• Title/Summary/Keyword: Rear-spoiler

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Experimental Study on Drag Reduction of Ground Vehicle Using a Rear-Spoiler (Rear-spoiler를 이용한 자동차의 항력감소에 관한 실험적 연구)

  • 최재호;이상준
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.3
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    • pp.31-39
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    • 1996
  • The effect of rear-spoiler attached at rear end of automobile trunk on the aerodynamic characteristics of a MIRA reference car model was experimentally investigated. For different shapes and positions(G/H) of the rear-spoiler, the aerodynamic forces on the automobile were measured at various flow speed(ReL). The effect of rear-spoiler on the wake structure behind the automobile was also investigated using flow visualization and hot-wire anemometer. The rear-spoiler modifies the near wake structure and decreases aerodynamic drag and increases driving stability compared with those of the conventional automobile without rear-spoiler. From the experimental results, rear-spoiler of airfoil shape installed at the position of G/H=0.084 shows the best aerodynamic performance.

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Influence of a rear spoiler on a squareback car wake (리어 스포일러 장착에 의한 자동차 후류의 변화 연구)

  • Baek, Seung-Jin;Oh, Min-Soo;Lee, Jung-Ho;Kim, Moo-Sang
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1825-1829
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    • 2004
  • A numerical simulation was performed of flow behind a squareback car with a rear spoiler. Influence of the rear spoiler on drag force has been studied. A lattice Boltzmann method was utilized to portray the unsteady aerodynamics of wake flows. The pressure distributions were employed to examine the vortex formation mode against the rear spoiler. It was found that the separation flow at roof end and c-pillar makes three dimensional vortex structures and the rear spoiler increases pressure on the rear glass surface.

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A Numerical Investigation on the Wake Flow Characteristics and Rear-Spoiler Effect of a Large-Sized Bus Body (대형버스 바디모델의 후류특성 및 후미 스포일러 효과에 관한 해석적 고찰)

  • 김민호;국종영;천인범
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.2
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    • pp.126-133
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    • 2003
  • The aerodynamic characteristics of automobiles have received substantial interest recently. Detailed knowledge of the vehicle aerodynamics is essential to improve fuel efficiency and enhance stability at high-speed cruising. In this study, a numerical simulation has been carried out for three-dimensional turbulent flows around a commercial bus body. Also, the effect of rear-spoiler attached at rear end of bus body was investigated. The Wavier-Stokes equation is solved with SIMPLE method in general curvilinear coordinates system. RNG $k-\varepsilon$ turbulence model with the MARS scheme was used for the evaluating aerodynamic forces, velocity and pressure distribution. The results showed details of the three-dimensional wake flow in the immediate rear of bus body and the effect of rear-spoiler on the wake structure. A maximum of 14% reduction in drag coefficient was achieved for a model with a rear-spoiler.

A Study on the Optimum Design of SUV Rear Spoiler (SUV 차량 리어 스포일러 최적 형상에 관한 연구)

  • Park, Dong-Kyou
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.2
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    • pp.689-694
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    • 2018
  • Recently, fuel consumption efficiency has become the most important issue in the vehicle development process due to the problem of environmental pollution. The air flow patterns of the vehicle body line and rear part are the most important elements affecting the fuel consumption efficiency. Especially, the airflow pattern of the vehicle rear part is the most important design factor to be considered in rear spoiler design. In this paper, the control factors affecting the airflow of the rear spoiler are determined, the airflow sensitivity of these control factors are tested and, then, the optimized control factors to reduce the airflow drag force are proposed. The model of optimized control factors is tested and the values of the optimized control factors are changed by analyzing the S/N ratio and mean value. Finally, the new modified model incorporating the optimized control factors is tested in an air flow tunnel and its ability to decrease the air drag and reduce the cost is verified.

