Papers by Keyword: Aerodynamic Drag

Abstract: In order to increase the driving range of electric vehicles, a lift-drag hybrid vertical axis wind turbine (VAWT) and an air duct were designed in this paper, which could realize the wind energy recovering. The energy conversion theory of the concentrated wind energy was introduced into the design of air duct. The wind speed would be increased by 30% after concentrated by the air duct which was verified through CFX simulation. The simulation of original vehicle model, wind turbine and air duct were carried out respectively in Ansys Workbench. And after adding the wind energy recovery device, the drag resistance coefficient of the electric vehicle is reduced by about 8.84%. Indoor laboratory tests conducted on a scale-up model show the flow fields inside the air duct and the turbine rotational speeds in different wind conditions. Results show that position 3 is the optimal matching position of wind turbine and air duct where the cut-in speed is about 4.78km/h and the maximum rotational speed of wind turbine is 458rpm.

Abstract: The pressure drag of the vehicle has a significant impact on its energy consumption. The aerodynamic drag has become a prevalent among the other components of the motion resistance forces with the speed increasing above a certain value. Therefore, it is necessary to refine the value vehicles’ aerodynamic drag in a real-city-traffic condition.

Abstract: With reference to a certain type of flying drones with imitation airfoil design a seagull flat wings and on the basis of its wing tip winglet in this paper. Through to the numerical simulation of two wings, it is concluded that the bionic wing aerodynamic performance is superior to the conventional airfoil wing, after adding wing tip winglet bionic wings effectively reduced the downwash velocity, reduce the induced drag, makes the wing aerodynamic performance is improved. Provide theoretical reference for the design of the uav wing

Abstract: Multiple schemes are adapted on truck's outer flow field based on numerical simulation. Comparative analysis with the state of air flow, the pressure distribution, the air movement between the cab and cargo is pursued, then obtain the effect of jet flow velocity to the truck Cd. With the increasing of the jet velocity, Cd increases first and then decreases. The maximum drag reduction can reaches 7.38%.

Abstract: The current Jilin University’s energy-saving car has two problems.Firstly,long time driving let the driver get a pain in the neck,which is uncomfortable. Secondly,the low overheight of the carbody result in a bad vision. This paper try to show how we solve these problems. In order to ease the neck pain and better the vision, the driving space should be increased,which may result in the grow of aerodynamic drag.That’s not welcome. So as to realize the relative balance between driving comfort and aerodynamic drag of energy-saving car. Our group consider the relationship between these two factors, make a wooden model to get the feedback about the actual feeling and calculate the aerodynamic drag by using analysis softwares. Finally,we got a better design plan which satisfied both the aerodynamic drag and driving comfort. The new design plan not only bring energy-saving car’s driving more comfortable,but let us accumulate lots of design experience of energy-saving car.

Abstract: Aerodynamic drag is one of the most important sources of the driving resistance suffered by an on-road heavy-duty truck. The previous studies have rarely involved the role of the external sun visor. Therefore, numerical method is used for the research of the influence of six kinds of sun visors differenced by shapes or layouts on the aerodynamic drag reduction. It is demonstrated that the sun visor has a great influence on the local flow field where it is fixed, while a relatively small effect on the global flow field. Moreover, compared to the original one, the C_D values of each case have different degrees of reduction which illustrates that an appropriate shape and layout of a sun visor benefits the air drag reduction, the largest decline is 4.7%.

Abstract: The principles and method of computational fluid dynamics were applied to numerical simulate the external flow field about the SUV model. The hybrid mesh of tetrahedral and triangular prismatic as well as the turbulence model of Realizable k-ε was adopted to study the flow field of SUV of flat underground. Then the SUV of complex underground was simulated with the same mesh strategy and boundary condition. The aerodynamic drag coefficient of latter was bigger than former. That illuminated the complex underground has affect to aerodynamic performance of vehicle. The wind tunnel test validated the veracity of numerical simulation. Based on that, the underground cover board was appended; the aerodynamic drag coefficient was depressed. The velocity and pressure distribution and flow line were achieved. The conclusions provide theoretical reference for the further study of aerodynamic drag reduction of complex underground.

Abstract: This paper focuses on a new method of aerodynamic drag reduction. In this paper numerical simulation method is adopted to investigate the relationship between the aerodynamic drag characteristics of a blunt body and the distribution of total pressure around the body. The study shows that when the shape of a blunt body is modified to be close to its isobaric surface, the pressure drag of the body can be reduced largely while the viscous drag increases slightly, and the summary of the drag gets lower as a result. This conclusion will have profound guiding significance in the aerodynamic shape designing and the aerodynamic drag reduction of an automobile.

Abstract: Because of reducing aerodynamic drag, the maglev train could run at a high-speed in the partial vacuum tube. Scientists of some conutries such as U.S., Swiss and China, have started the research work on high-speed tube trains. In this situation, evacuated tube transportation aerodynamics becomes an important theory research aspect, in which the main study content is how to calculate aerodynamic drag. Based on the explicit formula for estimating aerodynamic drag on moving body in an infinite boundary surroundings put up by Isaac Newton, the evacuated tube surroundings is analyzed and the explicit formula with blockage ratio as an independent variable for estimating aerodynamic drag acted on trains running in the evacuated tube which is a finite space is deduced. With the calculation case, compared with the results came out from the explicit formula got in this paper and the results got by Fluent software, it was found that those results are closed. Thus, the explicit formula created in this paper for conveniently estimating aerodynamic drag based on trains running in evacuated tube transportation is credible.

Abstract: The influence of different truck structure parameters on the aerodynamic drag is studied. Saving energy and reducing emissions are two worldwide issues. Decreasing aerodynamic drag for the truck becomes more and more important, which is investigated in this paper based on the CFD method. Three structure parameters of a real truck model are studied, including the height difference between the cab fairing and the trailer, the gap between the cab and the trailer, the angle at the bottom of the truck tail. Their impact on the flow field, pressure and drag are investigated. The results show that there is complicated nonlinear relationship between the structure parameter and the aerodynamic drag. A comprehensive optimization of those parameters can effectively reduce the aerodynamic drag. In this paper a 15% decrease of aerodynamic drag is observed by optimization.