International Journal of Advanced Engineering, Management and Science (IJAEMS) [Vol-3, Issue-8, Aug- 2017] https://dx.doi.org/10.24001/ijaems.3.8.6 ISSN: 2454-1311 www.ijaems.com Page | 850 Design modification on Indian Road Vehicles to Reduce Aerodynamic Drag P.Vinayagam*, M.Rajadurai, K.Balakrishnan, G.Mohana Priya Department of Aeronautical Engineering, Mahendra Engineering College, Namakkal, Tamil Nadu, India Abstract— Reducing vehicle fuel consumption has become one of the most important issues in recent years. Aerodynamic drag contributes to 50-60% of fuel consumption in trucks on highways. Vehicle aerodynamic performance is mainly determined by drag coefficient, which directly affects engine requirements and fuel consumption. It’s well known that drag changes in a crosswind compared with a condition without a crosswind, and that the change depends on the vehicle shape. Pressure drag, a major drag for trucks as they run at lower speeds is produced by the shape of the object. Therefore, addition of some components can suffice the need. The vehicle has been designed by using Catia and then analysed with CFD. The values are compared and the resultant drag reduction is calculated. Keywords— Aerodynamics drag, CATIA, CFD, fuel consumption. I. INTRODUCTION Vehicles with an aerodynamic shape use less fuel. Air flows easily over them and less energy is needed to move them forward. At 95 Km/h 60-70% of a vehicle’s energy is used to move it through the air, compared with only 40% at 50 Km/h .installing a sloping front roof on a lorry could save you as much as 7% of your fuel costs. Even small changes to design and shape will make a difference. Take a look at the Aerodynamic checklist, walk around your vehicle and look at each feature to see what improvements you can make. This document covers the aerodynamic styling of commercial vehicles. Vehicles that travel at higher speeds and for longer distances will benefit most from aerodynamic styling, giving you greater savings. Drag is the energy lost pushing through air, and it accounts for most of the fuel used on long- distance journeys, regardless of vehicle type. Overcoming drag uses approx. 60% of fuel used at cruising speeds when loaded, 70% when empty. Sharp corners, racks and parts that stick out will add “parasitic drag”, further reducing fuel efficiency. Fuel consumption due to aerodynamic drag consumed more than half of the vehicle’s energy. Thus, the drag reduction program is one of the most interesting approaches to cater this matter. Aerodynamic drag consists of two main components: skin friction drag and pressure drag. Pressure drag accounts for more than 80% of the total drag and it is highly dependent on vehicle geometry due to boundary layer separation from rear window surface and formation of wake region behind the vehicle. The location of separation determines the size of wake region and consequently, it determines the value of aerodynamic drag. According to the aerodynamic drag of a road vehicle is responsible for a large part of the vehicle’s fuel consumption and contributes up to 50% of the total vehicle fuel consumption at highway speeds. Reducing the aerodynamic drag offers an inexpensive solution to improve fuel efficiency and thus shape optimization for low drag becomes an essential part of the overall vehicle design process. It has been found that 40% of the drag force is concentrated at the rear of the geometry. Investing in good aerodynamic styling on new trucks will repay your investment. Manufacturers go to enormous expense using wind tunnels to improve aerodynamic stability and reduce parasitic drag. The truck pictured is an example of good aerodynamic styling and air management. To understand how this styling reduces your fuel consumption look at the simplified diagram below of an articulated truck without any curved edges. Also note that there is a large gap between the tractor and the trailer. Compare this with the well styled tractor and trailer in the second picture. You’ll see that there are fewer areas of turbulence and turbulence causes drag. The second vehicle will use less fuel. Ensure that air can flow easily and smoothly over the shape of your vehicle, by minimizing things that stick out and block the air’s passage. Wherever possible chose smooth sided designs, curved edges, hidden buckles and a close gap between your tractor and your trailer. Fig.1: Flow over on a vehicle