Artykuły w czasopismach: „Vertical tail”

1

PRISACARIU, Vasile, i Alexandru CHIRILĂ. "AERODINAMIC ANALYSIS OF HELICOPTER FENESTRON VERTICAL TAIL". SCIENTIFIC RESEARCH AND EDUCATION IN THE AIR FORCE 21, nr 1 (8.10.2019): 176–83. http://dx.doi.org/10.19062/2247-3173.2019.21.24.

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Schwaner, M. Janneke, Grace A. Freymiller, Rulon W. Clark i Craig P. McGowan. "How to Stick the Landing: Kangaroo Rats Use Their Tails to Reorient during Evasive Jumps Away from Predators". Integrative and Comparative Biology 61, nr 2 (3.05.2021): 442–54. http://dx.doi.org/10.1093/icb/icab043.

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Synopsis Tails are widespread in the animal world and play important roles in locomotor tasks, such as propulsion, maneuvering, stability, and manipulation of objects. Kangaroo rats, bipedal hopping rodents, use their tail for balancing during hopping, but the role of their tail during the vertical evasive escape jumps they perform when attacked by predators is yet to be determined. Because we observed kangaroo rats swinging their tails around their bodies while airborne following escape jumps, we hypothesized that kangaroo rats use their tails to not only stabilize their bodies while airborne, but also to perform aerial re-orientations. We collected video data from free-ranging desert kangaroo rats (Dipodomys deserti) performing escape jumps in response to a simulated predator attack and analyzed the rotation of their bodies and tails in the yaw plane (about the vertical-axis). Kangaroo rat escape responses were highly variable. The magnitude of body re-orientation in yaw was independent of jump height, jump distance, and aerial time. Kangaroo rats exhibited a stepwise re-orientation while airborne, in which slower turning periods corresponded with the tail center of mass being aligned close to the vertical rotation axis of the body. To examine the effect of tail motion on body re-orientation during a jump, we compared average rate of change in angular momentum. Rate of change in tail angular momentum was nearly proportional to that of the body, indicating that the tail reorients the body in the yaw plane during aerial escape leaps by kangaroo rats. Although kangaroo rats make dynamic 3D movements during their escape leaps, our data suggest that kangaroo rats use their tails to control orientation in the yaw plane. Additionally, we show that kangaroo rats rarely use their tail length at full potential in yaw, suggesting the importance of tail movement through multiple planes simultaneously.

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Wei, Ziyan, Jie Li, Songxiang Tang i Zhao Yang. "Investigation and Improvement of T-Tail Junction Flow Separation for a Demonstration Aircraft". Aerospace 9, nr 10 (29.09.2022): 567. http://dx.doi.org/10.3390/aerospace9100567.

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Flow separation is easily induced at the junctions of aircraft components, and for aircraft with T-type tails, in particular, it can lead to loss of directional stability under a small sideslip angle. In the reported study, improved delayed detached eddy simulation with a shear-layer-adapted length scale based on the k–ω shear-stress transport method was used to analyze and rectify the corner separation at the junctions of the horizontal and vertical parts of the tail of a demonstration aircraft. This was done to (i) suppress the flow separation caused by the complex interaction of the boundary layers on the horizontal and vertical tail parts at their junctions, and (ii) prevent the vertical tail parts from having any separated flow on their pressure and suction sides. The results showed that the main cause of the loss of directional stability was separation flow on the suction sides of the vertical tail parts. The corner flow separation was suppressed significantly by only using fairing cones at the junctions of the horizontal and vertical tail parts, thereby allowing the aircraft to maintain directional stability under a small sideslip angle.

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Luong, Quang Huan, Jeremy Jong, Yusuke Sugahara, Daisuke Matsuura i Yukio Takeda. "A Study on the Relationship between the Design of Aerotrain and Its Stability Based on a Three-Dimensional Dynamic Model". Robotics 9, nr 4 (19.11.2020): 96. http://dx.doi.org/10.3390/robotics9040096.

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A new generation electric high-speed train called Aerotrain has levitation wings and levitates under Wing-in-Ground (WIG) effect along a U-shaped guideway. The previous study found that lacking knowledge of the design makes the prototype unable to regain stability when losing control. In this paper, the nonlinear three-dimensional dynamic model of the Aerotrain based on the rigid body model has been developed to investigate the relationship between the vehicle body design and its stability. Based on the dynamic model, this paper considered an Aerotrain with a horizontal tail and a vertical tail. To evaluate the stability, the location and area of these tails were parameterized. The effects of these parameters on the longitudinal and directional stability have been investigated to show that: the horizontal tail gives its best performance if the tail area is a function of the tail location; the larger vertical tail area and (or) the farther vertical tail location will give better directional stability. As for the lateral stability, a dihedral front levitation wing design was investigated. This design did not show its effectiveness, therefore a control system is needed. The obtained results are useful for the optimization studies on Aerotrain design as well as developing experimental prototypes.

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Lee, B. H. K. "Vertical tail buffeting of fighter aircraft". Progress in Aerospace Sciences 36, nr 3-4 (kwiecień 2000): 193–279. http://dx.doi.org/10.1016/s0376-0421(00)00003-8.

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Cao, Xingyu, Hao Dong, Yunsong Gu, Keming Cheng i Fan Zhang. "Experimental Study of Vertical Tail Model Flow Control Based on Oscillating Jet". Applied Sciences 13, nr 2 (5.01.2023): 786. http://dx.doi.org/10.3390/app13020786.

