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Zhang, Yingchao, Ruidong Wang, Chao Yang, Zijie Wang y Zhe Zhang. "Experimental investigation on wake flow structures of Motor Industry Research Association square-back model". Advances in Mechanical Engineering 12, n.º 6 (junio de 2020): 168781402093231. http://dx.doi.org/10.1177/1687814020932313.
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Since the oil crisis of the last century, drag reduction for vehicles has become the focus of researchers. Currently the world’s major car brands have to seize the sport utility vehicle market. However, the sport utility vehicle models usually have a larger frontal area which brings challenges to drag reduction. This requires a better understanding of flow around sport utility vehicle models. The Motor Industry Research Association square-back vehicle model is similar to the sport utility vehicle geometry and can reflect the typical characteristics of aerodynamics of sport utility vehicle models. In this article, the wake flow structures of a 1/8 Motor Industry Research Association model is measured by particle image velocimetry. The results indicate that there is an obviously “n” type backflow vortex behind the vehicle. In the vertical direction, the vortex rotates from the outside to the inside, meanwhile the vortex rotates from the inside to the outside in the longitudinal direction. There is a velocity deficit region between the vortex and the back of the model which is an important source of drag force. This article summarizes the results of particle image velocimetry measurements from the model tests and obtains a picture of the structures of the wake vortex finally which can provide a theoretical basis for the drag reduction research in the future.
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WYCZALEK, FLOYD A. "ULTRA LIGHT ELECTRIC VEHICLES (EV)". Journal of Circuits, Systems and Computers 05, n.º 01 (marzo de 1995): 81–91. http://dx.doi.org/10.1142/s0218126695000072.
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While this project reviewed the status of EV propulsion worldwide, and included European, American, and Japanese electric vehicles and the new Zebra sodium nickel chloride battery introduced by AEG of Daimler Benz at the September 1993 Frankfurt IAA motor show, and the November 1993 Tokyo motor show, this paper is limited in scope to showing results of a mathematical comparison which permits comparative assessment of 1993 EV automotive acceleration performance and the effects of vehicle configuration on the aerodynamic skin friction component of the total aerodynamic drag coefficient. Conclusions are: the major automobile manufacturers have been responsive, creative, and synergistic in developing and demonstrating significant improvements in acceleration performance and vehicle styling configuration strategies which may permit early deployment of ultralight electric vehicles with increased range. Consequently, the battery "Electric Vehicle" now has a brighter future.
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Chen, Zhen, Zhenqqi Gu y Tao Jiang. "Research on transient aerodynamic characteristics of windshield wipers of vehicles". International Journal of Numerical Methods for Heat & Fluid Flow 29, n.º 8 (5 de agosto de 2019): 2870–84. http://dx.doi.org/10.1108/hff-09-2018-0531.
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Purpose The main purpose of this paper is to gain a better understanding of the transient aerodynamic characteristics of moving windshield wipers. In addition, this paper also strives to illustrate and clarify how the wiper motion impacts the airflow structure; the aerodynamic interaction of two wipers is also discussed. Design/methodology/approach A standard vehicle model proposed by the Motor Industry Research Association and a pair of simplified bone wipers are introduced, and a dynamic mesh technique and user-defined functions are used to achieve the wiper motion. Finite volume methods and large eddy simulation (LES) are used to simulate the transient airflow field. The simulation results are validated through the wind tunnel test. Findings The results obtained from the study are presented graphically, and pressure, velocity distributions, airflow structures, aerodynamic drag and lift force are shown. Significant influences of wiper motion on airflow structures are achieved. The maximum value of aerodynamic lift and drag force exists when wipers are rotating and there is a certain change rule. The aerodynamic lift and drag force when wipers are rotating downward is greater than when wipers are rotating upward, and the force when rotating upward is greater than that when steady. The aerodynamic lift and drag forces of the driver-side wiper is greater than those of the passenger-side wiper. Originality/value The LES method in combination with dynamic mesh technique to study the transient aerodynamic characteristics of windshield wipers is relatively new.
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Stabile, Pietro, Federico Ballo, Gianpiero Mastinu y Massimiliano Gobbi. "An Ultra-Efficient Lightweight Electric Vehicle—Power Demand Analysis to Enable Lightweight Construction". Energies 14, n.º 3 (1 de febrero de 2021): 766. http://dx.doi.org/10.3390/en14030766.
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A detailed analysis of the power demand of an ultraefficient lightweight-battery electric vehicle is performed. The aim is to overcome the problem of lightweight electric vehicles that may have a relatively bad environmental impact if their power demand is not extremely reduced. In particular, electric vehicles have a higher environmental impact during the production phase, which should be balanced by a lower impact during the service life by means of a lightweight design. As an example of an ultraefficient electric vehicle, a prototype for the Shell Eco-marathon competition is considered. A “tank-to-wheel” multiphysics model (thermo-electro-mechanical) of the vehicle was developed in “Matlab-Simscape”. The model includes the battery, the DC motors, the motor controller and the vehicle drag forces. A preliminary model validation was performed by considering experimental data acquisitions completed during the 2019 Shell Eco-marathon European competition at the Brooklands Circuit (UK). Numerical simulations are employed to assess the sharing of the energy consumption among the main dissipation sources. From the analysis, we found that the main sources of mechanical dissipation (i.e., rolling resistance, gravitational/inertial force and aerodynamic drag) have the same role in the defining the power consumption of such kind of vehicles. Moreover, the effect of the main vehicle parameters (i.e., mass, aerodynamic coefficient and tire rolling resistance coefficient) on the energy consumption was analyzed through a sensitivity analysis. Results showed a linear correlation between the variation of the parameters and the power demand, with mass exhibiting the highest influence. The results of this study provide fundamental information to address critical decisions for designing new and more efficient lightweight vehicles, as they allow the designer to clearly identify which are the main parameters to keep under control during the design phase and which are the most promising areas of action.
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Kim, Wootaek, Jongchan Noh y Jinwook Lee. "Effects of Vehicle Type and Inter-Vehicle Distance on Aerodynamic Characteristics during Vehicle Platooning". Applied Sciences 11, n.º 9 (30 de abril de 2021): 4096. http://dx.doi.org/10.3390/app11094096.
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Considering the future development in vehicle platooning technology and the multiple models pertaining to complex road environments involving freight cars and general vehicles, the speed and distance of a vehicle model were set as variables in this study. This study aimed at analyzing the effect of currents acting differently using SolidWorks Flow Simulation tool for the vehicle platooning between different models of trucks that are currently being studied actively and sports utility vehicle (SUV) whose market share has been increasing, in order to evaluate the changes in the drag coefficient and their causes. Additionally, purpose-based vehicle (PBV) presented by Hyundai Motor (Ulsan, Korea) during the CES 2020 was considered. In this study, we found that the shape of the rear side of the leading vehicle reduces the drag coefficient of the following vehicle by washing the wake, similar to a spoiler at the rear. The rear side area of the leading vehicle forms a wide range of low pressures, which increases the drag coefficient effect of the following vehicle. The overall height of the leading vehicle also generates a distribution of low pressures above the rear of the vehicle. This reduces the impact of low pressures on the overall height of the following vehicle. The shape of the front of the following vehicle enables the wake of the leading vehicle, which involves low pressures, to inhibit the Bernoulli effect of the following vehicle. Furthermore, the front of the following vehicle continues to be affected by the wake of the leading vehicle, resulting in an increase in the drag coefficient reduction.
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Podrigalo, Mikhail, Volodymyr Krasnokutskyi, Vitaliy Kashkanov, Olexander Tkachenko y Аlexander Yanchik. "Іmprovement of driving-speed properties improvement of the method for selecting the parameters of the motor-transmission unit car". Journal of Mechanical Engineering and Transport 13, n.º 1 (2021): 111–17. http://dx.doi.org/10.31649/2413-4503-2021-13-1-111-117.
