Papers by Keyword: Aerodynamics

Abstract: The usage of unmanned aerial vehicles has grown drastically because of their ability to operate in dangerous locations while keeping their human operators at a safe distance. In the present work, an attempt has been made to design and fabricate a quadcopter for video surveillance. For continuous video streaming, a miniature wireless camera has been installed in the quadcopter. The camera helps the user to guide the vehicle and also to receive continuous clips of the surveyed location in laptop. Further analysis has been carried out on the frame material to determine better feasible option for carrying out the fabrication. The control system consists of a RC joystick, which sends the input to the multi rotor board using transmitter and receiver. KK 2.1.5 board is used as the brain of the device. Since quadcopter has a better dynamic stability than helicopter, giving the user more comfort of flying, they play a predominant role in different areas for surveillance, military operations, fire sensing and many other complex situations.

Abstract: This article will present a morphing wing actuated using both surface embedded Shape memory alloys (SMAs) and trailing edge Macro-fiber composites (MFCs). This combination enables the airfoil to simultaneously achieve large scale deformations at low frequencies as well as rapid actuation with a limited amount of displacement. Thereby not only can the shape of the airfoil be optimized in function of the current mission profile but also the shear layer can be influenced. Each actuator is modelled using both a finite element and/or an analytical model and the results will be verified experimentally.

Abstract: In this paper it is presented the design optimization of the rear wing of a sports car. The wing profile was parameterized with three variables, the angle of attack was the fourth variable and the objective function was to minimize the lift over drag ratio. Three virtual models were considered: a model without rear wing, a model with a rear wing with initial profile and position and a model with optimized rear wing. For these three models the drag and lift coefficients were calculated for comparison along with drag and lift forces.

Abstract: Ultra-high speed grinding (UHSG) is a significant and promising machining technology in grinding hard-to-cut materials. To find out the aerodynamics of the grinding wheel body when the airflow field has subsonic, transonic, and supersonic speed characteristics and clarify the corresponding influence on the grinding mechanism, the study is conducted to develop a supersonic grinding machine tool that is capable of being operated at extreme wheel speed up to 450 m/s and meanwhile accompanying with high grinding capability. In accordance with the main design objectives, a high performance grinding motorized spindle with maximum rotational speed 36000r/min and maximum power 28kW is developed. The linear motor feed driven system is also exploited to satisfy the requirement of maximum reciprocating speed up to 2m/s. Following plenty of specific design and performance analysis works, a prototype of supersonic grinding machine tool is finally developed. In the end, this paper also puts forward a number of further studies and prospective for the research activities on basis of the developed grinder.

Abstract: In this article the issues related to Computional Fluid Dynamics of the occurrence of innovative aerodynamic effect were presented. Analysis were performed to determine the occurrence of Kammback aerodynamic effect and its application in a shape of a body of the real racing car in order to minimize drag forces of the vehicle. For the analysis, ideal aerodynamic shapes were modeled, subsequently they were subjected to modifications which were used to determine the occurrence of effect. The basic modeled shape was the raindrop shape solid, which is generally regarded as the ideal shape in terms of aerodynamics. The result of analysis was compared with the drag values known from the literature. Afterwards changes in the shape of the base solid were made to verify and determine the optimum Kammback shape, selected from a set of possible solutions, in which the geometrical changes has the lowest difference of values of drag force and drag coefficient Cx(Cd) in comparison to the basic raindrop shape. Results of the study were subjected to graphic analysis, especially the distribution of air pressure on the surface of a solid and in a virtual wind tunnel, distribution of the air velocity and the course of air streams around the shape. The results were used to design the body of electric race car. The main objective was to minimize the aerodynamic drag of the vehicle.

Abstract: In this work improvements on the geometry of a high aspect ratio aircraft wing are studied, in order to reduce the wing in-flight deformation, without changing the drag of the aircraft and without increasing the structural weight. For this, from a reference rectangular wing, one new wing with elliptical planform has been defined; and comparative analyses of loads and structural deformation have been made for the wings considered: the original rectangular wing and the new corresponding elliptical wing. The aerodynamic analysis is based on the lifting line approach. A computer routine is made by the authors based on this approach, to obtain both induced drag values and the load distribution of the two wings, the original one and the corresponding elliptical. Based on the loads, spars for the two wings have been defined, and in order to evaluate the vertical displacements in flight, a finite element routine have been used. The main result of this study is the comparison of the deformation of wings considered, subjected to the same load factor, and for the same aircraft mass. The results obtained are encouraging for further developments using the present methodology.

Abstract: The prescribed surface curvature distribution blade design (CIRCLE) method optimises aerofoils and blades by controlling curvature continuity and slope of curvature distribution along their surfaces. The symmetrical NACA0012 exhibits a surface curvature discontinuity at the leading edge point, and the non-symmetrical E387 exhibits slope-of-curvature discontinuities in the surface. The CIRCLE method is applied to both aerofoils to remove both surface curvature and slope-of-curvature discontinuities. Computational fluid dynamics analyses are used to investigate the curvature effects on aerodynamic performance of the original and modified aerofoils. These results are compared with experimental data obtained from tests on the original aerofoil geometry. The computed aerodynamic advantages of the modified aerofoil are analysed in different operating conditions. The leading edge singularity of NACA0012 is removed and it is shown that the surface curvature discontinuity affects the aerodynamic performance near the stalling angle of attack. The discontinuous slope-of-curvature distribution of E387 influences the size of the laminar separation bubble at lower Reynolds numbers, and it affects the inherent profile of the aerofoil at higher Reynolds numbers. It is concluded that the surface curvature distribution of aerofoils has a significant effect on aerofoil aerodynamic performance, which can be improved by redesigning the surface curvature distribution of the original aerofoil geometry.

Abstract: The boiler KE-10-14 reconstructed under high-temperature furnace circulation fluidized bed has been considered. Features of the boiler with a high-temperature furnace circulation fluidized bed have been presented. The characteristics of the boiler and problem of its operation for the whole period of operation have been shown. Recommendations for improving the efficiency of boiler have been developed on the basis of conducted operational tests. The results of adjustment system sectional blast have been presented. The characteristics of the boiler on different types of coal have been compared. The application of HTCFB furnace as well as carry out commissioning activities has made it possible to increase the effectiveness of the KE-10-14 boiler.

Abstract: The article describes the study of turbulent characteristics in the enclosed chamber of a rectangular corss-section nozzle using numerical calculations. Suitable Ansys Fluent software models were selected based on the measurements results comparison in an aerodynamic tunnel as the fluid exits the nozzle. Special attention is paid to profile velocity near the peripheral wall of the observed enclosed chamber in order to confirm the optimal shape of the contraction and thus take steps towards a high quality velocity field.

Abstract: The human powered vehicle market is not only a larger market per unit than the automotive market, but it is one in growth. The main product of this market is the classical bicycle, which is familiar around the globe, but mainly in the urban environment. The bicycle, which in this paper will be considered a human powered vehicle, is slowly gaining ground in the field of urban transportation solutions. This paper analyzes the possibility of optimizing the body of a human powered vehicle recumbent tricycle through continuous fluid dynamics. The vehicle is already designed and built, and is fully functional. The body of the vehicle comes as a necessity to give the operator protection from the elements, but the main reason is, to give the vehicle less air resistance. This would be a great benefit to the operator and the perceived comfort. Usually the aerodynamics analysis comprise of a wind tunnel test that confirms the theoretical results. This paper shows the evolution of the body of a human powered vehicle as it is optimized after identifying the turbulent areas in its shapes. After optimization, a body is obtained which will be proposed for implementing over the built vehicle.