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In this paper, wind tunnel experiments are conducted to study the control law and mechanism of oscillating jet flow control to improve the aerodynamic characteristics of the vertical tail when a civil aircraft encounters left side gust or significant crosswind during takeoff and landing. We measured the vertical tail scaling model’s aerodynamics, spatial flow field, and surface pressure when the Reynolds number was 2.12 × 105. The maximum momentum coefficient of the oscillating jet actuator reaches 0.332%. In addition, we studied the flow control effect of the three-dimensional vertical tail scaled model in different spanwise positions. The experimental results show that the oscillating jet at the rear edge of the stabilizer can significantly increase the lateral force of the vertical tail, and the increment of the lateral force can reach 36.5% under the worst condition of the negative side slip angle of the vertical tail. We can improve the lateral force coefficient of the vertical tail model by applying flow control alone at different spanwise locations. The wing root’s control effect and the vertical tail’s middle section are better than the wing tip’s. The oscillating jet can effectively restrain the flow separation on the rudder. In addition, the input of a high-energy jet “ejects” the mainstream, which increases the flow velocity at the side of the vertical tail actuator. It increases the circulation of the vertical tail. The oscillating jet flow control technology can effectively improve the vertical tail’s steering efficiency and increase the vertical tail’s lateral force, which is of great significance in improving the safety and economy of civil aircraft.

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Han, Bing, i Min Xu. "Prediction of Vertical Tail Buffet Using CFD/CSD Coupling Method". Mathematical Problems in Engineering 2021 (23.11.2021): 1–9. http://dx.doi.org/10.1155/2021/6295332.

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The vertical tail buffet induced by the vortex breakdown flow is numerically investigated. The unsteady flow is calculated by solving the RANS equations. The structural dynamic equations are decoupled in the modal coordinates. The radial basis functions (RBFs) are employed to generate the deformation mesh. The buffet response of the flexible tail is predicted by coupling the three sets of equations. The results show that the presence of asymmetry flow on the inner and outer surface of the tail forced the structural deflection offsetting the outboard. The frequency of the 2nd bending mode of the tail structure meets the peak frequency of the pressure fluctuation upon the tail surface, and the resonance phenomenon was observed. Therefore, the 2nd bending responses govern the flow field surrounding the vertical tail. Finally, the displacement of the vertical tail is small, while the acceleration with a large quantitation forces the vertical tail undergoing severe addition inertial loads.

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Yang, Qing, J. J. Li, Y. N. Yang i Z. Y. Ye. "Experimental and Computational Studies of Twin-Vertical-Tail Buffet". Advanced Materials Research 33-37 (marzec 2008): 1241–46. http://dx.doi.org/10.4028/www.scientific.net/amr.33-37.1241.

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Characteristics and mechanism of twin-vertical-tail buffet response on airplane configuration with wing root leading edge extension (LEX) were studied by both experiment and computation. Low-speed wind tunnel experiments were carried out to measure the root bending moment and tip acceleration of vertical tail. Vortical flow patterns were visualized via laser light sheet technique. Three-dimensional computation was performed to solve the unsteady Euler equations on rigid model. The results indicate that (1) bursting of vortices emanating from LEX is the main source of twin-vertical-tail buffet; (2) the Euler equations is able to predict the general characteristics of vertical-tail buffet response reasonably.

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Liu, Mingzhe, Can Cui i Jian Sun. "Preliminary Design of Aircraft without Vertical Tail". IOP Conference Series: Earth and Environmental Science 658 (20.02.2021): 012021. http://dx.doi.org/10.1088/1755-1315/658/1/012021.

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Andino, Marlyn Y., John C. Lin, Seele Roman, Emilio C. Graff, Mory Gharib, Edward A. Whalen i Israel J. Wygnanski. "Active Flow Control on Vertical Tail Models". AIAA Journal 57, nr 8 (sierpień 2019): 3322–38. http://dx.doi.org/10.2514/1.j057876.

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Nicolosi, Fabrizio, Danilo Ciliberti, Pierluigi Della Vecchia, Salvatore Corcione i Vincenzo Cusati. "A comprehensive review of vertical tail design". Aircraft Engineering and Aerospace Technology 89, nr 4 (3.07.2017): 547–57. http://dx.doi.org/10.1108/aeat-11-2016-0213.

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Purpose This work aims to deal with a comprehensive review of design methods for aircraft directional stability and vertical tail sizing. The focus on aircraft directional stability is due to the significant discrepancies that classical semi-empirical methods, as USAF DATCOM and ESDU, provide for some configurations because they are based on NACA wind tunnel (WT) tests about models not representative of an actual transport airplane. Design/methodology/approach The authors performed viscous numerical simulations to calculate the aerodynamic interference among aircraft parts on hundreds configurations of a generic regional turboprop aircraft, providing useful results that have been collected in a new vertical tail preliminary design method, named VeDSC. Findings The reviewed methods have been applied on a regional turboprop aircraft. The VeDSC method shows the closest agreement with numerical results. A WT test campaign involving more than 180 configurations has validated the numerical approach. Practical implications The investigation has covered both the linear and the non-linear range of the aerodynamic coefficients, including the mutual aerodynamic interference between the fuselage and the vertical stabilizer. Also, a preliminary investigation about rudder effectiveness, related to aircraft directional control, is presented. Originality/value In the final part of the paper, critical issues in vertical tail design are reviewed, highlighting the significance of a good estimation of aircraft directional stability and control derivatives.

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Wilga, C. D., i G. V. Lauder. "Function of the heterocercal tail in sharks: quantitative wake dynamics during steady horizontal swimming and vertical maneuvering". Journal of Experimental Biology 205, nr 16 (15.08.2002): 2365–74. http://dx.doi.org/10.1242/jeb.205.16.2365.