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Aerodynamic characteristics have a major impact on the energy efficiency and traction and speed properties of the vehicle. In this article, based on previous studies of the aerodynamic characteristics of various car models, we propose an improved method for selecting engine and transmission parameters at the design stage. The aim of the study is to improve the dynamic properties of the car by improving the method of selecting the main parameters of the engine-transmission unit by refining the calculation of aerodynamic drag. To achieve it, the following tasks must be solved: to specify the method of selecting the maximum effective engine power; to specify a technique of definition of the maximum constructive speed of the car; to develop a technique for selecting gear ratios. The aerodynamic resistance to the movement of the vehicle is determined by the frontal coefficient of the specified resistance, the density of the air, the area of the frontal resistance and the speed of the vehicle. It is known from classical works on the aerodynamics of a car that in the range of vehicle speeds from 20 m / s to 80 m / s, taking the law of squares when assessing the force of air resistance, it is necessary to change the coefficient of frontal aerodynamic drag depending on the speed of the car. However, when carrying out calculations, this coefficient is taken constant, which leads to obtaining large values of the air resistance force at high speeds and lower at low speeds. There are two possible ways to improve the dynamic properties and energy efficiency of the car during its modernization (increasing the maximum design speed of the car by reducing the gear ratio in higher gear; reducing the maximum efficiency of the engine while maintaining the previous gear ratio in higher gear). As a result of the study, the method of selection (maximum effective engine power; maximum design speed of the car; gear ratios) at the design stage of the parameters of the motor-transmission unit of the car has been improved.
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Ilea, L. y D. Iozsa. "Wheels aerodynamics and impact on passenger vehicles drag coefficient". IOP Conference Series: Materials Science and Engineering 444 (29 de noviembre de 2018): 072005. http://dx.doi.org/10.1088/1757-899x/444/7/072005.
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Sharke, Paul. "Smooth Body". Mechanical Engineering 121, n.º 10 (1 de octubre de 1999): 74–77. http://dx.doi.org/10.1115/1.1999-oct-6.
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This article describes features of a car which is General Motors' (GM) technology demonstration entry in the Partnership for a New Generation of Vehicles, the PNGV program. Compared to the EV1, the ultra-efficient two-passenger electric vehicle GM has been selling in California since 1996, the new concept car has 34 fewer counts (0.034) of aerodynamic drag. The engineers needed to establish the vehicle's architecture early, knowing that any mistakes there would be irreversible. They had to evaluate armrest positions and side-window clearance. By wearing its cooling-air intakes on the rear fenders-a benefit that comes with mounting the engine in back—the new shape borrows from sibling EV1's success with low ram air inlet. While the shape investigation was under way, an EV1 test mule aided the concurrent development of features. A full- size model of the technology demonstration shape was ready for wind-tunnel testing by June 1998.
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Kothari, Priyank. "Reduction of Aerodynamic Drag of Heavy Vehicles using CFD". International Journal for Research in Applied Science and Engineering Technology 9, n.º 8 (31 de agosto de 2021): 2670–78. http://dx.doi.org/10.22214/ijraset.2021.37853.
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Abstract: Aerodynamic drag is the force that opposes an object’s motion. When a vehicle no matter the size, is designed to allow air to move fluidly over its body, aerodynamic drag will have less of an impact on its performance and fuel economy. Heavy trucks burn a significant amount of fuel as to overcome the air resistance. More than 50% of an 18-wheeler’s fuel is spent reducing aerodynamic drag on the highways. Keywords: Aerodynamics, Heavy vehicles, ANSYS, Aerodynamic Drag, Fuel efficiency.
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Song, Xiao-wen, Guo-geng Zhang, Yun Wang y Shu-gen Hu. "Use of bionic inspired surfaces for aerodynamic drag reduction on motor vehicle body panels". Journal of Zhejiang University-SCIENCE A 12, n.º 7 (julio de 2011): 543–51. http://dx.doi.org/10.1631/jzus.a1000505.
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Tran, Ngoc Khanh, Van Quang Dao, Phu Khanh Nguyen, Thi Kim Dung Hoang y Van Khang Nguyen. "Numerical Investigations of Aerodynamics Characteristics of Main Rotors in Helicopter UAV Used for Pesticide Spraying in Agriculture". Applied Mechanics and Materials 889 (marzo de 2019): 425–33. http://dx.doi.org/10.4028/www.scientific.net/amm.889.425.
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In the last several decades past, Helicopters UAVs (Unmanned Aerial Vehicles) have quickly developed and day by day, they play an important role in human life. As it is well-known, helicopters UAV make some outstanding characteristics such as light weight, flexibility and particularly automatically controlled. By applying these characteristics, we research and manufacture Helicopter UAV using for spraying pesticide in agriculture. One of the most important components is main rotor because main rotor generated thrust, drag and momentum. Helicopters UAV efficient changed depending on main rotor. The research works focus on aerodynamics characterization of main rotor in helicopter UAV. This work uses CFD tool in ANSYS CFX software to calculate the aerodynamics parameters generated by main rotor using in UAV. The aim is to characterize the aerodynamics characteristics such as thrust, drag, pressure, aerodynamics quality on the different flight modes (hover, vertical and forward flight). Firstly, the simulations are carried out in hover flight mode with different blade pitch angles. The results are compared to experiment date in another research to validate numerical results. Then, the simulations are carried out in vertical flight mode and forward flight mode. The results showed that thrust and drag coefficient creased with increasing blade pitch angle. When blade pitch angle started from 1800, thrust coefficient decreased but drag coefficient increased sharply. The rotor performance was measured by aerodynamics quality and numerical results showed that the best rotor performance was at 900. In the vertical flight mode, the thrust and drag coefficient decreased with increasing vertical velocity but rotor performance increased slightly. The best vertical velocity for vertical flight is around 2 m/s and 3 m/s. Finally, in forward flight mode, the aerodynamics characterizations of rotors depended on azimuthal angular position of blade or time. Our helicopter operates in environment with light gust. The results showed the change of aerodynamics coefficient to time. Both thrust and drag coefficient changed but the rotor performance did not change much.
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Rasidi Rasani, Mohammad, Azhari Shamsudeen, Zambri Harun y Wan Mohd Faizal Wan Mahmood. "A Computational Aerodynamic Study of Tandem Rotating Wheels in Contact with the Ground". International Journal of Engineering & Technology 7, n.º 3.17 (1 de agosto de 2018): 133. http://dx.doi.org/10.14419/ijet.v7i3.17.16637.
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Wheels have significant impact on noise and drag of road vehicles, which may influence their fuel consumption, emission and comfort. A number of studies have analyzed flow and aerodynamics of isolated wheel in contact with the ground, but limited attention has been given to interaction between wheels. The present study aims to compare the aerodynamics and flow structure between single and tandem wheels. To that end, flow around single and tandem wheels are simulated using a turbulence Scaled Adaptive Unsteady Reynolds Average Navier Stokes (URANS) model. Wheel geometry was based on the actual wheel used in the experiments of Fackrell and Harvey. Flow around single and tandem wheels were examined and compared, along with their respective drag and lift coefficients. Results for single wheel in contact with the ground show good agreement with previous experiments. In the tandem wheel case, the rear wheel exhibits lower drag coefficient (CD = 0.37) and more downforce (lift coefficient CL = -0.14) compared to the front wheel. The present investigation may help to illustrate impact of wheel interaction on their aerodynamics.
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Zhang, Zhe, Ying Chao Zhang, Jie Li y Jia Wang. "Numerical Simulation on Aerodynamic Characteristics of Heavy-Duty Commercial Vehicle". Advanced Materials Research 346 (septiembre de 2011): 477–82. http://dx.doi.org/10.4028/www.scientific.net/amr.346.477.
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With the development of automotive technology and high-speed highway construction, the speed of the vehicles increase which cause the significant increase in the aerodynamic drag when road vehicles are moving. Thereby the power of the vehicles, fuel economy, operational stability and other properties are affected very seriously. Heavy-duty commercial vehicles as the most efficient way to transport goods on the highway are widely used, and the speed of the vehicles increases faster. Especially the demands for heavy-duty commercial vehicles are increasing in recent years. Reducing the aerodynamic drag by the analysis of external aerodynamic characteristics, improving the fuel economy and reducing energy consumption have become new research topics of heavy-duty commercial vehicles. To make the heavy-duty commercial vehicles meet the national standards of energy saving, a simplified heavy-duty commercial truck model was built in this paper. The numerical simulation of the vehicle was completed based on the theory of the aerodynamics. The aerodynamic characteristics were analyzed, according to the graphs of the pressure distribution, velocity distribution and flow visualization. To improve the aerodynamic characteristics of heavy-duty commercial vehicles, the main drag reduction measures are reducing the vortex of the cab and the container, the end of the container and the bottom of the container.
