• Transactions of the Korean Society of Automotive Engineers
• /
• v.20 no.5
• /
• pp.26-35
• /
• 2012

This paper investigates the influence on the aerodynamic performance of a passenger cruising very fast by some specific car body parts such as side mirrors, wheel arches and wheels designed hardly regarding aerodynamics. The magnitude of the contribution of each part is analyzed via on the CFD simulations. YF SONATA, a sedan of Hyundai Motors Company, plays a major role as the baseline car in this research, representing all passenger car. The CFD analysis condition consists of 6 different cases depending on whether each part exists or not. According to the CFD results, there were confirmed that additionally to the body parts' own drag, the car body went through somewhat the consequential increment of the drag by them. Among the 3 parts, wheel is the magnate that not only has the maximal drag but drives the drag of the passenger car to increase most steeply and the next is the side mirror.

• Composites Research
• /
• v.32 no.5
• /
• pp.284-289
• /
• 2019

In the present paper, the dynamic force-moment equilibrium equations, driving power and energy equations are analyzed to formulate the equation for fuel economy(km/liter) equivalent to the driving distance (km) divided by the fuel volume (liter) of the vehicle, a selected model of gasoline powered KIA K3 (1.6v). In addition, the effects of the dynamic parameters such as speed of vehicle (V), vehicle total weight(M), rolling resistance ($C_r$) between tires and road surface, inclined angle of road (${\theta}$), as well as the aerodynamic parameters such as drag coefficient ($C_d$) of vehicle, air density(${\rho}$), cross-sectional area (A) of vehicle, wind speed ($V_w$) have been analyzed. And the possibility of alternative materials such as lightweight metal alloys, fiber reinforced plastic composite materials to replace the conventional steel and casting iron materials and to reduce the weight of the vehicle has been investigated by Ashby's material index method. Through studies, the following results were obtained. The most influencing parameters on the fuel economy at high speed zone (100 km/h) were V, the aerodynamic parameters such as $C_d$, A, ${\rho}$, and $C_r$ and M. While at low speed zone (60 km/h), they are, in magnitude order, dynamic parameters such as V, M, $C_r$ and aerodynamic ones such as $C_d$, A, and ${\rho}$, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.8
• /
• pp.2750-2757
• /
• 2010

Recently, there have been a number of voices from industry that automotive education at the college is too theoretical and so college graduates are lack of practical ability to apply the automotive idea to actual systems. In order to educate engineering students design qualities in creative problem solving, this paper reports the results of employing engineering design projects in a Motor sports course of at A College. This paper presents design creterion and manufacture process of $CO_2$ model dragster, measures $CO_2$ model dragster speed and aerodynamic drag. In order to investigate the impact of engineering design on student's learning, a survey was conducted in 2008 spring semester. According to the results of survey analyses, student's key competencies and satisfaction reports high values on engineering design projects.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.5
• /
• pp.100-107
• /
• 2010

This paper gives new conceptual descriptions of drag reduction mechanism owing to rotating wheel and moving ground condition when dealing with automotive aerodynamics. Using Computational Fluid Dynamics (CFD), flow simulation of three dimensional automobile configuration made by Vehicle Modeling Function (VMF) is performed and the influence of wheel arch, wheels, rotating wheel & moving ground condition to the automotive aerodynamic performance is analyzed. Finally, it is shown that rotating wheel & moving ground condition decreases automotive aerodynamic drag owing to the reduction of the induced drag led by the decrease of COANDA flow intensity of the rear trunk flow.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.2
• /
• pp.84-91
• /
• 2001

To investigate the aerodynamic characteristics of the on a road vehicle, experimenrs were performed at an Atmospheric Boundary Layer Wind Tunnel. The scaled model of an automobile with 1 : 3 scaling ratio was used. The Reynolds number based on the free stream velocity and model length was $7.93{\times}10^5$. The influence of crosswind to the stability of automobile was investigated by the pressure distribution measurements and flow visualization studies. with the variation of the angle of attack, the change in pressure coefficient depends highly on the flow separation regimes. The experimental and numerical results are compared and found to be in good agreements.

• 한국전산유체공학회:학술대회논문집
• /
• 2009.04a
• /
• pp.208-214
• /
• 2009

지하 복수층 주차장은 도시의 밀집화 및 자동차의 급격한 증가로 인한 토지부족 및 주차난을 해소할 수 있는 좋은 방법이다. 하지만 인체유해 배출가스의 집중으로 환기의 중요성이 대두되는 추세에도 불구하고 실제로는 시공이 완료 된 후에나 오염도 측정이 가능하다. 이러한 이유로 CFD 시뮬레이션으로 시공이전의 지하 복수층 주차장의 공기오염도를 예측했다. CFD 시뮬레이션은 예산과 시간을 절감한 공기오염도 예측이 가능하다. 실제의 당산근린공원의 지하주차장을 대상으로 오염도를 예측했다. 급기에만 강제유동을 일으키는 2종과 배기에만 강제유동을 일으키는 3종 기계환기법, 그리고 급배기에 강제유동을 일으키는 1종기계환기법을 각각 적용하여 공기오염도를 계산했다. 지하1층과 지하2층의 입구 및 출구유속을 10, 15m/s로 하여 실내평균연령과 실내평균환기효율을 살펴보았다. 계산결과는 급기와 배기에 강제유동을 동시에 일으키는 1종 기계환기법의 값과 비교하였다.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.24 no.3
• /
• pp.265-272
• /
• 2016