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SUMMARYThe function of the heterocercal tail in sharks has long been debated in the literature. Previous kinematic data have supported the classical theory which proposes that the beating of the heterocercal caudal fin during steady horizontal locomotion pushes posteroventrally on the water, generating a reactive force directed anterodorsally and causing rotation around the center of mass. An alternative model suggests that the heterocercal shark tail functions to direct reaction forces through the center of mass. In this paper,we quantify the function of the tail in two species of shark and compare shark tail function with previous hydrodynamic data on the heterocercal tail of sturgeon Acipenser transmontanus. To address the two models of shark heterocercal tail function, we applied the technique of digital particle image velocimetry (DPIV) to quantify the wake of two species of shark swimming in a flow tank. Both steady horizontal locomotion and vertical maneuvering were analyzed. We used DPIV with both horizontal and vertical light sheet orientations to quantify patterns of wake velocity and vorticity behind the heterocercal tail of leopard sharks (Triakis semifasciata) and bamboo sharks (Chiloscyllium punctatum) swimming at 1.0Ls-1, where L is total body length. Two synchronized high-speed video cameras allowed simultaneous measurement of shark body position and wake structure. We measured the orientation of tail vortices shed into the wake and the orientation of the central jet through the core of these vortices relative to body orientation. Analysis of flow geometry indicates that the tail of both leopard and bamboo shark generates strongly tilted vortex rings with a mean jet angle of approximately 30 ° below horizontal during steady horizontal swimming. The corresponding angle of the reaction force is much greater than body angle (mean 11 °) and the angle of the path of motion of the center of mass (mean approximately 0 °), thus strongly supporting the classical model of heterocercal tail function for steady horizontal locomotion. Vortex jet angle varies significantly with body angle changes during vertical maneuvering, but sharks show no evidence of active reorientation of jet angle relative to body angle, as was seen in a previous study on the function of sturgeon tail. Vortex jet orientation is significantly more inclined than the relatively horizontal jet generated by sturgeon tail vortex rings, demonstrating substantial differences in function in the heterocercal tails of sharks and sturgeon.We present a summary of forces on a swimming shark integrating data obtained here on the tail with previous data on pectoral fin and body function. Body orientation plays a critical role in the overall force balance and compensates for torques generated by the tail. The pectoral fins do not generate lift during steady horizontal locomotion, but play an important hydrodynamic role during vertical maneuvering.

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13

Deák, Péter. "Vertical tail FEA with a CAD/CAE based multidisciplinary process". Aircraft Engineering and Aerospace Technology 90, nr 4 (8.05.2018): 652–58. http://dx.doi.org/10.1108/aeat-11-2016-0212.

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Purpose The purpose of this paper is to make an analytical comparison of two vertical tail models from a structural point of view. Design/methodology/approach The original vertical tail design of PZL-106BT aircraft was used for Computer aided design (CAD) modeling and for creating the finite element model. Findings The nodal displacements, Von-Mises stresses and Buckling factors for two vertical tail models have been found using the finite element method. The idea of a possible Multidisciplinary concept assessment and design (MDCAD) concept was presented. Practical implications The used software analogy introduces an idea of having an automated calculation procedure within the framework of MDCAD. Originality/value The aircraft used for calculation had undergone a modification in its vertical tail length, as there was an urgent need to calculate for the plane’s manufacturer, PZL Warszawa – Okecie.

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SCHOLZ, Dieter. "Empennage sizing with the tail volume complemented with a method for dorsal fin layout". INCAS BULLETIN 13, nr 3 (4.09.2021): 149–64. http://dx.doi.org/10.13111/2066-8201.2021.13.3.13.

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Purpose: Provide good values for the tail volume coefficient and the lever arm as a percentage of the fuselage length. Provide a statistical method for dorsal fin layout. – Methodology: Based on an understanding of flight physics, the statistical correlation of real aircraft parameters is investigated. This is based on the firm conviction that high fidelity parameters for future aircraft need a checked against parameters of existing successful aircraft. – Findings: Typical tail volume coefficients are between 0.5 and 1.0 for the horizontal tail and between 0.03 and 0.08 for the vertical tail depending on aircraft category. Empennage statistics have clear trends. The often weak correlation shows that aircraft design allows for sufficient designer's choice. Only a minority of aircraft feature a dorsal fin. Designers see it as an added surface rather than as part of the vertical tail. It is used to limit the hypothetical risk of vertical tail stall due to high sideslip angles. – Research Limitations: Results obtained from statistics are close to reality, but not a proof to fulfill requirements. – Practical Implications: Methods from the paper can be used for quick initial sizing of a vertical tail with or without dorsal fin or sizing of a horizontal tail. These results can also be used as good starting values for optimization tools in aircraft design. – Originality: Estimation of the tail lever arm is necessary for sizing with the tail volume coefficient, but had not been investigated to any detail. A method for the layout of dorsal fins was missing.

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Sheta, E. F., i L. J. Huttsell. "Characteristics of F/A-18 vertical tail buffeting". Journal of Fluids and Structures 17, nr 3 (marzec 2003): 461–77. http://dx.doi.org/10.1016/s0889-9746(02)00138-x.

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Liu, Yaolong, i Tianhong Jiang. "Conceptual Aircraft Empennage Design Based on Multidisciplinary Design Optimization Approach". International Journal of Aerospace Engineering 2022 (18.10.2022): 1–9. http://dx.doi.org/10.1155/2022/9288966.

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Within a conventional aircraft design process, the horizontal tail and vertical tail are generally sized via volume coefficient methods. In this manuscript, an improved method for conceptual aircraft tail design based on multidisciplinary design optimization (MDO) approach with stability and control constraints has been developed. To develop this method, first, the tail design requirements have been derived from the regulations and the fundamental functionalities of tail plans. Then, the empennage design is formulated as an MDO problem. Eventually the design optimization of horizontal and vertical tail is combined with the design optimization of the aircraft wing. A test case is presented for concurrent wing and tail plane design, which resulted in more than 9% reduction in aircraft block fuel weight and more than 3% reduction in aircraft maximal takeoff weight, which indicates a great potential for fuel burn and carbon reductions with empennage design optimization at conceptual aircraft design phase.

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Hauch, R. M., J. H. Jacobs, C. Dima i K. Ravindra. "Reduction of vertical tail buffet response using active control". Journal of Aircraft 33, nr 3 (maj 1996): 617–22. http://dx.doi.org/10.2514/3.46990.

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Yang Guang, 杨. 光., 刘欢欢 Liu Huanhuan, 周佳平 Zhou Jiaping, 钦兰云 Qin Lanyun, 王. 维. Wang Wei i 任宇航 Ren Yuhang. "Research on laser deposition repair aircraft vertical tail beam". Infrared and Laser Engineering 46, nr 2 (2017): 206004. http://dx.doi.org/10.3788/irla201746.0206004.

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Yang Guang, 杨. 光., 刘欢欢 Liu Huanhuan, 周佳平 Zhou Jiaping, 钦兰云 Qin Lanyun, 王. 维. Wang Wei i 任宇航 Ren Yuhang. "Research on laser deposition repair aircraft vertical tail beam". Infrared and Laser Engineering 46, nr 2 (2017): 206004. http://dx.doi.org/10.3788/irla20174602.206004.