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Gnatowska, Renata y Marcin Sosnowski. "The influence of distance between vehicles in platoon on aerodynamic parameters". EPJ Web of Conferences 180 (2018): 02030. http://dx.doi.org/10.1051/epjconf/201818002030.
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The paper presents the results of experimental and numerical research focused on the reduction of fuel consumption of vehicles driving one after another in a so-called platoon arrangement. The aerodynamic parameters and safety issues were analyzed in order to determine the optimal distance between the vehicles in traffic conditions. The experimental research delivered the results concerning the drag and was performed for simplified model of two vehicles positioned in wind tunnel equipped with aerodynamic balance. The additional numerical analysis allowed investigating the pressure and velocity fields as well as other aerodynamics parameters of the test case.
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Hamiga, Władysław y Wojciech Ciesielka. "Numerical investigation of the drag force reduction for homogeneous column of vehicles". New Trends in Production Engineering 2, n.º 1 (1 de octubre de 2019): 524–31. http://dx.doi.org/10.2478/ntpe-2019-0056.
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Abstract This paper presents simulation studies on the aerodynamics of vehicles moving in an organized column. The object of research is a column that consist of three vehicles of the same type (homogeneous column). In this research geometry of Ford Transit was used. As a part of the studies, the air drag forces acting on individual vehicles were calculated. The results are presented in dimensionless drag coefficient. The influence of the distance between cars on the generated force was also determined. In the first stage of the work, a numerical model was developed based on the Ahmed body reference structure. The calculations were carried out for 9 different velocities. The obtained results of the drag coefficient were compared with the work of other authors. The applied turbulence model and parameters of the boundary layer were used to create a numerical model of a moving column of vehicles. Mesh independence for numerical model of van was verified. The Finite Volume Method was implemented in the ANSYS Fluent program and used for the calculations. The use of supercomputers was necessary due to the large size of the grid.
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H. Abdul-Rahman, H. Moria y Mohammad Rasidi Mohammad Rasani. "Aerodynamic study of three cars in tandem using computational fluid dynamics". Journal of Mechanical Engineering and Sciences 15, n.º 3 (19 de septiembre de 2021): 8228–40. http://dx.doi.org/10.15282/15.3.2021.02.0646.
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Aerodynamics of vehicles account for nearly 80% of fuel losses on the road. Today, the use of the Intelligent Transport System (ITS) allows vehicles to be guided at a distance close to each other and has been shown to help reduce the drag coefficients of the vehicles involved. In this article, the aim is to investigate the effect of distances between a three car platoons, to their drag and lift coefficients, using computational fluid dynamics. To that end, a computational fluid dynamics (CFD) simulation was first performed on a single case and platoon of two Ahmed car models using the STAR-CCM+ software, for validation with previous experimental studies. Significant drop in drag coefficients were observed on platoon models compared to a single model. Comparison between the k-w and k-e turbulence models for a two car platoon found that the k-w model more closely approximate the experimental results with errors of only 8.66% compared to 21.14% by k-e turbulence model. Further studies were undertaken to study the effects of various car gaps (0.5L, 1.0L and 1.5L; L = length of the car) to the aerodynamics of a three-car platoon using CFD simulation. Simulation results show that the lowest drag coefficient that impacts on vehicle fuel savings varies depending on the car's position. For the front car, the lowest drag coefficient (CD) can be seen for car gaps corresponding to X1 = 0.5L and X2 = 0.5L, where CD = 0.1217, while its lift coefficient (CL) was 0.0366 (X1 and X2 denoting first to second and second to third car distance respectively). For the middle car, the lowest drag coefficient occurred when X1 = 1.5L and X2 = 0.5L, which is 0.1397. The lift coefficient for this car was -0.0611. Meanwhile, for the last car, the lowest drag coefficient was observed when X1 = 0.5L and X2 = 1.5L, i.e. CD = 0.263. The lift coefficient for this car was 0.0452. In this study, the lowest drag coefficient yields the lowest lift coefficient. The study also found that for even X1 and X2 spacings, the drag coefficient increased steadily from the front to the last car, while the use of different spacings were found to decrease drag coefficient of the rear car compared to the front car and had a positive impact on platoon driving and fuel-saving.
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Bibin, John y Kulkarni Vinayak. "Investigation of Energy Deposition Technique for Drag Reduction at Hypersonic Speeds". Applied Mechanics and Materials 367 (agosto de 2013): 222–27. http://dx.doi.org/10.4028/www.scientific.net/amm.367.222.
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Reduction in aerodynamic heating is the major design concern for hypersonic or hypervelocity vehicles which makes typical configurations blunt nosed for this flow regime. These blunt configurations make the space flight costlier due to higher wave drag. Therefore development and optimization of drag reduction techniques is the field of investigation and research in the area of hypersonic aerodynamics. The present work focuses on the investigation of concentrated energy addition technique for drag reduction. An in-house developed high precision compressible flow solver has been employed for the computational investigation of this technique. Parametric studies are carried out to investigate the effect of strength of energy source, location of energy addition and size of energy source.
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Li, Zhong Jian y Dong Li Ma. "Control Characteristics Analysis of Split-Drag-Rudder". Applied Mechanics and Materials 472 (enero de 2014): 185–90. http://dx.doi.org/10.4028/www.scientific.net/amm.472.185.
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Flying wing configuration is a promising candidate for various kinds of unmanned aerial vehicles. However, this kind of configuration eliminates conventional vertical tail and rudder, thus existing severe problems on yawing control. To make the flying wing configuration into practical use, it is especially necessary to gain a deep understanding on the control characteristics of yawing control devices. To the innovative yawing control device: split-drag-rudder, which is most widely used on flying wing configuration, the paper introduced its current research and mechanical feature, then carefully analyzed its yawing control characteristics, three-axis control coupling effect, also influencing regularities on aerodynamics and stabilities. The conclusions can help to provide basis on engineering application for split-drag-rudder, and to some extent, help to solve the yawing control problem for the flying wing configuration.
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Nazaruddin, Syafri y Yudi Saputra. "Body Shape Selection of "Bono Kampar" For Urban Concept Student Car Formula to Fulfill Indonesian Energy-Saving Standards (“KMHE”) with Aerodynamic Analysis". CFD Letters 12, n.º 12 (31 de diciembre de 2020): 104–14. http://dx.doi.org/10.37934/cfdl.12.12.104114.
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The body shape of a vehicle and the structure need to be considered when designing a vehicle. In addition, the shape of the body tends to significantly affect the vehicle's energy use to counter aerodynamic forces due to wind loads. Therefore, this research aims to determine the body length, width, height, wheel base and ground clearance of vehicles in the selection of Bono Kampar for Urban Concept Car Formula to Fulfill Indonesia Energy-Savings Standards (“KMHE”) with Aerodynamics Analysis. The methods used to create four models of vehicle bodies are dynamic simulation on Computational Fluid Dynamic software are coefficient drag, lift and bland force. The result showed that the car body design needs to have the smallest drag coefficient. This is because when vehicles have a large drag coefficient value, it tends to greatly influence its efficiency or performance. Furthermore, this is useful for minimizing fuel usage, and in allowing the vehicle to reduce the friction force caused by air while driving. The Computational Fluid Dynamic (CFD) software is used to obtain drag coefficients, which is used in Solid works Flow Simulation. From aerodynamic simulation results on four alternative car bodies carried out in this study, the smallest Cd (Coefficient Drag) is the second car body model, which has Drag Coefficient (Cd) of 0.21 Pa.
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Sharma, Vikas y Shubhi Purwar. "Nonlinear Controllers for a Light-Weighted All-Electric Vehicle Using Chebyshev Neural Network". International Journal of Vehicular Technology 2014 (22 de abril de 2014): 1–14. http://dx.doi.org/10.1155/2014/867209.
