DRAG FORCE ANALYSIS OF CAR AUTHORS ABHISHEK KUMAR RAVISHEK KUMAR SESSION 2005-2006 DEPARTMENT OF MECHANICAL ENGINEERING G. H. RAISONI COLLEGE OF ENGINEERING, NAGPUR.
CONTENTS • Introduction • Motivation • Regimes of External Flow • Profile Drag • Minimizing Drag on a LMV • Expression For Drag Force • Stream-lined and Bluff Body • Components of Drag • Thrust Vs Speed of Car • Project • Limitations • Conclusion • References
INTRODUCTION • Decreasing the fuel consumption of road vehicles. • Drag is one of the most important issues when it comes to Aerodynamics design of road vehicles
MOTIVATION • Designing a vehicle with a minimized drag resistance provides economy and performance advantages. • The main motivation for reducing drag resistance is: • Fuel consumption reduction • Performance increasing
REGIMES OF EXTERNAL FLOW External Flow of Fluid on Vertical Plate
PROFILE DRAG • Pressure drag • Friction drag Profile drag = Pressure drag + Friction drag
Expression For Drag Force • The Drag force value for a moving vehicle is given by the following expression. DF =1/2 A ρ CD V2 where , CD is the drag coefficient A is the projected frontal area of the vehicle ρ is the density of air V is the speed of the vehicle relatively to the air
MINIMIZING DRAG ON A LMV(CAR) SHAPE OF VEHICLE’S BODY
PROJECT DIMENSIONS : OVERALL LENGH 3335 mm OVERALL WIDTH 1440 mm 2D SCETCH OF MARUTI 800
LIMITATIONS • Space Constraint • Styling may be the most flagrant example: Consumers/buyers always seek for a certain ‘look'. This concept is today very different from the aerodynamically ‘ideal’ car. • Drag and Lift Relation
CONCLUSION • Smooth vehicle shape, rounded corners. • Tapered rear end. • Minimized body seams. • Substitution of rear view mirrors with Cameras. • Smooth underbody.
REFERANCES 1. Paper: Optimization of Body Shape through Computation of Aerodynamic Forces on Low Mass Vehicle (LMV) By Inchul Kim and Xin Geng 2. Paper: Reducing Drag Forces in Future Vehicles by Alexander Diehl, Jose Nuno Lopes, Rui Miranda, Christoffer Mursu Simu and John Viji. 3. Book: Fluid Mechanics By John f Douglas, Janusz M Gasiorek and John A Swaffield. 4. Websites: www.engin.umd.umich.edu/ceep/tech_day www.marutiudyog.com www.princeton.edu/~asmits/blunt.html