Aerodynamic drag reduction pdf

Aerodynamic drag reduction investigation for a simplified road vehicle using plasma flow control. Reducing aerodynamic drag and fuel consumption year 2002 statistics for combination trucks tractortrailers on nations highways 2. Research on aerodynamic drag reduction by vortex generators masaru koike tsunehisa nagayoshi naoki hamamoto abstract one of the main causes of aerodynamic drag for sedan vehicles is the separation of flow near the vehicles rear end. Computational characterization of drag reduction for. The incorporation of these devices requires proper choices of the size. In cold canadian climates, the aerodynamic drag in winter can be nearly 20% greater than at. Vehicle power consumption reduction can be achieved by various means such as improved engine efficiency and aerodynamic drag reduction. Paper open access numerical study on aerodynamic drag.

This study uses computational fluid dynamics to analyze the aerodynamic properties of multiple heavy vehicle groups in leaderfollower con gurations, referred to as platoons. Promising aerodynamic technologies for drag reduction are discussed, such as laminar flow control and lateral wing camber. The aerodynamic drag coefficients for the projectiles with inert motors are presented as a function of mach number and for the projectiles with live motors base drag reduction factors are presented as a function of time of flight. Aerodynamic drag reduction and flow control of ahmed body. Simple and lowcost aerodynamic drag reduction devices. The present work was also influenced by an interest in truck aerodynamic drag reduction. Aerodynamic drag reduction of opentop coal cars in unit train operation and impact on train fuel consumption and economics james paul, p. In aerodynamics, aerodynamic drag is the fluid drag force that acts on any moving solid body in the direction of the fluid freestream flow. Optimization of the aerodynamic drag reduction of a. The device is secured to the underside of the trailer so that the rearward end of the device is positioned just forwardly of the forward end of the rear wheel assembly of the trailer. Provided is an aerodynamic drag reduction apparatus for reducing aerodynamic drag on an overtheroad vehicle while underway.

The two vehicles collectively have less drag than the two in isolation. The primary metric of interest is the resistive aerodynamic force experienced in the. This drag reduction goal corresponds to a reduction in the tractortrailer truck drag coefficient from 0. Aerodynamic drag reduction of opentop coal cars in unit. Aerodynamic analysis of drag reduction devices on the underbody. In one embodiment, the device is coupled to the slider axle of the. Aerodynamic drag reduction technologies testing of heavy. Recent spikes in fuel prices and concern regarding greenhouse gas emissions, automotive design engineers are faced with the immediate task of introducing more efficient aerodynamic designs vehicles. Introduction aerodynamic drag is crucial for a vehicles mileage especially at high speeds as it increases in proportion to the square of the vehicle velocity1. This can be regarded as a decrease in drag coefficient. Due to higher price, limited supply and negative impacts on environment by fossil fuel, automobile industries have directed their concentrations in reducing the fuel consumption of vehicles in order to achieve the lower aerodynamic drag. Aerodynamic drag reduction by plasma and hotgas injection. For passenger cars the aerodynamic drag force is the dominating resistance force at higher velocity. Aerodynamic drag reduction investigation for a simplified.

Department of energy workshop on heavy vehicle aerodynamic drag and was cosponsored by the u. About 30% to 40% of the total fuel energy is lost to overcome road resistance, about 10% to 20% for operating electrical appliances and 50% to 60% to overcome the drag force. Also if the gap between rear screen and rear wall of the vehicle is increased, it can give better results in drag reduction. Aerodynamic drag d depends on the size of a vehicle projected frontal area, a, the drag coefficient cd which is a measure of the flow quality nearby the vehicle, and the square of the vehicle speed v as expressed in eq. The actuation is performed with pulsed jets at trailing edges and the flow is monitored with 16 pressure sensors distributed at the rear side. The overall reduction in aerodynamic drag force is 10%. Proceedings of the asme 2016 fluids engineering division summer meeting collocated with the asme 2016 heat transfer summer conference and the asme 2016 14th international conference on nanochannels, microchannels, and minichannels.

The major challenge among a number of design requirements for hypersonic vehicles is the reduction of drag and aerodynamic heating. Aerodynamic drag reduction an overview sciencedirect. In these techniques many attempts have been made since the early years in the automotive industry to reduce aerodynamic drag in order to improve performance and fuel economy. Reducing the aerodynamic drag offers an inexpensive solution to improve fuel efficiency and thus shape optimization for low drag become an essential part of the. The stateoftheart in aircraft drag prediction was defined as of 1973 by the agard conference entitled aerodynamic drag. A dragreducing aerospike is a device see nose cone design used to reduce the forebody pressure aerodynamic drag of blunt bodies at supersonic speeds. Investigation and recent developments in aerodynamic heating and drag reduction for hypersonic flows 23 july 2018 heat and mass transfer, vol. In addition to the aerodynamic drag reduction testing and analysis presented in this report, a series of tests examining the relationship between snap acceleration exhaust opacity. Numerical simulation, feedback flow control, vehicle, drag reduction, vortex shedding, pressure drag 1. So reducing of aerodynamic drag has become the primary concern in. Research on aerodynamic drag reduction by vortex generators. This work proposes an effective numerical model using the computational fluid dynamics cfd to obtain the flow structure around a passenger car with different addon devices.