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Zhao, Y. H., i H. Y. Hu. "Active Control of Vertical Tail Buffeting by Piezoelectric Actuators". Journal of Aircraft 46, nr 4 (lipiec 2009): 1167–75. http://dx.doi.org/10.2514/1.39464.

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Sachs, G. "Why Birds and Miniscale Airplanes Need No Vertical Tail". Journal of Aircraft 44, nr 4 (lipiec 2007): 1159–67. http://dx.doi.org/10.2514/1.20175.

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Vinayagamurthy, G., K. M. Parammasivam i S. Nadaraja Pillai. "Flutter Analysis of Wing, Booster Fin and Vertical Tail". Applied Mechanics and Materials 110-116 (październik 2011): 3500–3505. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.3500.

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Aerospace vehicles are subjected to various types of severe environmental loads. The basic design criterion includes the minimum weight configuration that results in very flexible structures, which leads to various types of structural interaction problems like flutter, divergence etc. Hence every aerospace vehicle should be analysed for its aeroelastic instabilities. In the present work the flutter analysis of a typical space vehicle was carried out in substructure level with the interface fixed condition. The doublet lattice, zona51 and piston theories are used in the unsteady aerodynamic calculations for the subsonic, supersonic and hypersonic speed regimes. As there is no theoretical procedure for transonic speeds, doublet lattice method has been used in the present analysis. Frequency and damping versus velocity are presented to identify the flutter velocities and the flutter behavior.

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Katsurayama, Yuta, Mingcong Deng i Changan Jiang. "Operator-based experimental studies on nonlinear vibration control for an aircraft vertical tail with considering low-order modes". Transactions of the Institute of Measurement and Control 38, nr 12 (22.07.2016): 1421–33. http://dx.doi.org/10.1177/0142331215592063.

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In this paper, a robust nonlinear control design using an operator-based robust right coprime factorization approach is considered for vibration control on an aircraft vertical tail with piezoelectric elements. First, a model of the aircraft vertical tail is derived to describe vibration response using the operator-based approach, where, to stabilize vibration of the tail, piezoelectric elements are used as actuators and a hysteresis nonlinear property of piezoelectric actuators is considered. Simultaneously, positions of the piezoelectric actuators that are stuck on the plate are arranged by using a finite element method. Then based on the obtained operator-based model, a robust nonlinear feedback control design is given by using robust right coprime factorization for the aircraft vertical tail with considering the effect of hysteresis nonlinearity from piezoelectric actuators. In particular, low-order modes are employed to design the control scheme even though vibration is configured by high-order modes. In other words, robustness is considered, and the desired performance of tracking is discussed. Finally, both simulation and experimental results are shown to verify the effectiveness of the proposed control scheme.

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Liao, J., i G. V. Lauder. "Function of the heterocercal tail in white sturgeon: flow visualization during steady swimming and vertical maneuvering". Journal of Experimental Biology 203, nr 23 (1.12.2000): 3585–94. http://dx.doi.org/10.1242/jeb.203.23.3585.

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Basal ray-finned fishes possess a heterocercal tail in which the dorsal lobe containing the extension of the vertebral column is longer than the ventral lobe. Clarifying the function of the heterocercal tail has proved elusive because of the difficulty of measuring the direction of force produced relative to body position in the aquatic medium. We measured the direction of force produced by the heterocercal tail of the white sturgeon (Acipenser transmontanus) by visualizing flow in the wake of the tail using digital particle image velocimetry (DPIV) while simultaneously recording body position and motion using high-speed video. To quantify tail function, we measured the vertical body velocity, the body angle and the path angle of the body from video recordings and the vortex ring axis angle and vortex jet angle from DPIV recordings of the wake downstream from the tail. These variables were measured for sturgeon exhibiting three swimming behaviors at 1.2 L s(−)(1), where L is total body length: rising through the water column, holding vertical position, and sinking through the water column. For vertical body velocity, body angle and path angle values, all behaviors were significantly different from one another. For vortex ring axis angle and vortex jet angle, rising and holding behavior were not significantly different from each other, but both were significantly different from sinking behavior. During steady horizontal swimming, the sturgeon tail generates a lift force relative to the path of motion but no rotational moment because the reaction force passes through the center of mass. For a rising sturgeon, the tail does not produce a lift force but causes the tail to rotate ventrally in relation to the head since the reaction force passes ventral to the center of mass. While sinking, the direction of the fluid jet produced by the tail relative to the path of motion causes a lift force to be created and causes the tail to rotate dorsally in relation to the head since the reaction force passes dorsal to the center of mass. These data provide evidence that sturgeon can actively control the direction of force produced by their tail while maneuvering through the water column because the relationship between vortex jet angle and body angle is not constant.

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Yue Lee, Francis Chun, Christian Jenssen i Christoph F. Dietrich. "A common misunderstanding in lung ultrasound: the comet tail artefact". Medical Ultrasonography 20, nr 3 (30.08.2018): 379. http://dx.doi.org/10.11152/mu-1573.

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The comet tail artefact is probably one of the most commonly and imprecisely used to describe vertical artefacts found in lung ultrasound. Two distinct artefacts are commonly observed: the lung comets and the B-lines. Both artefacts differ with regard to generation mechanism and clinical significance. This review explores the current understanding and use of these two artefacts in lung ultrasound and suggests how to avoid the pitfalls related to confusing comet tail artefacts with other vertical artefacts.

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Zhang, Xiao Ping, Rui Ren i Hui Ping Kang. "Study on Unsteady Deformation Law in Roughing Stage of Continuous Hot Strip Rolling". Applied Mechanics and Materials 595 (lipiec 2014): 45–50. http://dx.doi.org/10.4028/www.scientific.net/amm.595.45.