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Two nonlinear controllers are proposed for a light-weighted all-electric vehicle: Chebyshev neural network based backstepping controller and Chebyshev neural network based optimal adaptive controller. The electric vehicle (EV) is driven by DC motor. Both the controllers use Chebyshev neural network (CNN) to estimate the unknown nonlinearities. The unknown nonlinearities arise as it is not possible to precisely model the dynamics of an EV. Mass of passengers, resistance in the armature winding of the DC motor, aerodynamic drag coefficient and rolling resistance coefficient are assumed to be varying with time. The learning algorithms are derived from Lyapunov stability analysis, so that system-tracking stability and error convergence can be assured in the closed-loop system. The control algorithms for the EV system are developed and a driving cycle test is performed to test the control performance. The effectiveness of the proposed controllers is shown through simulation results.
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Evseev, Kirill, Alexey Dyakov y Roman Pashkovskiy. "Experimental research of motor vehicles on a test bench". MATEC Web of Conferences 329 (2020): 01023. http://dx.doi.org/10.1051/matecconf/202032901023.
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The article presents one of the possible methods for testing wheeled, tracked movers and support skis. The drag coefficient values of lateral tire deflection are obtained using a test bench and measuring equipment. Atmospheric and road conditions are taken into account. The tests can be carried out at various loads and velocities.
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Rubio, Francisco y Carlos Llopis-Albert. "Viability of using wind turbines for electricity generation in electric vehicles". Multidisciplinary Journal for Education, Social and Technological Sciences 6, n.º 1 (20 de mayo de 2019): 115. http://dx.doi.org/10.4995/muse.2019.11743.
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<p class="Textoindependiente21">This paper presents a feasibility study of applying a fluid energy recovery system by means of wind turbines for charging batteries of electric vehicles. This is because the main disadvantage of electric vehicles with regard to conventional fuel automobiles is the scarce capacity of storing sufficient energy to run long distances. This can be carried out by recovering a percentage of the energy used to overcome the aerodynamic drag of the vehicle. This work analysis different case studies, with different driving modes, to quantify the theoretical energy recovered from the vehicle aerodynamics. Results have shown the theoretical possibility to implement this technology in actual electric vehicles.</p>
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Dubovik, V. N., V. T. Zhukov, K. V. Manukovskii, N. D. Novikova, D. V. Tulin y O. B. Feodoritova. "Parametric Calculations of the Aerodynamics of a Descent Vehicle". Herald of the Bauman Moscow State Technical University. Series Natural Sciences, n.º 2 (95) (abril de 2021): 37–51. http://dx.doi.org/10.18698/1812-3368-2021-2-37-51.
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We present the methodology and results of parametric aerodynamic studies of vehicles descending into the planet’s atmosphere. The proposed computational approach might serve as the basis for solving a number of problems such as predicting and optimizing the descent trajectory of the vehicle, the search for a rational aerodynamic layout of the vehicle, i.e., tasks requiring massive parametric calculations. The systematization of such calculations is the first step towards the creation of a specialized database that includes sets of input and output data (flight speed, angles of attack, drag and lift coefficients, aerodynamic pitching moment, etc.) and the corresponding three-dimensional fields of gas-dynamic quantities together with computational meshes of various granularity and parameters of the computational model. Additional information to each element of the database might be a set of variables, parameterizing the geometry of the vehicle, experimental data, etc. The probability of forming the information content of such a data-base using modern supercomputer systems is shown. The capabilities of the domestic supercomputer aerodynamic code NOISEtte are demonstrated in the field of multiparametric three-dimensional calculations of descent vehicles based on the numerical solution of the Navier --- Stokes equations on three-dimensional unstructured meshes
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Hamiga, Władysław y Wojciech Ciesielka. "Numerical modeling of airflow over column of vehicles using Ansys® package". E3S Web of Conferences 46 (2018): 00025. http://dx.doi.org/10.1051/e3sconf/20184600025.
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Growing needs in transportation determinate systems development which improve efficiency of travel and reduce harmful influence to environment. Computational Fluid Dynamic (CFD) uses numerical analysis to find optimal solutions in terms of chosen objective function. Time save and reduce costs for experiments on prototypes are one of the advantages of this method. The aim of this research is to analyze airflow around different motor vehicles which are moving together in the same direction. To reduce fuel consumption and, at the same time, decrease negative influence to environment, the primary target was reducing total drag force during a ride. The vehicles were set in a column - one after another. In this work considered three types of vehicles: Car, Van and a Truck. Presented vehicles were organized into appropriate groups, creating different configuration. Additional parameter in simulation was distance between vehicles. Simulations of singular vehicles were also done. It allows to evaluate influence of moving vehicles in a column for generated drag force. Described traffic situation were modeled and numerically calculated using ANSYS® package. The purpose of this work was to assess the impact of the distance between vehicles, in a given configuration, for generated drag force.
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Xiangming, Zeng y Zhang Huawu. "Experimental Study of the Aerodynamics of Sail in Natural Wind". Polish Maritime Research 25, s2 (1 de agosto de 2018): 17–22. http://dx.doi.org/10.2478/pomr-2018-0068.
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Abstract In order to evaluate the impacts of a motor vessel after installing wind sails, the aerodynamics of the sail should be accurately calculated. However most of the research on sails are based on stable wind instead of natural wind which is changing horizontally and vertically. In this paper wind tunnel tests are carried out based on stable wind field and simulated natural wind field, the results shown that there are 16–44% decrease in natural wind in terms of lifting coefficient and 11–42% decrease for drag coefficient. This would provide a valuable reference to the effectiveness evaluation of the impact of sails for sail assisted ships.
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Le Good, Geoffrey, Max Resnick, Peter Boardman y Brian Clough. "An Investigation of Aerodynamic Effects of Body Morphing for Passenger Cars in Close-Proximity". Fluids 6, n.º 2 (1 de febrero de 2021): 64. http://dx.doi.org/10.3390/fluids6020064.
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The potential energy-saving benefit for vehicles when travelling in a ‘platoon’ formation results from the reduction in total aerodynamic drag which may result from the interaction of bluff bodies in close-proximity. Early investigations of platooning, prompted by problems of congestion, had shown the potential for drag reduction but was not pursued. More recently, technologies developed for connected-autonomous vehicle control have provided a renewed interest in platooning particularly within the commercial vehicle industry. To date, most aerodynamics-based considerations of platooning have been conducted to assess the sensitivity of drag-saving to vehicle spacing and were based on formations of identically shaped constituents. In this study, the interest was the sensitivity of drag-saving to the shape of the individual platoon constituents. A new reference car, the Resnick model, was specially designed to include front and rear-end add-on sections to make distinct changes in profile form and simulate large-scale body morphing. The results of wind tunnel tests on small-scale models suggested that current trends in low-drag styling may not provide the ideal shape for platoon constituent members and that optimised forms are likely to be dependent upon position in the platoon.
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Larose, Guy, Leanna Belluz, Ian Whittal, Marc Belzile, Ryan Klomp y Andreas Schmitt. "Evaluation of the Aerodynamics of Drag Reduction Technologies for Light-duty Vehicles: a Comprehensive Wind Tunnel Study". SAE International Journal of Passenger Cars - Mechanical Systems 9, n.º 2 (5 de abril de 2016): 772–84. http://dx.doi.org/10.4271/2016-01-1613.
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Geropp, D. y H. J. Odenthal. "Drag reduction of motor vehicles by active flow control using the Coanda effect". Experiments in Fluids 28, n.º 1 (1 de enero de 2000): 74–85. http://dx.doi.org/10.1007/s003480050010.
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Barros, Diogo, Jacques Borée, Bernd R. Noack, Andreas Spohn y Tony Ruiz. "Bluff body drag manipulation using pulsed jets and Coanda effect". Journal of Fluid Mechanics 805 (20 de septiembre de 2016): 422–59. http://dx.doi.org/10.1017/jfm.2016.508.
