamics 26, no. 3 (June 2014): 447–57. http://dx.doi.org/10.1016/s1001-6058(14)60051-2.

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Gautam, Abhishek, Lokesh Pandey, and Satyendra Singh. "Influence of perforated triple wing vortex generator on a turbulent flow through a circular tube." Heat and Mass Transfer 54, no. 7 (February 3, 2018): 2009–21. http://dx.doi.org/10.1007/s00231-018-2296-4.

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Olejnik, Diana A., Bardienus P. Duisterhof, Matej Karásek, Kirk Y. W. Scheper, Tom van Dijk, and Guido C. H. E. de Croon. "A Tailless Flapping Wing MAV Performing Monocular Visual Servoing Tasks." Unmanned Systems 08, no. 04 (August 19, 2020): 287–94. http://dx.doi.org/10.1142/s2301385020500235.

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In the field of robotics, a major challenge is achieving high levels of autonomy with small vehicles that have limited mass and power budgets. The main motivation for designing such small vehicles is that compared to their larger counterparts, they have the potential to be safer, and hence be available and work together in large numbers. One of the key components in micro robotics is efficient software design to optimally utilize the computing power available. This paper describes the computer vision and control algorithms used to achieve autonomous flight with the [Formula: see text]30[Formula: see text]g tailless flapping wing robot, used to participate in the International Micro Air Vehicle Conference and Competition (IMAV 2018) indoor microair vehicle competition. Several tasks are discussed: line following, circular gate detection and fly through. The emphasis throughout this paper is on augmenting traditional techniques with the goal to make these methods work with limited computing power while obtaining robust behavior.

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Maricic, N. L. "Numerical estimation of aircrafts' unsteady lateral-directional stability derivatives." Theoretical and Applied Mechanics 33, no. 4 (2006): 311–37. http://dx.doi.org/10.2298/tam0604311m.

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A technique for predicting steady and oscillatory aerodynamic loads on general configuration has been developed. The prediction is based on the Doublet-Lattice Method, Slender Body Theory and Method of Images. The chord and span wise loading on lifting surfaces and longitudinal bodies (in horizontal and vertical plane) load distributions are determined. The configuration may be composed of an assemblage of lifting surfaces (with control surfaces) and bodies (with circular cross sections and a longitudinal variation of radius). Loadings predicted by this method are used to calculate (estimate) steady and unsteady (dynamic) lateral-directional stability derivatives. The short outline of the used methods is given in [1], [2], [3], [4] and [5]. Applying the described methodology software DERIV is developed. The obtained results from DERIV are compared to NASTRAN examples HA21B and HA21D from [4]. In the first example (HA21B), the jet transport wing (BAH wing) is steady rolling and lateral stability derivatives are determined. In the second example (HA21D), lateral-directional stability derivatives are calculated for forward- swept-wing (FSW) airplane in antisymmetric quasi-steady maneuvers. Acceptable agreement is achieved comparing the results from [4] and DERIV.

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Eiamsa-ard, Smith, and Khwanchit Wongcharee. "Experimental Study of TiO2-Water Nanofluid Flow in Corrugated Tubes Mounted with Semi-Circular Wing Tapes." Heat Transfer Engineering 39, no. 1 (January 12, 2017): 1–14. http://dx.doi.org/10.1080/01457632.2017.1280277.

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Nolan, Peter, Hunter McClelland, Craig Woolsey, and Shane Ross. "A Method for Detecting Atmospheric Lagrangian Coherent Structures Using a Single Fixed-Wing Unmanned Aircraft System." Sensors 19, no. 7 (April 3, 2019): 1607. http://dx.doi.org/10.3390/s19071607.