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The vertical-horizontal rolling in roughing stage of continuous hot strip rolling is a common production technique of controlling slab width effectively. Vertical rolling will induce dog-bone, width loss and fish tail in unsteady deformation zone of slab head and tail. A 3D elastic-plastic FEM model for roughing stage of continuous hot strip rolling was established using ABAQUS/Explicit and research on the influences of those technical parameters such as slab width, slab thickness, reduction of vertical roll and horizontal roll on unsteady deformation of metal was carried out. The research work provides a scientific basis for the optimization of roughing rolling technical schedule.

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Chen, Y., V. Wickramasinghe i D. Zimcik. "Active Control of a hybrid actuation system for aircraft vertical fin buffet load alleviation". Aeronautical Journal 110, nr 1107 (maj 2006): 315–26. http://dx.doi.org/10.1017/s000192400001318x.

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AbstractTwin-tail fighter aircraft may experience intense buffet loads when flying at high angles of attack. One such aircraft is the F/A-18 where the broadband buffet loads primarily excite the first bending and torsional modes of the vertical fin, resulting in significant vibration and dynamic stresses on the vertical tail structure. This buffet phenomenon reduces the fatigue life of the aircraft structure while decreasing mission availability.An international technical co-operation program was initiated to develop a novel hybrid actuation system to actively alleviate the buffet response of a full-scale F/A-18 vertical fin. A hydraulic rudder actuator was used to control the bending mode of the vertical fin using rudder inertia forces. Multiple macro fiber composite actuators were distributed optimally to provide maximum induced strain control authority for the torsional mode. In order to develop an effective control law, a system identification approach was conducted to obtain a state-space model of the vertical fin using open-loop test data. An LQG control law was selected to minimise the dynamic response of the vertical fin at critical locations. The effectiveness of the control law was verified through extensive simulation prior to closed-loop experiments. The LQG control law demonstrated high robustness in all excitation load conditions; both bending and torsional vibration modes of the vertical tail were suppressed effectively and simultaneously. The dynamic stress and acceleration response at critical locations were also reduced significantly. A closed-loop experiment was conducted on a full-scale F/A-18 empennage using the IFOSTP test rig, and the experimental results verified the effectiveness of the control law development methodology used for the full-scale hybrid buffet load system for the F/A-18 aircraft. In addition, the ground vibration test demonstrated that the hybrid actuation system is a feasible solution to alleviate the vertical tail buffet loads in high performance fighter aircraft.

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Wu, Bin, Peng Chen, Yong Jiang Hu i Chang Long Wang. "Research on Attitude Singularity Problem of Small Tail-Sitter Aircraft". Applied Mechanics and Materials 599-601 (sierpień 2014): 401–4. http://dx.doi.org/10.4028/www.scientific.net/amm.599-601.401.

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Singularity problem in attitude estimation of small tail-sitter aircraft with traditional algorithm is researched. According to the flight characteristics of small tail-sitter aircraft, a new algorithm is proposed. Vertical Euler angles whose singularity points are away from standard Euler angles are introduced. Only one set of angles are used in horizontal or near-vertical state to avoid singularity. Simulation results show that attitude angles can vary continuously and have high accuracy under the condition of a large tilting angle.

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Chiu, Chyn-Shan, i I. J. Lin. "Sidewash on the vertical tail in subsonic and supersonic flows". Journal of Aircraft 31, nr 6 (listopad 1994): 1252–56. http://dx.doi.org/10.2514/3.46643.

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Whalen, Edward A., Arvin Shmilovich, Marc Spoor, John Tran, Paul Vijgen, John C. Lin i Marlyn Andino. "Flight Test of an Active Flow Control Enhanced Vertical Tail". AIAA Journal 56, nr 9 (wrzesień 2018): 3393–98. http://dx.doi.org/10.2514/1.j056959.

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Dandois, Julien, Christophe Verbeke i Frédéric Ternoy. "Performance Enhancement of a Vertical Tail Model with Sweeping Jets". AIAA Journal 58, nr 12 (grudzień 2020): 5202–15. http://dx.doi.org/10.2514/1.j059161.

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32

Kim, David, i Maciej Marciniak. "Prediction of Vertical Tail Maneuver Loads Using Backpropagation Neural Networks". Journal of Aircraft 37, nr 3 (maj 2000): 526–30. http://dx.doi.org/10.2514/2.2630.

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33

Sheta, Essam F. "Alleviation of Vertical Tail Buffeting of F/A-18 Aircraft". Journal of Aircraft 41, nr 2 (marzec 2004): 322–30. http://dx.doi.org/10.2514/1.9327.

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34

Rathay, Nicholas W., Matthew J. Boucher, Michael Amitay i Edward Whalen. "Performance Enhancement of a Vertical Tail Using Synthetic Jet Actuators". AIAA Journal 52, nr 4 (kwiecień 2014): 810–20. http://dx.doi.org/10.2514/1.j052645.

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35

Petrukovich, A. A., i Y. I. Yermolaev. "Interball-tail observations of vertical plasma motions in the magnetotail". Annales Geophysicae 20, nr 3 (31.03.2002): 321–27. http://dx.doi.org/10.5194/angeo-20-321-2002.

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Abstract. The Interball spacecraft configuration favors, in contrast to previous experiments, investigation of vertical ion flows (GSM Vz ). We use measurements of the CORALL instrument for the statistical study of Vz and Vy plasma flows in the mid-tail plasma sheet. In agreement with the previous observations, the mean Vy was positive on the dusk side and negative on the dawn side. When IMF was southward, the mean Vz consisted of the convection flow towards the equatorial plane ~ 7 km/s and the northward flow ~ 8 km/s. When IMF was northward, both components nearly vanished. The velocity variance was much larger than the mean values. The Vz variance maximized on the dawn flank and was always 15–20% smaller than the Vy one. The Vy variance maximized in the pre-midnight sector closer to the neutral sheet. We conclude that velocity fluctuations are composed with the inherent high-beta plasma turbulence contributing to all components, and the BBF-related activity contributing mainly to Vy in the pre-midnight plasma sheet.Key words. Magnetospheric physics (magnetotail; plasma sheet; plasma convection)

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36

Lintner, Benjamin R., Christopher E. Holloway i J. David Neelin. "Column Water Vapor Statistics and Their Relationship to Deep Convection, Vertical and Horizontal Circulation, and Moisture Structure at Nauru". Journal of Climate 24, nr 20 (15.10.2011): 5454–66. http://dx.doi.org/10.1175/jcli-d-10-05015.1.