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The impact of fluidic actuation on the wake and drag of a three-dimensional blunt body is investigated experimentally. Jets blowing tangentially to the main flow force the wake with variable frequency and amplitude. Depending on the forcing conditions, two flow regimes can be distinguished. First, in the case of broadband actuation with frequencies comprising the natural wake time scale, the convection of the jet structures enhances wake entrainment, shortens the length of the recirculating flow and increases drag. Secondly, at higher actuation frequencies, shear-layer deviation leads to fluidic boat tailing of the wake. It additionally lowers its turbulent kinetic energy thus reducing the entrainment of momentum towards the recirculating flow. The combination of both mechanisms produces a rise in the base pressure and reduces the drag of the model. Both actuation regimes are characterized by complementary velocity, pressure and drag measurements at several upstream conditions and control parameters. By adding curved surfaces to deviate the jets by the Coanda effect, periodic actuation is reinforced and drag reductions of approximately 20 % are achieved. The unsteady Coanda blowing not only intensifies the flow deviation and the base pressure recovery but also preserves the unsteady high-frequency forcing effect on the turbulent field. The present results encourage further development of fluidic control to improve the aerodynamics of road vehicles and provide a complementary insight into the relation between wake dynamics and drag.
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Szwedziak, Katarzyna, Tomasz Lusiak, Zaneta Grzywacz y Kacper Drozd. "Numerical CFD Analysis of an Aerodynamic Head Cover of a Rotorcraft Motor". Communications - Scientific letters of the University of Zilina 20, n.º 3 (30 de septiembre de 2018): 42–47. http://dx.doi.org/10.26552/com.c.2018.3.42-47.
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Autogyros can become an alternative for the use of rotorcrafts in various fields of life, including agroforestry. They have better economic performance than helicopters, owing to, among other things, the presence of a bearing rotor. Most autogyros also have other advantages in terms of no need for the compliance with stringent regulatory regulations – with respect to new constructions, lower combustion, noise and emissions of toxic elements. The cover of the bearing rotor head is an important element of rotorcrafts, which demonstrates that aerodynamics plays an important role in aerodynamic designs. Therefore, in this article, air flow model testing is carried out for two types of the bearing rotor blades of an autogyro with and without a cover using the ANSYS Fluent program. An aerodynamic drag analysis was also performed.
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Niemyi, S. y V. Brytkovskyi. "EFFICIENCY OF THE HEATING SYSTEM OF THE DRIVER'S WORKPLACE AND THE VESSEL OF THE WINDSHIELD OF BUSES". Bulletin of Lviv State University of Life Safety 23 (1 de julio de 2021): 53–60. http://dx.doi.org/10.32447/20784643.23.2021.08.
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Introduction. One of the dominant areas of improvement of motor vehicles is to improve traffic safety. An im-portant aspect of bus safety is visibility from the driver's workplace, which largely depends on the condition of the wind-shield, especially the absence of fogging and frost, which often occurs at low ambient temperatures.Methodically, this problem is eliminated by blowing the windshield with warm air. Structurally, this is done by devices that, in addition to blowing the windshield, also supply warm air to the driver's workplace. Fogging and icing of the windshield significantly impair the visibility of the road driver, which is a great danger in the movement of the bus. Elimination of icing and fogging of windows provides an increase of visibility and guarantee of safety of driving.An important place is also occupied by the problem of reducing heating systems and blowing operating energy costs, improving the fuel economy of buses.Results. The purpose of the study is to determine the effectiveness of the windshield blowing devices of the bus depending on their design features. As criteria in researches productivity of system blowing, its power consumption and level of noise loading of the driver are accepted.To select a fan with optimal characteristics when used in the device for blowing the windshield of buses and heating the driver's workplace, axial fans were tested. They are using in heating and ventilation systems of buses of different models. It is experimentally established that the fan of the Elko-A200-22 model (Italy) has the best characteris-tics. In the whole range of speed changes, the performance of this fan is much higher compared to other models of the tested fans, which, at the same time, have much higher specific energy consumption. In addition, the fan of this model is characterized by a lower noise level compared to fans of other models with the same outer diameters.Conclusions. Analysis of experimental data shows that the performance of the front heater with two fans and one fan is almost the same. At identical speed modes of operation, the productivity of two fans running in parallel is higher by only 3 ... 16.75%. When measuring the speed of air movement when blowing the windshield, it was found that the speed of blowing does not depend on the number of fans and depends on their performance and the diameter of the air supply hoses to the blowing nozzles.The reason for the lower efficiency of heaters with two fans is that at the outlet after the radiator, in the limited volume of the heater housing, two fans create a much greater aerodynamic drag (back pressure) than one fan.The use of one fan instead of two in the design of bus heaters reduces the electricity consumption of the bus and improves the working conditions of the driver by reducing the noise level at his workplace.
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Kulak, Michal, Maciej Karczewski, Pawel Lesniewicz, Krzysztof Olasek, Bas Hoogterp, Guillaume Spolaore y Krzysztof Józwik. "Numerical and experimental analysis of rotating wheel in contact with the ground". International Journal of Numerical Methods for Heat & Fluid Flow 28, n.º 5 (8 de mayo de 2018): 1203–17. http://dx.doi.org/10.1108/hff-06-2017-0257.
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Purpose This paper aims to provide the results of investigations concerning an influence of the tyre with longitudinal grooves on the car body aerodynamics. It is considered as an important aspect affecting the vehicle aerodynamic drag. Design/methodology/approach To investigate a contribution of grooved tyres to the overall vehicle drag, three wind tunnel experimental campaigns were performed (two by Peugeot Société Anonyme Peugeot Citroen, one at the Lodz University of Technology). In parallel, computational fluid dynamics (CFD) simulations were conducted with the ANSYS CFX software to enable formulation of wider conclusions. Findings The research shows that optimised tread patterns can be derived on a single tyre via a CFD study in combination with a controlled experiment to deliver designs actively lowering the overall vehicle aerodynamic drag. Practical implications A reduction in the aerodynamic drag is one of ways to decrease vehicle fuel consumption. Alternatively, it can be translated into an increase in the maximum travel velocity and the maximum distance driven (key factor in electric vehicles), as well as in a reduction of CO2 emissions. Finally, it can improve the vehicle driving and steering stability. Originality/value The tyre tread pattern analysis on isolated wheels provides an opportunity to cut costs of R&D and could be a step towards isolating aerodynamic properties of tyres, irrespective of the car body on which they are applied.
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Sun, Dong Ru, Xiao Jie Ye, Liang Cheng, Yi Hua Yao y Yun Yue Ye. "Control System Design of Improved Vertical Lifting Stereo Garage with Linear Motor as Transverse Device". Applied Mechanics and Materials 416-417 (septiembre de 2013): 940–45. http://dx.doi.org/10.4028/www.scientific.net/amm.416-417.940.
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Rotating induction motor serving as transverse device in traditional stereo garage makes system complex and inefficient. Installing linear motor in lifting platform as direct drive unit can remove intermediate links and drag vehicle loading board of parking slot directly. In this paper, control system of vertical lifting stereo garage with linear induction motor is put forward, including overall organization, operating principle and software program.Linear motor is controlled by Programmable Logic Controller (PLC) in slip frequency control method and PI algorithm. Experiment results indicate that linear motor can track reference velocitycurveand the whole stereo garage can store and take out vehicles automatically and efficiently.
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Jana, Shuvrangshu, Harikumar Kandath, Mayur Shewale y M. Seetharama Bhat. "Effect of propeller-induced flow on the performance of biplane micro air vehicle dynamics". Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, n.º 3 (8 de noviembre de 2019): 716–28. http://dx.doi.org/10.1177/0954410019883097.
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This paper presents the analysis of propeller-induced flow effects on the dynamics of a fixed wing biplane micro air vehicle. The analysis is based on wind tunnel tests and mathematical modeling. This analysis plays a pivotal role because the propeller-induced flow has significant effects on the dynamics of fixed wing micro air vehicle due to submergence of a large portion of the wing in propeller slipstream. Although the effect of the propeller-induced flow on the various aerodynamic parameter is reported in the literature; however, its effects on overall forces, moments and vehicle dynamics are not quantified so far. In this paper, propeller-induced flow effects are modeled as a function of motor rotation speed and mathematical analysis is performed to quantify their effects. The wind tunnel test is conducted at different propeller speeds on a biplane micro air vehicle “Skylark”, having wingspan and chord length of 150 mm and 140 mm, respectively. Analysis of results shows that the propeller slipstream increases the overall lift, drag, side force, range, and endurance significantly. Propeller flow also contributes to the rolling moment and the pitching moment, while it has negligible effects on the yawing moment. It is shown that the trim angle of attack is lower when the propeller flow is considered in computing the trim conditions.