The objective of vehicle aerodynamic design is on the fuel economy, reduction of the harmful emission, minimizing the vibration and noise and the driving stability of the vehicle. Especially for a sedan, the driving stability of the vehicle is the main concern of the aerodynamic design of the vehicle indeed. In this theoretical study, an evaluation algorithm of aerodynamic driving stability of a vehicle was made to estimate the dynamic stability of a vehicle at the given driving condition on a road. For the stability evaluation of a driving vehicle, CFD simulation was conducted to have the rolling, pitching and yawing moments of a model vehicle and compared the values of the moments to the resistance moments. From the case study, it is found that a model sedan running at 100 km/h in speed on a straight level road is stable under the side wind with 45 m/s in speed. But the different results may be obtained on the buses and trucks because those vehicles have the wide side area. From the case study of the model vehicle moving on 100 km/h speed with 15 m/s side wind is evaluated using the numerical algorithm drawn from the study, the value of yawing moment is $608.6N{\cdot}m$, rolling moment $-641N{\cdot}m$ and pitching moment $3.9N{\cdot}m$. These values are smaller than each value of rotational resistance moment the model vehicle has, and therefore, the model vehicle's driving stability is guaranteed when driving 100 km/h with 15 m/s side wind.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1995.04a
• /
• pp.165-170
• /
• 1995

소음저감 설계기술은 제품의 경쟁력 향상을 위해 일반인이 쉽게 접근할 수 잇는 가전제품, 자동차, 항공기 분야 등에서 많은 연구가 수행되어 왔으며, 최근 소음환경 규제가 강화되고 대형기계의 설치 위치가 주거지역과 가까워지므로 산업용 기계설비의 소음제어에 대한 관심이 점차 증대되고 있다. 특히 디젤 엔진 발전기 세트를 이용해서 전원을 공급하는 산업용 기계에 있어서는 디젤 엔진과 발전기가 주소음원이며, 크게 기계적 소음, 공기 역학적 소음, 그리고 전자기 소음 등으로 분류된다. 본 연구는 이러한 소음을 발생시키는 엔진(Engine), 발전기(Generator), 방열팬(Radiator Fan) 등의 성능을 개선시켜 소음을 감소시키는 것이 아니라, 외부 덮개(Canopy)에 흡음재를 부착하여 소음저감 방법을 채택했다. 연구대상으로서는 항만에서 컨테이너(Container)를 운송하는 이동용 크레인(Transfer Crane)의 엔진 발전기 세트(set)로서, 각 구성품(엔진, 발전기, 방열 팬)의 음향 덮개의 내부구조를 설계하였다. 그리고 덮개 내부 온도를 일정하게 유지시키기 위하여 엔진에서 방사하는 방열공기와 내부로 흡입되는 냉각공기의 열유동장 해석도 병행하였다.

• Journal of Scientific & Technological Knowledge Infrastructure
• /
• s.6
• /
• pp.136-139
• /
• 2001

풍동과 같은 고가의 실험 장비가 필요하고 결과를 얻는데까지 많은 시간과 비용이 소요되는 단점이 있습니다. 전산유체역학은 이러한 문제점들을 보완할 수 있는 휼륭한 대안으로 인정받고 있습니다. 자연계에서 공기나 물 등의 유체가 우리의 관심 대상인 비행기, 자동차 등의 물체 주위를 흘러갈 때 생기는 물리 현상들은 보존의 법칙과 열역할 법칙에서 얻어지는 편미분 방정식들로 나타낼 수 있습니다. 이러한 자연계의 법칙을 나타내는 복잡한 방정식을 컴퓨터로 해석하여 데이터를 얻는 수치적인 실험 혹은 시물레이션을 전산유체역할 이라고 부릅니다.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.19 no.1
• /
• pp.25-31
• /
• 2011

The purpose of the study is to enhance the vehicle handling stability of the PACE formula vehicle. Required data for the dynamic analysis of the vehicle are as follows: Mass, moment of inertia, and tire's dynamic properties. Mass and moment of inertia data were calculated using Siemens NX 5.0 which results were verified with VIMF measurements of GMDAT. Dynamic data for the tire were supplied by Kumho Tire. Aerodynamic forces play an important role in the formula vehicle which forces were calculated by using Fluent. Full vehicle dynamic analysis using Carsim software has been carried out to find out the improvement of the vehicle stability by changing the shapes of the rear wing.