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Abstract Relationships among relatively high-frequency probability distribution functions (pdfs) of anomalous column water vapor (cwv), precipitating deep convection, and the vertical and horizontal structures of circulation and tropospheric moisture are investigated for the Atmospheric Radiation Measurement (ARM) climate observing facility at Nauru in the western equatorial Pacific. At the highest frequencies (subdaily) analyzed, the cwv pdf exhibits a Gaussian core with pronounced longer-than-Gaussian, approximately exponential tails, with the relatively lower-frequency submonthly pdfs becoming more Gaussian distributed across the entire range of cwv variability. The genesis and morphology of the longer-than-Gaussian tails are examined within the context of several hypothetical mechanisms outlined in prior work. For example, pdf conditioning on ARM optical gauge precipitation measurements reveals an association of the positive-side tail with precipitating deep convective conditions; thus, despite the condensation and fallout of cwv during rainfall events, it is argued that updraft vertical motions associated with deep convection locally compensate the loss by increasing cwv. Using vertical moisture profiles from ARM radiosonde measurements, vertical structures of specific humidity anomalies associated with tail-regime cwv excursions are computed, with the negative cwv profile significantly departing from the mean profile in the lower free troposphere. Such behavior is consistent with local restorative surface evaporative forcing and turbulent mixing in the atmospheric boundary layer and drying of the column from above during descent conditions. Analysis of cwv variability with respect to the horizontal moisture structure, using gridded measurements from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) and trajectories from the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model driven by NCEP–NCAR reanalysis meteorology underscores how the horizontal and vertical components modulate Nauru cwv: in particular, high cwv conditions at Nauru are often associated with weakened low-level inflow from the dry regions to the east of Nauru and stronger along-trajectory ascent. Finally, comparison of the ARM-based pdfs to those estimated from the reanalysis illustrates how pdf-based diagnostics may be useful tools for model intercomparison and validation.

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37

Paziresh, Ali, Amir Hossein Nikseresht i Hashem Moradi. "Wing-Body and Vertical Tail Interference Effects on Downwash Rate of the Horizontal Tail in Subsonic Flow". Journal of Aerospace Engineering 30, nr 4 (lipiec 2017): 04017001. http://dx.doi.org/10.1061/(asce)as.1943-5525.0000704.

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38

Schäfer, Dominik. "T-tail flutter simulations with regard to quadratic mode shape components". CEAS Aeronautical Journal 12, nr 3 (18.06.2021): 621–32. http://dx.doi.org/10.1007/s13272-021-00524-8.

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AbstractIt is known that the dynamic aeroelastic stability of T-tails is dependent on the steady aerodynamic forces at aircraft trim condition. Accounting for this dependency in the flutter solution process involves correction methods for doublet lattice method (DLM) unsteady aerodynamics, enhanced DLM algorithms, unsteady vortex lattice methods (UVLM), or the use of CFD. However, the aerodynamic improvements along with a commonly applied modal approach with linear displacements results in spurious stiffness terms, which distort the flutter velocity prediction. Hence, a higher order structural approach with quadratic mode shape components is required for accurate flutter velocity prediction of T-tails. For the study of the effects of quadratic mode shape components on T-tail flutter, a generic tail configuration without sweep and taper is used. Euler based CFD simulations are applied involving a linearized frequency domain (LFD) approach to determine the generalized aerodynamic forces. These forces are obtained based on steady CFD computations at varying horizontal tail plane (HTP) incidence angles. The quadratic mode shape components of the fundamental structural modes for the vertical tail plane (VTP), i.e., out-of-plane bending and torsion, are received from nonlinear as well as linear finite element analyses. Modal coupling resulting solely from the extended modal representation of the structure and its influence on T-tail flutter is studied. The g-method is applied to solve for the flutter velocities and corresponding flutter mode shapes. The impact of the quadratic mode shape components is visualized in terms of flutter velocities in dependency of the HTP incidence angle and the static aerodynamic HTP loading.

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39

Chen, Sinuo, Zhiwei Shi, Zijie Zhao, Xi Geng i Zhen Chen. "Investigation of vertical tail buffeting alleviation controlled by nanosecond plasma actuators". Physics of Fluids 33, nr 8 (sierpień 2021): 087109. http://dx.doi.org/10.1063/5.0057280.

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40

Bramesfeld, Götz, Mark D. Maughmer i Steven M. Willits. "Piloting Strategies for Controlling a Transport Aircraft After Vertical-Tail Loss". Journal of Aircraft 43, nr 1 (styczeń 2006): 216–25. http://dx.doi.org/10.2514/1.13357.

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41

Zhang, Qing, i Zheng-yin Ye. "Novel Method Based on Inflatable Bump for Vertical Tail Buffeting Suppression". Journal of Aircraft 52, nr 1 (styczeń 2015): 367–71. http://dx.doi.org/10.2514/1.c032552.

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42

Hazra, Rajat Subhra, i Krishanu Maulik. "Tail Behavior of Randomly Weighted Sums". Advances in Applied Probability 44, nr 3 (wrzesień 2012): 794–814. http://dx.doi.org/10.1239/aap/1346955265.

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Let {Xt, t ≥ 1} be a sequence of identically distributed and pairwise asymptotically independent random variables with regularly varying tails, and let {Θt, t ≥ 1} be a sequence of positive random variables independent of the sequence {Xt, t ≥ 1}. We will discuss the tail probabilities and almost-sure convergence of X(∞) = ∑t=1∞ΘtXt+ (where X+ = max{0, X}) and max1≤k<∞∑t=1kΘtXt, and provide some sufficient conditions motivated by Denisov and Zwart (2007) as alternatives to the usual moment conditions. In particular, we illustrate how the conditions on the slowly varying function involved in the tail probability of X1 help to control the tail behavior of the randomly weighted sums. Note that, the above results allow us to choose X1, X2,… as independent and identically distributed positive random variables. If X1 has a regularly varying tail of index -α, where α > 0, and if {Θt, t ≥ 1} is a positive sequence of random variables independent of {Xt}, then it is known – which can also be obtained from the sufficient conditions in this article – that, under some appropriate moment conditions on {Θt, t ≥ 1}, X(∞) = ∑t=1∞ΘtXt converges with probability 1 and has a regularly varying tail of index -α. Motivated by the converse problems in Jacobsen, Mikosch, Rosiński and Samorodnitsky (2009) we ask the question: if X(∞) has a regularly varying tail then does X1 have a regularly varying tail under some appropriate conditions? We obtain appropriate sufficient moment conditions, including the nonvanishing Mellin transform of ∑t=1∞Θt along some vertical line in the complex plane, so that the above is true. We also show that the condition on the Mellin transform cannot be dropped.

