Papers by Keyword: Aerodynamics

Abstract: Aerodynamics contributed directly on the energy efficiency and fuel consumption reduction of heavy vehicles in addition to its stability. The present study examines numerically the aerodynamics of heavy vehicles considering different drag-reduction devices using SolidWorks programme. Four different drag-reduction devices such as Base flaps, filled boat tail, Deflector and Rear offset plate in order to compare them with the baseline model. the results showed that the reflector contribute in more drag formation while Rear offset plate leads to lower drag.

Abstract: This paper focuses on the design and construction of the front wing for the FS TUL Racing team's monopost, which competes in Formula Student racing. The aim is to use knowledge of fluid mechanics, structural design, materials, CAD systems and CFD simulations to optimise the aerodynamic properties of the vehicle. The thesis explores the basic principles of aerodynamics and analyses the problems encountered in the design process. It includes testing of carbon fabrics and subsequent selection of the most appropriate material for the application. The research also includes the development and comparison of three wing variants using CFD simulations, with subsequent evaluation of the selected variant in the wind tunnel. The result is the selection of the optimum wing variant that meets the specified performance and safety requirements. This variant is then compared with the CAD model using 3D scanning to verify its accuracy and quality. The work contributes to the advancement of the field of race car aerodynamics and provides valuable insights for future development teams, thus supporting further technology development in motorsport.

Abstract: The development of drag and lift balance aimed to modify and creating a measuring instrument that may be used in the field of aerodynamics or in testing aerodynamic properties. This measurement is in the form of wind speed on an object model such as airfoils, building models and automotive technology. This design uses an open circuit wind tunnel with a low turbulence subsonic type, with a maximum air speed of 30 m/s. The exsisting wind tunnel still uses an analogue measuring instrument which is then modify in a digital arduino-based for drag and lift balance measuring instrument with a drag and lift sensor maximum load of 1kg (v=30m/s) and maximum air speed of 50m/s. The Measuring instrument is calibrated using a 1kg weight test equipment for testing with the test object model (spherical, hemispherical, cylindrical, cube) and three types of airfoil models. The test results are in the form of drag coefficient (C_d) and lift coefficient (C_L). The coefficient of drag is greatest in the cube shape and lowest in the sphere, but will decrease in value at a speed of 20 m/s. In the airfoil, the values ​​of C_d and C_L have the same trend with the literature with an uncertainty value of less than 10%. The value of C_L / C_d will increase as the angle of attack increases, but can very significantly depending on the fluid, airfoil, and aircraft type.

Abstract: In this paper, a numerical study of fluid flow through perforated panels with square holes and open-cell material with cubic cells is presented. Structures with a wide variety of porosities (0.15<φ<0.94) and Reynolds numbers (0.01<Re<6000) are studied. Among the various outcomes obtained, the results indicate that pressure gradient vs Reynolds number exhibits three different forms of variation, including linear (Re<1), nonlinear (1≤Re<4000), and one where the pressure gradient is virtually constant with the Reynolds number (Re≥4000). The results were provided in terms of loss factor, but also of intrinsic permeability and the Forchheimer coefficient. Relationships that connect porosity to the loss factor, intrinsic permeability, and Forchheimer coefficient are also presented. These findings may prove useful in better understanding the flow behaviors in perforated panels and cell metal foams, which have a wide range of applications.

Abstract: 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.

Abstract: The growing demand for energy efficiency gains in vehicles has led to several advances in more technological and efficient driving units, projects using lighter and more resistant materials and, in particular, a deeper study of aerodynamic studies in order to understand the fluid flow around the object of study. This work presents an aerodynamic study for a vehicle of high-energy efficiency, through computational fluid dynamics simulation in Ansys Fluent software. The main objective is to obtain the traction and drag force vectors acting on the vehicle at different speeds and to better understand the airflow before, during and after contact with the vehicle. With the possession of results, it was facilitated the implementation of improvements that enabled the vehicle to operate even more efficiently.

Abstract: 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.

Abstract: The article deals with the use of renewable energy sources in construction in general and in high-rise unique buildings. Such approach will allow to design and construct buildings in which integrated renewable energy sources can be perfectly applied to all aspects of construction. The historical development of architecture and ecology as a single phenomenon is considered. This is particularly relevant to high-rise buildings. With the implementation of energy-efficient technologies, the main drawback - high-energy consumption - will be cut off. The article raises the question of the need to merge these two concepts. Examples of buildings with applied renewable energy sources, both constructed and projected, are considered. Non-traditional energy sources such as wind, solar, land, water and biomass are analyzed. The relevance of their application in construction and influence on all aspects of the project is proved: town-planning, functional, space planning, architectural and artistic, constructive and engineering.

Abstract: Amongst current aircraft research topics, morphing wing is of great interest for improving the aerodynamic performance. A morphing wing prototype has been designed for wind tunnel experiments. The rear part of the wing - corresponding to the retracted flap - is actuated via a hybrid actuation system using both low frequency camber control and a high frequency vibrating trailing edge. The camber is modified via surface embedded shape memory alloys. The trailing edge vibrates thanks to piezoelectric macro-fiber composites. The actuated camber, amplitude and frequency ranges are characterized. To accurately control the camber, six independent shape memory alloy wires are controlled through nested closed-loops. A significant reduction in power consumption is possible via this control strategy. The effects on flow via morphing have been measured during wind tunnel experiments. This low scale mock-up aims to demonstrate the hybrid morphing concept, according to actuator capabilities point of view as well as aerodynamic performance.

Abstract: 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.