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V., Somashekar y Immanuel Selwyn Raj A. "Numerical and experimental study of the laminar separation bubble over SS007 airfoil for micro aerial vehicles". Aircraft Engineering and Aerospace Technology 92, n.º 8 (14 de junio de 2020): 1125–31. http://dx.doi.org/10.1108/aeat-12-2019-0252.
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Purpose This paper aims to deal with the numerical investigation of laminar separation bubble (LSB) characteristics (length and height of the bubble) of SS007 airfoil at the chord Reynolds number of Rec = 0.68 × 105 to 10.28 × 105. Design/methodology/approach The numerical simulations of the flow around SS007 airfoil were carried out by using the commercial fluid dynamics (CFD) software, ANalysis system (ANSYS) 15. To solve the governing equations of the flow, a cell-centred control volume space discretisation approach is used. Wind tunnel experiments were conducted at the chord-based Reynolds number of Rec = 1.6 × 105 to validate the aerodynamic characteristics over SS007 airfoil. Findings The numerical results revealed that the LSB characteristics of a SS007 airfoil, and the aerodynamic performances are validated with experimental results. The lift and drag coefficients for both numerical and experimental results show very good correlation at Reynolds number 1.6 × 105. The lift coefficient linearly increases with the increasing angle of attack (AOA) is relatively small. The corresponding drag coefficient was found to be very small. After the formation of LSB which leads to burst to cause airfoil stall, the lift coefficient decreases and increases the drag coefficient. Practical implications Low Reynolds number and LSB characteristics concept in aerodynamics is predominant for both civilian and military applications. These include high altitude devices, wind turbines, human powered vehicles, remotely piloted vehicles, sailplanes, unmanned aerial vehicle and micro aerial vehicle. In this paper, the micro aerial vehicle flight conditions considered and investigated the LSB characteristics for different Reynolds number. To have better aerodynamic performances, it is strongly recommended to micro aerial vehicle (MAV) design engineers that the MAV is to fly at 12 m/s (cruise speed). Social implications MAVs and unmanned aerial vehicles seem to give some of the technical challenges of nature conservation monitoring and law enforcement a versatile, reliable and inexpensive solution. Originality/value The SS007 airfoil delays the flow separation and improves the aerodynamic efficiency by increasing the lift and decreasing the drag. The maximum increase in aerodynamic efficiency is 12.5% at stall angle of attack compared to the reference airfoil at Re = 2 × 105. The results are encouraging and this airfoil could have better aerodynamic performance for the development of MAV.
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Bodavula, Aslesha, Rajesh Yadav y Ugur Guven. "Numerical investigation of the unsteady aerodynamics of NACA 0012 with suction surface protrusion". Aircraft Engineering and Aerospace Technology 92, n.º 2 (21 de noviembre de 2019): 186–200. http://dx.doi.org/10.1108/aeat-01-2019-0022.
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Purpose The purpose of this paper is to investigate the effect of surface protrusions on the flow unsteadiness of NACA 0012 at a Reynolds number of 100,000. Design/methodology/approach Effect of protrusions is investigated through numerical simulation of two-dimensional Navier–Stokes equations using a finite volume solver. Turbulent stresses are resolved through the transition Shear stress transport (four-equation) turbulence model. Findings The small protrusion located at 0.05c and 0.1c significantly improve the lift coefficient by up to 36% in the post-stall regime. It also alleviates the leading edge stall. The larger protrusions increase the drag significantly along with significant degradation of lift characteristics in the pre-stall regime as well. The smaller protrusions also increase the frequency of the vortex shedding. Originality/value The effect of macroscopic protrusions or deposits in rarely investigated. The delay in stall shown by smaller protrusions can be beneficial to micro aerial vehicles. The smaller protrusions increase the frequency of the vortex shedding, and hence, can be used as a tool to enhance energy production for energy harvesters based on vortex-induced vibrations and oscillating wing philosophy.
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Ristroph, Leif, Gunnar Ristroph, Svetlana Morozova, Attila J. Bergou, Song Chang, John Guckenheimer, Z. Jane Wang y Itai Cohen. "Active and passive stabilization of body pitch in insect flight". Journal of The Royal Society Interface 10, n.º 85 (6 de agosto de 2013): 20130237. http://dx.doi.org/10.1098/rsif.2013.0237.
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Flying insects have evolved sophisticated sensory–motor systems, and here we argue that such systems are used to keep upright against intrinsic flight instabilities. We describe a theory that predicts the instability growth rate in body pitch from flapping-wing aerodynamics and reveals two ways of achieving balanced flight: active control with sufficiently rapid reactions and passive stabilization with high body drag. By glueing magnets to fruit flies and perturbing their flight using magnetic impulses, we show that these insects employ active control that is indeed fast relative to the instability. Moreover, we find that fruit flies with their control sensors disabled can keep upright if high-drag fibres are also attached to their bodies, an observation consistent with our prediction for the passive stability condition. Finally, we extend this framework to unify the control strategies used by hovering animals and also furnish criteria for achieving pitch stability in flapping-wing robots.
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Oţăt, Oana Victoria, Ilie Dumitru, Victor Oţăt, Dragos Tutunea y Lucian Matei. "An Applied Study on the Influence of the Vehicle Body Shape on Air Resistance". Applied Mechanics and Materials 896 (febrero de 2020): 141–50. http://dx.doi.org/10.4028/www.scientific.net/amm.896.141.
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The current high-geared developments within the automotive sector have triggered a series of performance, comfort, safety and design-related issues. Hence, oftentimes manufacturers are challenged to combine various elements so as to achieve an attractive design, without diminishing the vehicle’s dynamic performance. Under the circumstances, the shape of the vehicle body becomes the key element that connects the design component with the performance requirement, since it directly influences the value of the resistance forces, and, respectively the air resistance. Aerodynamics is the branch of mechanical engineering that deals with the movement of gases (especially the air) and their effects on fluids. As far as the automotive sector is concerned, aerodynamics focuses mainly on the flow of the air currents over the vehicle body. When designing vehicle, the positive or negative displacement of the airflow is studied in aerodynamic tunnels. It is preferable for the negative displacement to push the vehicle as close to the ground as possible. In what follows we set out to study the influence of the drag coefficient and, implicitly, of the air resistance on vehicle performance. Hence, we will carry out comparative analysis of two vehicles with similar technical characteristics, but with different bodies, i.e. a hatchback and a sedan. The results obtained are then compared both by means of the analytical determination of the air resistance and via a simulation performed within the Virtual Crash software platform. The results recorded show that of the two vehicles, with the considered aerodynamic coefficients, hatchback type vehicle displays lower values in terms of air resistance.
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Xingzhi, Hu. "Anti–Drag Braking Control Technology for Electric Drive Dump Truc". Electrotehnica, Electronica, Automatica 69, n.º 1 (15 de febrero de 2021): 30–36. http://dx.doi.org/10.46904/eea.21.69.1.1108004.
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The power transmission system of electric wheel vehicle with "Power generator - diode rectifier - inverter - traction motor" can achieve part of the braking energy recycling and reduce fuel consumption through the reverse flow of energy in the downhill braking conditions. For AC - DC - AC transmission system of electric wheel vehicles. In order to achieve the engine anti-drag starting smoothly through the introduction of the theory of Engine Anti - drag Braking and the observation of the rotor frequency by external speed sensor, in addition to that zero-crossing detection phase method to achieve the stator rotating magnetic field and rotor speed synchronization purposes. Through use the rectifier inverter module to achieve energy bi-directional transmission and to achieve engine anti-drag when the vehicle goes downhill slowly. In the article, design of engine brake anti-drag control system and the establishment of anti-drag brake power calculation mathematical model, also build the anti-drag test platform of the engine to verify the control system. The experimental results show that the proposed control scheme for the start of the inverter is simple and reliable, which provides the theoretical basis and experimental data for the actual vehicle design.