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The transport of material through the atmosphere is an issue with wide ranging implications for fields as diverse as agriculture, aviation, and human health. Due to the unsteady nature of the atmosphere, predicting how material will be transported via the Earth’s wind field is challenging. Lagrangian diagnostics, such as Lagrangian coherent structures (LCSs), have been used to discover the most significant regions of material collection or dispersion. However, Lagrangian diagnostics can be time-consuming to calculate and often rely on weather forecasts that may not be completely accurate. Recently, Eulerian diagnostics have been developed which can provide indications of LCS and have computational advantages over their Lagrangian counterparts. In this paper, a methodology is developed for estimating local Eulerian diagnostics from wind velocity data measured by a single fixed-wing unmanned aircraft system (UAS) flying in a circular arc. Using a simulation environment, driven by realistic atmospheric velocity data from the North American Mesoscale (NAM) model, it is shown that the Eulerian diagnostic estimates from UAS measurements approximate the true local Eulerian diagnostics and also predict the passage of LCSs. This methodology requires only a single flying UAS, making it easier and more affordable to implement in the field than existing alternatives, such as multiple UASs and Dopler LiDAR measurements. Our method is general enough to be applied to calculate the gradient of any scalar field.

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Kurz, Holger B. E., and Markus J. Kloker. "Receptivity of a swept-wing boundary layer to micron-sized discrete roughness elements." Journal of Fluid Mechanics 755 (August 14, 2014): 62–82. http://dx.doi.org/10.1017/jfm.2014.425.

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AbstractThe receptivity of a laminar swept-wing boundary layer to a spanwise array of circular roughness elements is investigated by means of direct numerical simulations (DNS). The initial amplitude of a steady crossflow mode generated by the shallow roughness elements does not vary strictly linearly with the roughness height, as often assumed. Rather, a fundamental, superlinear dependence of the receptivity amplitude on the roughness height is found. In order to account for shape effects, the roughness geometry is Fourier decomposed to its spanwise spectral content, and elements with a reduced spectrum are investigated. If only modes are present that synthesise a regular structure of alternating bumps and dimples of equal shape and size, the receptivity amplitude is strictly linear for each mode and nominal roughness heights up to at least 15 % of the local displacement thickness.

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Kuzmina, Kseniia, Ilia Marchevsky, Irina Soldatova, and Yulia Izmailova. "On the Scope of Lagrangian Vortex Methods for Two-Dimensional Flow Simulations and the POD Technique Application for Data Storing and Analyzing." Entropy 23, no. 1 (January 18, 2021): 118. http://dx.doi.org/10.3390/e23010118.

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The possibilities of applying the pure Lagrangian vortex methods of computational fluid dynamics to viscous incompressible flow simulations are considered in relation to various problem formulations. The modification of vortex methods—the Viscous Vortex Domain method—is used which is implemented in the VM2D code developed by the authors. Problems of flow simulation around airfoils with different shapes at various Reynolds numbers are considered: the Blasius problem, the flow around circular cylinders at different Reynolds numbers, the flow around a wing airfoil at the Reynolds numbers 104 and 105, the flow around two closely spaced circular cylinders and the flow around rectangular airfoils with a different chord to the thickness ratio. In addition, the problem of the internal flow modeling in the channel with a backward-facing step is considered. To store the results of the calculations, the POD technique is used, which, in addition, allows one to investigate the structure of the flow and obtain some additional information about the properties of flow regimes.

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Pani, B. S., and Lakshmanagouda G. Patil. "Discussion of “An Experimental Study on Turbulent Circular Wall Jets” by Adrian Wing-Keung Law and Herlina." Journal of Hydraulic Engineering 129, no. 9 (September 2003): 738–40. http://dx.doi.org/10.1061/(asce)0733-9429(2003)129:9(738).

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Wing-Keung Law, Adrian, and Herlina. "Closure to “An Experimental Study on Turbulent Circular Wall Jets” by Adrian Wing-Keung Law and Herlina." Journal of Hydraulic Engineering 129, no. 9 (September 2003): 740. http://dx.doi.org/10.1061/(asce)0733-9429(2003)129:9(740).

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Liu, Yan, Xin Su, Xiang Guo, Tao Suo, and Qifeng Yu. "A Novel Concentric Circular Coded Target, and Its Positioning and Identifying Method for Vision Measurement under Challenging Conditions." Sensors 21, no. 3 (January 28, 2021): 855. http://dx.doi.org/10.3390/s21030855.