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43

Hazra, Rajat Subhra, i Krishanu Maulik. "Tail Behavior of Randomly Weighted Sums". Advances in Applied Probability 44, nr 03 (wrzesień 2012): 794–814. http://dx.doi.org/10.1017/s0001867800005887.

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Let {X t , t ≥ 1} be a sequence of identically distributed and pairwise asymptotically independent random variables with regularly varying tails, and let {Θ t , t ≥ 1} be a sequence of positive random variables independent of the sequence {X t , t ≥ 1}. We will discuss the tail probabilities and almost-sure convergence of X (∞) = ∑ t=1 ∞Θ t X t + (where X + = max{0, X}) and max1≤k<∞∑ t=1 k Θ t X t , and provide some sufficient conditions motivated by Denisov and Zwart (2007) as alternatives to the usual moment conditions. In particular, we illustrate how the conditions on the slowly varying function involved in the tail probability of X 1 help to control the tail behavior of the randomly weighted sums. Note that, the above results allow us to choose X 1, X 2,… as independent and identically distributed positive random variables. If X 1 has a regularly varying tail of index -α, where α > 0, and if {Θ t , t ≥ 1} is a positive sequence of random variables independent of {X t }, then it is known – which can also be obtained from the sufficient conditions in this article – that, under some appropriate moment conditions on {Θ t , t ≥ 1}, X (∞) = ∑ t=1 ∞Θ t X t converges with probability 1 and has a regularly varying tail of index -α. Motivated by the converse problems in Jacobsen, Mikosch, Rosiński and Samorodnitsky (2009) we ask the question: if X (∞) has a regularly varying tail then does X 1 have a regularly varying tail under some appropriate conditions? We obtain appropriate sufficient moment conditions, including the nonvanishing Mellin transform of ∑ t=1 ∞Θ t along some vertical line in the complex plane, so that the above is true. We also show that the condition on the Mellin transform cannot be dropped.

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44

Wang, Chia-Chi, Chia Chou i Wei-Liang Lee. "Breakdown and Reformation of the Intertropical Convergence Zone in a Moist Atmosphere". Journal of the Atmospheric Sciences 67, nr 4 (1.04.2010): 1247–60. http://dx.doi.org/10.1175/2009jas3164.1.

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Abstract The effects of moisture on the intertropical convergence zone (ITCZ) over the eastern Pacific on the synoptic time scale are investigated using an intermediate complexity atmospheric circulation model, the quasi-equilibrium tropical circulation model (QTCM1), on an aquaplanet. The dry simulation shows results consistent with those of simple dynamic models, except that a slightly stronger heating rate is needed owing to different model designs. In the moist simulations, the most important result is the formation of a tail southwest of a vortex during and after the ITCZ breakdown. This tail may extend zonally more than 60° longitude and last for more than two weeks in an idealized simulation. In the eastern North Pacific, this phenomenon is often observed in cases that involve easterly waves. In a sense, the formation of the tail suggests a possible mechanism that forms an ITCZ efficiently. This study shows that the surface convergent flow induced by a disturbance initializes a positive wind–evaporation feedback that forms the tail. In the tail, the most important energy source is surface evaporation, and the latent heat is nicely balanced by an adiabatic cooling of the ascending motion. In other words, the energy is redistributed vertically by vertical energy convergence. The lifespan of the tail is controlled by the propagation of tropical waves that modify the surface wind pattern, leading to a decrease in surface wind speed and corresponding surface fluxes. It may explain the absence of the tail in some of the events in the real atmosphere.

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45

Coombs Jr., Walter P. "Ankylosaurian tail clubs of middle Campanian to early Maastrichtian age from western North America, with description of a tiny club from Alberta and discussion of tail orientation and tail club function". Canadian Journal of Earth Sciences 32, nr 7 (1.07.1995): 902–12. http://dx.doi.org/10.1139/e95-075.

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There are numerous undescribed tail clubs of diverse morphologies that may be assigned to Euoplocephalus (Ornithischia, Thyreophora, Ankylosauridae) of middle Campanian to early Maastrichtian age. Among these is an exceptionally small club, the smallest so far described from North America. Most, but not all, clubs can be placed into one of three shape categories: round, bluntly pointed, or elongate. Much of this diversity is ontogenetic or individual, but some of it may be taxonomic. Caudal structure restricts lateral, and especially vertical, tail flexibility. Analysis of hindlimb length, tail length, and downward angle of the tail from the hips suggests that the tail was normally carried and swung just above the ground, and was used primarily defensively, for striking at the metatarsals of an attacking theropod. Intraspecific, agonistic functions are possible, but improbable.

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46

Wang, Xiaoming, i Shengguo Liang. "Maneuverability Analysis of a Novel Portable Modular AUV". Mathematical Problems in Engineering 2019 (26.06.2019): 1–17. http://dx.doi.org/10.1155/2019/1631930.