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Wong, Seng Man, Hann Woei Ho y Mohd Zulkifly Abdullah. "Design and Fabrication of a Dual Rotor-Embedded Wing Vertical Take-Off and Landing Unmanned Aerial Vehicle". Unmanned Systems 09, n.º 01 (2 de octubre de 2020): 45–63. http://dx.doi.org/10.1142/s2301385021500096.
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The interest in building hybrid Unmanned Aerial Vehicles (UAVs) is increasing intensively due to its capability to perform Vertical Take-Off and Landing (VTOL), in addition to forward flight. With this capability, the hybrid UAVs are highly on demand in various industries. In this paper, a fixed-wing VTOL UAV with a novel configuration of a dual rotor-embedded wing was designed and developed. The methodology used in the design process adopted the traditional sizing and aerodynamic estimation method with advanced computational simulations and estimation approaches. The design was determined based on a thorough analysis of weight contribution, aerodynamics, propulsion, and stability and control. The results show that the UAV’s preliminary design has successfully reached a total weight of 1.318 kg, achieved a high lift-to-drag ratio of approximately 4, and ensured stable flights with Level 1 flying qualities. A fixed-wing VTOL prototype was developed and fabricated based on the final design parameters using a low-cost hand lay-up process.
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Heryawan, Yudi, Hoon Cheol Park, Nam Seo Goo, Kwang Joon Yoon y Yung Hwan Byun. "Structural Design, Manufacturing, and Wind Tunnel Test of a Small Expandable Wing". Key Engineering Materials 306-308 (marzo de 2006): 1157–62. http://dx.doi.org/10.4028/www.scientific.net/kem.306-308.1157.
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This paper describes design, manufacturing, and wind tunnel test of a motor-driven small-scale expandable wing for MAV class vehicles. The bird-like expandable wing has been developed for investigating the influence of aspect ratio change on the lift and drag of the wing. As a typical bird wing, the wing is separated into inner and outer wings. The wing model consists of the linkage system made of carbon composite strip/rod and the remaining part covered with carbon composite sheet and multiple LIPCAs (Lightweight Piezo-Composite Actuators) mimicking wing feathers. The LIPCA actuator was used to control wing camber, which created additional lift. Wind tunnel tests were conducted to investigate the changes in lift and drag during wing folding and expansion, and to observe the influence of LIPCA actuation on the wing. In the tests, effects of the wing fold/expansion and actuation of LIPCA on changes in lift and drag were quantitatively identified.
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Nuszkowski, John, Harlan Smith, Michael McKinney, Nicholas McMahan, Benjamin Wilder, Eric Boehringer, Blair Clarkson, Cutler Littleton y Kyle Parker. "Increasing the on-road fuel economy by trailing at a safe distance". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, n.º 9 (30 de abril de 2017): 1303–11. http://dx.doi.org/10.1177/0954407017703233.
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Energy is a driving force for automotive applications. Reducing the energy demand of the vehicle is one method of increasing the fuel economy of a vehicle. Heavy-duty commercial vehicles have large frontal areas that provide large amounts of aerodynamic drag at highway speeds. Reducing the aerodynamic drag lowers the engine demand and therefore increases the fuel economy of the vehicle. This study tested the fuel economy and the front air velocity of a 10.7 m box truck trailing another box truck by distances of 3.1 times the truck length, 4.7 times the truck length, and 6.3 times the truck length at a highway speed of 28 m/s. The distance of 6.3 times the vehicle length was considered ‘safe’ for trailing another vehicle, whereas the distances of 3.1 times the truck length and 4.7 times the truck length were not considered safe by the United States Fire Administration. The results showed significant reductions in the air velocity in front of the trailing vehicle of 8.5%, 6.5%, and 3.8% for trailing distances of 3.1 times the vehicle length, 4.7 times the vehicle length, and 6.3 times the vehicle length respectively. The fuel economy of the trailing truck increased significantly by 7.4–8.0%, 8.2–9.0%, and 6.5%–7.7%, for trailing distances of 3.1 times the vehicle length, 4.7 times the vehicle length, and 6.3 times the vehicle length respectively. Based on a road load analysis, these fuel economy improvements indicated a reduction in the drag coefficient of the trailing vehicle of 8–10%. Therefore, a box truck trailing another box truck at a safe distance results in a reduction in the aerodynamics drag and a significant increase in the fuel economy.
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Gangadharan, Sathya N. y Heinz L. Krein. "Jet-Propelled Remote-Operated Underwater Vehicles Guided by Tilting Nozzles". Marine Technology and SNAME News 26, n.º 02 (1 de abril de 1989): 131–44. http://dx.doi.org/10.5957/mt1.1989.26.2.131.
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This paper is a study and experimental analysis of a forced jet propulsion system with tilting-type nozzles for slow-moving remotely operated underwater vehicles (ROV's). A test setup simulating the motion of the underwater vehicle was fabricated to investigate the effect of nozzle configurations on the propulsion of such vehicles. Plexiglass nozzles of different conical contraction angles (θ = 4 to 28 deg), different conical expansion angles (θ = 3 to 9 deg), and a straight cylindrical section were used in the study. Tests were carried out underwater, and the parameters measured include thrust, flow rate, angular velocity, and total head. Different circular disk type drag plates were used to simulate the drag of the vehicle underwater. Efficiency of propulsion is the criterion for comparing the performance of each nozzle. An expression for the optimum efficiency was derived neglecting the effect of inlet head recovery, which can be assumed for slow-moving vehicles. The energy loss and loss coefficients in submerged propulsion nozzles were found both theoretically and experimentally. A proposal for the fabrication and testing of an innovative design of a jet-propelled ROV guided by tilting nozzles is presented. The design uses a stepper motor for tilting the nozzles. A comparison is made between stationary and swivel-type configurations. The nozzles were tested for optimum area ratio. The propulsion system and the ROV was designed and checked for stability. The study revealed that for a range of flow rates, one particular nozzle was the most efficient compared to other nozzles.
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Nabawy, Mostafa R. A. y Ruta Marcinkeviciute. "Scalability of resonant motor-driven flapping wing propulsion systems". Royal Society Open Science 8, n.º 9 (septiembre de 2021): 210452. http://dx.doi.org/10.1098/rsos.210452.
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This work aims to develop an integrated conceptual design process to assess the scalability and performance of propulsion systems of resonant motor-driven flapping wing vehicles. The developed process allows designers to explore the interaction between electrical, mechanical and aerodynamic domains in a single transparent design environment. Wings are modelled based on a quasi-steady treatment that evaluates aerodynamics from geometry and kinematic information. System mechanics is modelled as a damped second-order dynamic system operating at resonance with nonlinear aerodynamic damping. Motors are modelled using standard equations that relate operational parameters and AC voltage input. Design scaling laws are developed using available data based on current levels of technology. The design method provides insights into the effects of changing core design variables such as the actuator size, actuator mass fraction and pitching kinematics on the overall design solution. It is shown that system efficiency achieves peak values of 30–36% at motor masses of 0.5–1 g when a constant angle of attack kinematics is employed. While sinusoidal angle of attack kinematics demands more aerodynamic and electric powers compared with the constant angle of attack case, sinusoidal angle of attack kinematics can lead to a maximum difference of around 15% in peak system efficiency.
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Choi, Kyungwho, Mun-Young Hwang, Donghoon Kang, Myeongcheol Kang, Dahoon Ahn y Lae-Hyong Kang. "Impact monitoring characteristics of piezoelectric paint sensor by thermal fatigue analysis for railroad vehicle applications". Structural Health Monitoring 19, n.º 6 (6 de abril de 2020): 1951–62. http://dx.doi.org/10.1177/1475921720902274.