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Coded targets have been demarcated as control points in various vision measurement tasks such as camera calibration, 3D reconstruction, pose estimation, etc. By employing coded targets, matching corresponding image points in multi images can be automatically realized which greatly improves the efficiency and accuracy of the measurement. Although the coded targets are well applied, particularly in the industrial vision system, the design of coded targets and its detection algorithms have encountered difficulties, especially under the conditions of poor illumination and flat viewing angle. This paper presents a novel concentric circular coded target (CCCT), and its positioning and identifying algorithms. The eccentricity error has been corrected based on a practical error-compensation model. Adaptive brightness adjustment has been employed to address the problems of poor illumination such as overexposure and underexposure. The robust recognition is realized by perspective correction based on four vertices of the background area in the CCCT local image. The simulation results indicate that the eccentricity errors of the larger and smaller circles at a large viewing angle of 70° are reduced by 95% and 77% after correction by the proposed method. The result of the wing deformation experiment demonstrates that the error of the vision method based on the corrected center is reduced by up to 18.54% compared with the vision method based on only the ellipse center when the wing is loaded with a weight of 6 kg. The proposed design is highly applicable, and its detection algorithms can achieve accurate positioning and robust identification even in challenging environments.

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Muslimov, Tagir Z., and Rustem A. Munasypov. "Multi-UAV cooperative target tracking via consensus-based guidance vector fields and fuzzy MRAC." Aircraft Engineering and Aerospace Technology 93, no. 7 (August 7, 2021): 1204–12. http://dx.doi.org/10.1108/aeat-02-2021-0058.

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Purpose This paper aims to propose a multi-agent approach to adaptive control of fixed-wing unmanned aerial vehicles (UAVs) tracking a moving ground target. The approach implies that the UAVs in a single group must maintain preset phase shift angles while rotating around the target so as to evaluate the target’s movement more accurately. Thus, the controls should ensure that the UAV swarm follows a moving circular path whose center is the target while also attaining and maintaining a circular formation of a specific geometric shape; and the formation control system is capable of self-tuning because the UAV dynamics is uncertain. Design/methodology/approach This paper considers two interaction architectures: an open-chain where each UAV only interacts with its neighbors; and a cooperative leader, where the leading UAV is involved in attaining the formation. The cooperative controllers are self-tuned by fuzzy model reference adaptive control (MRAC). Findings Using open-chain decentralized architecture allows to have an unlimited number of aircraft in a formation, which is in line with the swarm behavior concept. The approach was tested for efficiency and performance in various scenarios using complete nonlinear flying-wing UAV models equipped with configured standard autopilot models. Research limitations/implications Assume the target follows a rectilinear trajectory at a constant speed. The speed is supposed to be known in advance. Another assumption is that the weather is windless. Originality/value In contrast to known studies, this one uses Lyapunov guidance vector fields that are direction- and magnitude-nonuniform. The overall cooperative controller structure is based on a decentralized and centralized consensus.

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Monteiro, Antónia, Paul M. Brakefield, and Vernon French. "The Genetics and Development of an Eyespot Pattern in the Butterfly Bicyclus anynana: Response to Selection for Eyespot Shape." Genetics 146, no. 1 (May 1, 1997): 287–94. http://dx.doi.org/10.1093/genetics/146.1.287.

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The normally circular eyespots on the wing of the butterfly Bicyclus anynana were selected to become elliptical in two divergent lines, with antero-posterior elongation of the eyespots in one line and proximodistal elongation in the other. Selection was continued for nine generations, and symmetrical realized heritabilities of ∼15% were achieved initially. The elliptical eyespot shapes characteristic of each line were still produced when the signaling center of the eyespot (the focus) was surgically rotated by 90 or 180° or when an eyespot was induced ectopically by localized damage. We conclude that selection changed general properties of the epidermis that responds to signals emanating from the eyespot focus but did not affect the mechanism of focal signaling.

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Zhou, Yao-ming, Zhi-jun Meng, and Dao-chun Li. "Numerical computation of aerodynamic noise of two tandem circular cylinders and flapping wing motion based on immersed boundary method." Journal of Vibroengineering 18, no. 8 (December 31, 2016): 5572–87. http://dx.doi.org/10.21595/jve.2016.17188.

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