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ZFAUV is a novel portable modular AUV. There are four fixed thrusters at tail, and two tunnel thrusters are set at front. The maneuverability of ZFAUV is relatively high. It can turn around in situ, move lateral or move up/down vertical. The yaw and pitch can be controlled by tunnel thrusters or differential control of tail thrusters, but differential control will reduce the forward force. Different from propeller-rudder AUVs, the turning radius is related to speed forward: the smaller the speed forward, the smaller the turning radius. The minimum turning radius tends to be zero. The mathematical model is built first; then CFD is used to predict the thrust and torque of tail thrusters and tunnel thrusters. Through numerical simulation, zigzag maneuver analysis in horizontal plane, and trapezoidal steering maneuver analysis in vertical plane, the maneuverability of ZFAUV is obtained. The maneuverability of ZFAUV becomes worse with the increase of speed. The maneuverability of differential control is better than that of tunnel control. In the case of specific thrust distribution of tail thrusters and tunnel thrusters, ZFAUV can turn around in situ (the maximum angular velocity is about 24.1°/s), move lateral or move up/down vertical (the maximum velocity is about 0.4m/s). Finally, an example, PID parameters tuning, is given to illustrate the application of maneuverability analysis. The dynamic performance of ZFAUV can be quickly and accurately analyzed by mathematical method, which has important guiding significance for the choice of control strategy and experiments and also has reference value for the later development of AUVs.

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47

Islas-Narvaez, Emmanuel Alejandro, Jean Fulbert Ituna-Yudonago, Luis Enrique Ramos-Velasco, Mario Alejandro Vega-Navarrete i Octavio Garcia-Salazar. "Design and Determination of Aerodynamic Coefficients of a Tail-Sitter Aircraft by Means of CFD Numerical Simulation". Machines 11, nr 1 (23.12.2022): 17. http://dx.doi.org/10.3390/machines11010017.

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Vertical take-off and landing (VTOL) aircraft have become important aerial vehicles for various sectors, such as security, health, and commercial sectors. These vehicles are capable of operating in different flight modes, allowing for the covering of most flight requirements in most environments. A tail-sitter aircraft is a type of VTOL vehicle that has the ability to take off and land vertically on it elevators (its tail) or on some rigid support element that extends behind the trailing edge. Most of the tail-sitter aircraft are designed with a fixed-wing adaptation rather than having their own design. The design of the tail-sitter carried out in this work had the particularity of not being an adaptation of a quad-rotor system in a commercial swept-wing aircraft, but, rather, was made from its own geometry in a twin-rotor configuration. The design was performed using ANSYS SpaceClaim CAD software, and a numerical analysis of the performance was carried out in ANSYS Fluent CFD software. The numerical results were satisfactorily validated with empirical correlations for the calculation of the polar curve, and the performance of the proposed tail-sitter was satisfactory compared to those found in the literature. The results of velocity and pressure contours were obtained for various angles of attack. The force and moment coefficients obtained showed trends similar to those reported in the literature.

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48

Qiu, Fu Sheng, Wu Qiang Ji i Hou Chao Xu. "Vertical Tail Topology Optimization Design Based on the Variable Density Method with Constraint Factor". Applied Mechanics and Materials 300-301 (luty 2013): 280–84. http://dx.doi.org/10.4028/www.scientific.net/amm.300-301.280.

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The topology optimization design problem with multiple constraints for the complex vertical tail structure is studied in this paper. The variable density structural topology optimization method is improved by introducing a constraint factor. According to the different structural constraints and design requirements, variable factors and element pseudo density are initialized via finite element method. This method is controlled by the constraint factors, and the improved method combining with Rational Approximation of Material Properties (RAMP) density-stiffness interpolation model with optimality criteria methods (OC), the vertical tail’s stiffness optimization has been finished. The density-stiffness interpolation model, the mathematical model of variable density method with constraint factor, the structural optimization model, the solution model of the OC method, the design variables iterative format, are given in this paper and the algorithm with Matlab program is realized. Lastly, a sample vertical tail case is introduced to validate the feasibility of the algorithm by operating the results and analyzing the data.

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49

Kim, Myeongjin, Bongsub Song i Dongwon Yun. "Study on the Compact Balance Control Mechanism for Guinea Fowl Jumping Robot". Electronics 11, nr 8 (8.04.2022): 1191. http://dx.doi.org/10.3390/electronics11081191.

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We developed a guinea fowl jumping robot with a one-axis momentum wheel mechanism with a passive hallux model. The Guinea fowl jumping robot was able to perform stable vertical jumping due to the linkage structure designed as a passive hallux model. Furthermore, we used the one-axis momentum wheel mechanism in the jumping robot for making the compact balance control mechanism that can control the body angle of the robot. Through the experiment, the conventional jumping robot uses the inertial tail to adjust the body angle in the air for stable landing and jumping. However, in the case of an inertial tail, it has a large volume and has a disadvantage in that stability is highly reduced when it collides with obstacles due to the shape of the inertial tail. Moreover, we performed a theoretical analysis, simulation, and experiment to verify the performance of the momentum wheel mechanism, and we confirmed that the passive hallux structure contributed to the jumping stability. Besides, we proved that the momentum wheel could adequately land on the ground by adjusting the body angle after vertical jumping. In addition, we demonstrated that the stability of the momentum wheel is higher than the inertial tail through collision simulation.

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Gamble, Lawren L., i Daniel J. Inman. "Yaw Control of a Smart Morphing Tailless Aircraft Concept". Advances in Science and Technology 101 (październik 2016): 127–32. http://dx.doi.org/10.4028/www.scientific.net/ast.101.127.

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Aircraft morphing with regard to UAVs has recently gained incredible momentum; however, only a limited amount of research has been conducted on its effect on tailless aircraft. This is partly due to aerodynamic compromises such as directional instabilities that arise in the absence of a vertical stabilizer. Yet birds readily adapt to adverse flight conditions without vertical stabilizers and are unhindered with respect to stability and maneuvering due to their smooth continuous shape change and rapid muscle response. This research, motivated by the discrepancy between manmade and natural flight designs, investigates the aerodynamic effects of a smart morphing horizontal tail exhibiting bending-twisting coupling for yaw control on a bio-inspired aircraft. The structural response due to actuation was determined using Abaqus and coupled with a Reynolds-averaged-Navier-Stokes turbulence model for a low-Reynolds-number fluid analysis of the deformed shape. The morphing tail was simulated as piezoelectric Macro Fiber Composites with oriented PZT rods. Directional moment and stability derivative are presented to gain insight into the effect of the morphing horizontal tail on yaw control.

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