An Experimental Study on the Aerodynamic Characteristics of a Streamline-designed High-speed Bus (유선형 고속주행 버스의 공력특성에 관한 실험 연구)

  • Kim, Chul-Ho;Lee, Seung-Hyun
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.2
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    • pp.198-204
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    • 2016
  • In this study, a wind tunnel test was conducted to measure the aerodynamic characteristics of a streamline-designed high-speed bus with the change of wind direction and speed and the result is compared with the aerodynamic performance of a commercialized high-speed bus model (Model-0) manufactured by Zyle Daewoo Bus Corp. Aerodynamic performance of the existing rear-spoiler was tested to prove its aerodynamic effect on the test model bus. From the study, it was found that 24.6 % of the total drag of the original bus model (Model-0) was reduced on the streamline-designed model bus(model-1) without the rear-spoiler but only 14.3 % of the total drag was reduced with the spoiler on the streamlined model bus. It means that the rear spoiler does not work properly with the streamlined model bus (model-1) and should be noted that an optimum design of a rear-spoiler of a vehicle is important to reduce the induced pressure drag and increase the driving stability of a vehicle against yaw motion. The experimental outcome was also compared to the previous numerical research result to evaluate the reliability of the numerical algorithm of the aerodynamic performance analysis of a vehicle. The error rate (%) of the numerical result to the experimental output is about 5.4 % and it is due to the simplified body configuration of the numerical model bus. The drag increases at the higher yaw angle because the transparent frontal area of the model vehicle increases and the downward force increases with the yaw angle as well. It has a positive effect to the driving stability of the vehicle but the moderated downward force should be kept for the fuel economy of a vehicle.

Experimental Study on the Aerodynamic Characteristics of a Passenger Vehicle with Winglets (윙렛을 부착한 승용차의 공력특성에 관한 실험적 연구)

  • 임진혁
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.7
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    • pp.149-156
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    • 1999
  • In this study, aerodynmaic characteristics of the notch-back and fast-backpassenger vehicle models(1/10~1/12 acale) attached with winglets were experimentally investigated in a low speed wind tunnel. For various positions(X/L). tilted angles($\beta$) of a winglet, the aerodynamic forces on the vehicle model and rear-surface pressures were measured at various flow speeds. Also a flow of model surface was visualized by tuft method. The experimental results showed that winglets effect aerodynamic characteristics of vehicle models. A maximum of 3% reduction in lift coefficient was achieved with winglets at $\alpha$=-30$^{\circ}$. A maximum of 10% reduction in drag coefficient was achieved for a model with winglets and a rear-spoiler.

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A Numerical Study on the Flow around Automobile (자동차 주위의 유동에 관한 수치해석적 연구)

  • 진원재
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.555-558
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    • 2000
  • Conventional aerodynamic simulations have carried out by using Supercomputer and over a hundred grid point or wind tunnel experiment. It takes s long time to get a result. This paper has dealt on flow characteristics of automobile in the flow field. CFD(Computational Fluid Dynamics) has been able to apply to industrial field in these days. This new method has been applied to the aerodynamic simulation system, a designer has been able to carry out the practical on early designing phase of automobile. This paper has been focused on the necessity of rear-spoiler, the peculiarity of aerodynamic drag, and the level of drive safety.

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Wind Deflector Design of Spoiler Sunroof by Boundary Theory (경계층 이론에 의한 스포일러 선루프의 윈드 디플렉터 설계)

  • Cho, Hyun-Deog
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.5 no.3
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    • pp.17-22
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    • 2006
  • Sunroof is getting widely used in automobiles since it maintains, compare to window, better air circulation as well as less noise while driving in high speed. In this study, we consider an electronic control type spoiler sunroof which slides backward after tilting a rear part of a glass. Installing a wind deflector on the sunroof reduces noise much more effectively. The height of the wind deflector is designed using a boundary theory related to incompressible air layer. The developed wind deflector is investigated experimentally by measuring a wind noise. When the height of the wind deflector is designed by a fixed type, the sunroof maintains a very quiet interior noise over a certain driving speed, nevertheless it produces relatively loud noise in low driving speed.

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Flow Analysis according to the Installation of an Aero Part in a Sports Car (스포츠카의 에어로 파츠 설치에 따른 유동해석)

  • Choi, Kyekwang;Cho, Jaeung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.1
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    • pp.36-42
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    • 2020
  • In this study, flow analyses of a vehicle at driving were carried out after each installation of a tuning part, specifically the bonnet air ducts, the rear spoiler, and the rear diffuser. The study models were designed to comprise a total of eight cases in which each of the three parts were mounted individually or all together in vehicles. Assuming that the vehicle were driven with an average high speed of 100 km/h, the speed and pressure around the vehicle were obtained using CFD when driving. The rear diffuser that becomes the most effective among the three mounting parts has a major role in reducing air resistance.