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The strong aerodynamic drag under a railroad vehicle in motion causes the track ballast to fly up and around. The flying ballast can collide with the underside of the coach, damaging the electronics installed there. There are even cases wherein the aerodynamics of fast-moving train causes the gravel to hit the side of the coach and break the windows. Extensive and numerous studies are underway to reduce the damage caused by such phenomena. In this study, a “smart paint sensor” for impact monitoring was fabricated using piezoelectric nano powder and commercial paint for railroad vehicles, and the application of impact monitoring to railroad vehicles was analyzed. The process was simplified because the use of commercial paint eliminated the need to apply an additional layer of functionalized paint. Furthermore, the fact that the paint can be evenly sprayed on a large surface made it suitable for use on large and intricate objects such as a railroad vehicle bogie. Because railroad vehicles are exposed to thermal stress for a long period of time, a thermal fatigue test was conducted in order to figure out the stability of the polymer-based material, which is relatively vulnerable to temperature variations. The test results were used to analyze the impact sensitivity of the piezoelectric paint sensor. For the analysis, a full-size mock-up of the railroad vehicle bogie and an impact monitoring system with piezoelectric paint sensor were implemented in order to visualize the impact signals from differently shaped objects with large surfaces.
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A, Mugeshwaran, Guru Prasad Bacha y Rajkumar S. "Design and experimental analysis of morphing wing based on biomimicry". International Journal of Engineering & Technology 7, n.º 3.3 (8 de junio de 2018): 239. http://dx.doi.org/10.14419/ijet.v7i2.33.14160.
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In this paper narrate about the study of aerodynamics in the multi-section morphing wing variation of baseline configuration to camber con-figuration. In particularly NACA 0012, section tried to morph as NACA 9312 camber section to achieve the lift to drag ratio in the flight condition based on the bio-mimicry. The CAD model and fabricated morphing wing in geometry scale of 20 cm chord and a 36 cm wing-span, with aluminum material ribs divided into 6 sections. Each section was able to rotate approximately 6 degrees without causing a discon-tinuity in the wing surface and also in order avoid the control surface based on the bio mimicry the morphing wing was designed and tested. DC-motor located at main spar with the two equal gear ratio the rib section used to morph the wing through the linear mechanical linkages. The aluminum ribs section are made through the EDM-Wire cut machining process for capable to actuate the morphing wing. In each sec-tion morphing wing can able provide up to 10 percent variation in the symmetrical airfoil to the cambered airfoil. The experimental test of the morphing was carried out in the cascade tunnel by force balancing method and the lift and drag output are compared.
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Chodnicki, Marcin, Michal Mazur, Miroslaw Nowakowski y Grzegorz Kowaleczko. "The mathematical model of UAV vertical take-off and landing". Aircraft Engineering and Aerospace Technology 91, n.º 2 (4 de febrero de 2019): 249–56. http://dx.doi.org/10.1108/aeat-01-2018-0041.
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Purpose This paper aims to present a mathematical model of the dynamics of the unmanned aerial vehicle (UAV) vertical take-off and landing (VTOL). It will be used to develop control laws to a multirotor that is inherently unstable. Also, the model will be used to design algorithms to estimate the attitude of an object. Design/methodology/approach The physical model of UAV assumes that it is a rigid body with six degrees of freedom acted by forces generated by the propellers, motors, aerodynamic forces, gravity and disturbance forces. The mathematical model was described by differential equations. However, drive system (propeller, BLDC motor and BLDC motor controller) was described by six transfer functions. These transfer functions were demarcated with Matlab/Simulink identification toolbox from data received from a specially designed laboratory stand. Moments of inertia of the platform have been analytically determined and compared with empirical results from the pendulum. The mathematical model was implemented in Matlab/Simulink. Findings The paper confirms the need of designing mathematical models. Moreover, mathematical models show that some parts of the object are better to be replaced by experimental results than by equations, which is proved by the data. The paper also shows advantages of using Matlab/Simulink. What is more the simulation of the model proves that multirotor is an unstable object. Research limitations/implications The test results show that drive units are strongly dependent on ambient conditions. An additional problem is the different response of the drive set to increasing and decreasing the control signal amplitude. Next tests will be done at different temperatures and air densities of the environment, also it is need to explore drag forces. Practical implications The mathematical model is a simplification of the physical model expressed by means of equations. The results of simulation like accelerations and angular rate are noise-free. However, available sensors always have their errors and noise. To design control loops and attitude estimation algorithms, there is a need for identification of sensors’ errors and noise. These parameters have to be measured. Originality/value The paper describes a solution of correct identification of drive unit, which is a main component of the UAV.
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Tahani, Mojtaba, Mehran Masdari y Ali Bargestan. "Aerodynamic ground effects on DLRF6 vehicle". Aircraft Engineering and Aerospace Technology 93, n.º 5 (14 de junio de 2021): 755–67. http://dx.doi.org/10.1108/aeat-12-2018-0306.
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Purpose The overall performance of an aerial vehicle strongly depends on the specifics of the propulsion system and its position relative to the other components. The purpose of paper is this factor can be characterized by changing several contributing parameters, such as distance from the ground, fuselage and wing as well as the nacelle outlet velocity and analyzing the aerodynamic performance. Design/methodology/approach Navier–Stokes equations are discretized in space using finite volume method. A KW-SST model is implemented to model the turbulence. The flow is assumed steady, single-phase, viscous, Newtonian and compressible. Accordingly, after validation and verification against experimental and numerical results of DLRF6 configuration, the location of the propulsion system relative to configuration body is examined. Findings At the nacelle outlet velocity of V/Vinf = 4, the optimal location identified in this study delivers 16% larger lift to drag ratio compared to the baseline configuration. Practical implications Altering the position of the propulsion system along the longitudinal direction does not have a noticeable effect on the vehicle performance. Originality/value Aerial vehicles including wing-in-ground effect vehicles require thrust to fly. Generating this necessary thrust for motion and acceleration is thoroughly affected by the vehicle aerodynamics. There is a lack of rigorous understanding of such topics owing to the immaturity of science in this area. Complexity and diversity of performance variables for a numerical solution and finding a logical connection between these parameters are among the related challenges.
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Peters, Brett y Mesbah Uddin. "Impact of Longitudinal Acceleration and Deceleration on Bluff Body Wakes". Fluids 4, n.º 3 (18 de agosto de 2019): 158. http://dx.doi.org/10.3390/fluids4030158.
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This study investigated the unsteady acceleration aerodynamics of bluff bodies through the study of a channel mounted square cylinder undergoing free-stream acceleration of ± 20 m / s 2 with Reynolds numbers spanning 3.2e4 to 3.6e5. To achieve this, a numerical simulation was created with a commercial finite volume unstructured computational fluid dynamics code, which was first validated using Improved Delayed Detached Eddy Simulation against experimental and direct numerical simulated results. Then, the free stream conditions were subjected to a periodic velocity signal where data were recorded and ensemble averaged over at least 30 distinct acceleration and deceleration data points. This enabled the comparison of body forces and flow field variations among accelerating, steady and decelerating free-stream conditions. Body force analysis determined that decelerating and accelerating drag forces varied −47% and 44%, respectively, in comparison to steady free-stream conditions. In addition, several differences were also observed and explored such as near-body flow structures, wake dynamics, Kármán vortices and vorticity production during the aforementioned conditions. The primary interest of this study was for the future application towards road vehicles for predictive dynamic modeling and aerodynamic development.
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Nguyen, N. V., J. W. Lee, M. Tyan y D. Lee. "Possibility-Based Multidisciplinary Optimisation For Electric-Powered Unmanned Aerial Vehicle Design". Aeronautical Journal 119, n.º 1221 (noviembre de 2015): 1397–414. http://dx.doi.org/10.1017/s0001924000011313.
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AbstractThis paper describes a possibility-based multidisciplinary optimisation for electric-powered unmanned aerial vehicles (UAVs) design. An in-house integrated UAV (iUAV) analysis program that uses an electric-powered motor was developed and validated by a Predator A configuration for aerodynamics, weight, and performance parameters. An electric-powered propulsion system was proposed to replace a piston engine and fuel with an electric motor, power controllers, and battery from an eco-system point of view. Moreover, an in-house Possibility-Based Design Optimisation (iPBDO) solver was researched and developed to effectively handle uncertainty variables and parameters and to further shift constraints into a feasible design space. A sensitivity analysis was performed to reduce the dimensions of design variables and the computational load during the iPBDO process. Maximising the electric-powered UAV endurance while solving the iPBDO yields more conservative, but more reliable, optimal UAV configuration results than the traditional deterministic optimisation approach. A high fidelity analysis was used to demonstrate the effectiveness of the process by verifying the accuracy of the optimal electric-powered UAV configuration at two possibility index values and a baseline.