Aerodynamic drag reduction technologies springerlink. Aerodynamic drag reduction for a generic truck using. The aerospike creates a detached shock ahead of the body. Methods for reducing aerodynamic drag in vehicles and thus. Review of research on vehicles aerodynamic drag reduction. Thus, the drag reduction program is one of the most interesting approaches to cater this matter. Aerodynamic drag reduction technologies proceedings of. To delay flow separation, bumpshaped vortex generators are tested for application to the roof end of a sedan. Pdf aerodynamic drag reduction of a squareback car. A numerical analysis of heterogeneous and homogeneous. Ga aerodynamic drag equivalent diameter, 14a mechanical drag rolling resistance coefficient local acceleration due to gravity. Exhaust gas redirecting towards the low pressure zone at the rear of the car is proved to be effective tosome extent, which paves the way of future improvement for future researchers. Simulations indicate an overall reduction in the aerodynamic drag coefficient of up to 18% for the bus and suv models with the use of the lateral guide vanes. The thesis aims to develop effective active flow control strategies for aerodynamic drag reduction of road vehicles.

From the early days, the designers recognized the importance of drag reduction and tried to streamlined the design. A fluidic oscillator is a simple device that converts a. The focus of this experimental study is drag reduction on an ahmed body vehicle analogue using a variety of configurations involving fluidic oscillators to promote attachment and reduce wake size. Produced under direction of california air resources board carb by the. For heavyduty vehicles, such as tractortrailer combinations, the drag coefficient increases significantly with yaw angle. Numerical study on aerodynamic drag reduction and energy harvest for electric vehicle. Aerodynamics, drag reduction, fuel consumption, computational fluid dynamics, bus. Between the shock and the forebody a zone of recirculating flow occurs which acts like a more streamlined forebody profile, reducing the drag. Optimization of the aerodynamic drag reduction of a passenger hatchback car ziyu guo, yingchao zhang, and wei ding proceedings of the institution of mechanical engineers, part g. A method for the reduction of aerodynamic drag of road vehicles.

A reassessment of heavyduty truck aerodynamic design. Of all these techniques of drag and heat flux reduction. An examination of active drag reduction methods for ground. Department of energy and the lawrence livermore national laboratory. A simple method for estimating the maximum liftdrag ratio of a new design is derived from the skin friction drag of an equivalent flat plate, form drag and a statistical correction for distributed roughness. Numerical study on aerodynamic drag reduction of racing. The computationalnumerical model of the passenger car and mesh was constructed using ansys fluent which is the cfd solver and employed in the present work. Model 2 is to modify and analyze by using cfd to reduce the drag force, which results in increased performance and reduced the fuel requirement. To achieve the fuel economy goal, the aerodynamic drag of the vehicle would have to be reduced 30% at 60 mph. One of the popular methods of reducing the aerodynamic drag of non circular bluff bodies at subcritlcal. Drag reduction obtained by the addition of a boattail to a. International journal of engineering materials and manufacture 2019 41 1 14. This conference, succeeding the european fora on laminar flow technology 1992 and 1996, was initiated.

This conference, succeeding the european fora on laminar flow technology 1992 and 1996, was initiated by the european drag reduction network dragnet and organised by dglr under the auspice of ceas. An aerofoilbased roof design concept is shown to reduce the overall aerodynamic drag by up to 20% and an analysis of its effect on overall fuel. Reducing aerodynamic drag and rolling resistance from heavy. Conventionally, aerodynamic drag has been reduced by designing a. The continuous surge in gas prices has raised major concerns about vehicle fuel efficiency, and drag reduction devices offer a promising strategy. Review on the research performance of active and passive flow control on the vehicle aerodynamic drag reduction is reported in this paper. Cooper a wind tunnel investigation into the fuel savings available from the aerodynamic drag reduction of trucks. Aerodynamic drag reduction technologies testing of. This is increasingly being achieved by the platooning of multiple vehicles coupled with a controller to govern engine usage and preserve proper separation. Drag reduction of passenger car using addon devices.

Aerodynamic drag accounts for a sizable portion of transportation energy consumption. We experimentally examine the effects of fluidic actuation on the wake past a simplified squareback car model. A drag reduction device for a trailer comprising a generally ushaped upstanding wall means having a floor secured to the lower end thereof. Fundamental study of aerodynamic drag reduction for. Aerodynamic drag reduction by rear under body modification results in up to 22. The car body is often optimized for reducing the drag. Pdf due to higher price, limited supply and negative impacts on environment by fossil fuel, automobile industries have directed their. The aerodynamic drag reduction system includes a frame assembly that is adapted to cooperate with a cargocarrying portion of the overtheroad vehicle to couple the drag reduction apparatus to the overtheroad vehicle. Cfd analysis of aerodynamic drag reduction of automobile. Aerodynamic drag and its reduction advanced aircraft. Us8322778b1 aerodynamic drag reduction device for a. Aerodynamic drag of hgvs is usually reduced through a number of approaches including streamlining airflow 4, reducing the extent of wake. Aerodynamic drag reduction of emergency response vehicles. Furthermore, there are clear linkages between aerodynamic drag on a particular vehicle and that vehicles fuel economy, providing incentive to decrease drag and thus decrease fuel usage.

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