IMPACT OF AERODYNAMICS ON AUTOMOBILES
INTRODUCTION Aerodynamic forces are caused by the relative motion of automobiles with air and they cause: Drag (resistance to forward motion) Lift / down force (come into play during cornering and acceleration) Lateral forces (comes into play during cornering) Moments in roll, pitch and yaw As a result these factors have to be taken into consideration during automobile design. THEORY BEHIND AERODYNAMIC FORCES The sources of aerodynamic forces are Viscous forces Drag (form drag) The major among both of these is the form drag caused by pressure differences between the front part and back part of the vehicle.

EFFECT OF VEHICLE DESIGN ON DRAG & DOWNFORCE
In this project an effort is made to study the effects of vehicle design on drag and down-force. A CFD analysis of air-flow around an automobile is carried out using the following vehicle designs. Jeep Sedan Fast sedan Sedan with a spoiler The first three are used to study drag and the last is used to study down-force. The following figures Fig. 1, 2, 3, 4 show the 2-D models of the above mentioned vehicle designs:

Fig.1 A 2-D model of a ‘Jeep’.

Fig.2 A 2-D model of a ‘Sedan’.

Fig.3 A 2-D model of a ‘Fast Sedan’.

Fig.4 A 2-D model of a sedan with a rear wing (spoiler).

CFD ANALYSIS OF AIR FLOW OVER VEHICLES
The pressure field across the vehicles is solved in the commercial software ANSYS. The following section describes the procedure used to solve the pressure and velocity fields.

METHODOLOGY
Creation of 2-D models of different vehicle design is carried out in Pro-Engineer and imported to ANSYS Solution domain (domain of interest) is created using enclosures of required dimensions and air is chosen as its medium. Meshing of the solution domain is done using automatic mesh generator. Initially a coarse meshing done and after realistic solutions are obtained the mesh is made...

...COURSE ON VEHICLEAERODYNAMICS
Prof. Tamás Lajos University of Rome “La Sapienza” 1999 1. Introduction Subject of the course: basics of vehicleaerodynamics ⇒ ground vehicleaerodynamics ⇒ examples in car, bus, truck aerodynamics. Main objectives of vehicleaerodynamics: - reduction of drag and fuel consumption, - improvement of operational characteristics (stability, safety, handling characteristics) - improvement of comfort characteristics (noise generation, mud deposition etc.) 3 flow fields: - flow past vehicle bodies, - flow in passenger compartment (ventilating, heating), - flow in and around components (cooler, brakes etc.) 2. History 4 periods: - 1900 -1920 Adaptation of the form of different vehicles (e.g. boats and airships) and devices like bodies (e.g. torpedoes), - 1920 -1970 Utilisation of the results of aeroplane aerodynamics. Gap between aerodynamic achievements and the mass production of cars. Pál Járay, Klemperer: optimum body shape near the ground, car bodies constructed by combining wing and airship sections. Kamm: cut of long tail of Járay's cars. - 1970 - Form optimisation: starting from a given car body configuration meeting the needs of consumers, technological, styling and safety requirements etc. and changes of body shape will be carried out to improve the...

...AerodynamicsAerodynamics is a branch of fluid dynamics concerned with the study of gas flows. The solution of an aerodynamic problem normally involves calculating for various properties of the flow, such as velocity, pressure, density, and temperature, as a function of space and time. Understanding the flow pattern makes it possible to calculate or approximate the forces and moments acting on bodies in the flow. This mathematical analysis and empirical approximation form the scientific basis for heavier-than-air-flight.
Aerodynamic problems can be classified in a number of ways. The flow environment defines the first classification criterion. External aerodynamics is the study of flow around solid objects of various shapes. Evaluating the lift and drag on an airplane, the shock waves that form in front of the nose of a rocket or the flow of air over a hard drive head are examples of external aerodynamics. Internal aerodynamics is the study of flow through passages in solid objects. For instance, internal aerodynamics encompasses the study of the airflow through a jet engine or through an air conditioning pipe.
The ratio of the problem's characteristic flow speed to the speed of sound comprises a second classification of aerodynamic problems. A problem is called subsonic if all the speeds in the problem are less than the speed of sound,...

...Race Car Aerodynamics
Gregor Seljak
April 8, 2008
1
Introduction
First racing cars were primarily designed to achieve high top speeds and the
main goal was to minimize the air drag. But at high speeds, cars developed
lift forces, which aﬀected their stability. In order to improve their stability
and handling, engineers mounted inverted wings proﬁles1 generating negative
lift. First such cars were Opel’s rocket powered RAK1 and RAK2 in 1928.
However, in Formula, wings were not used for another 30 years. Racing in
this era 1930’s to 1960’s occured on tracks where the maximum speed could
be attained over signiﬁcant distance, so development aimed on reducing drag
and potencial of downforce had not been discovered until the late 1960’s. But
since then, Formula 1 has led the way in innovative methods of generating
downforce within ever more restrictive regulations.
Figure 1: Opel’s rocket powered RAK2, with large side wings
2
Airfoils
Airfoil can be deﬁnead as a shape of wing, as seen in cross-section. In order
to describe an airfoil, we must deﬁne the following terms(Figure 2)
• The mean camber line is a line drawn midway between the upper and
lower surfaces.
• The leading and trailing edge are the most forward an rearward of the
mean camber line.
1
Compared to an aircraft
1
• The chord line is a line connecing leading an trailing edge.
• The chord length is the distance from the leading to the trailing edge,...

...Mechatronics Engineering Vol:8 No:5, 2014
3D Numerical Studies on External Aerodynamics of
a Flying Car
International Science Index Vol:8, No:5, 2014 waset.org/Publication/9998307
Sasitharan Ambicapathy, J. Vignesh, P. Sivaraj, Godfrey Derek Sams, K. Sabarinath, V. R. Sanal Kumar
Abstract—The external flow simulation of a flying car at take off
phase is a daunting task owing to the fact that the prediction of the
transient unsteady flow features during its deployment phase is very
complex. In this paper 3D numerical simulations of external flow of
Ferrari F430 proposed flying car with different NACA 9618
rectangular wings have been carried. Additionally, the aerodynamics
characteristics have been generated for optimizing its geometry for
achieving the minimum take off velocity with better overall
performance in both road and air. The three-dimensional standard komega turbulence model has been used for capturing the intrinsic
flow physics during the take off phase. In the numerical study, a fully
implicit finite volume scheme of the compressible, ReynoldsAveraged, Navier-Stokes equations is employed. Through the
detailed parametric analytical studies we have conjectured that
Ferrari F430 flying car facilitated with high wings having three
different deployment histories during the take off phase is the best
choice for accomplishing its better performance for the commercial
applications.
Keywords—Aerodynamics of flying car, air...

...Advantages of Aerodynamics for Modern Performance Cars
Advantages of Aerodynamics for Modern Performance Cars
Thesis: Aerodynamics, the effects of air flow over surfaces, is an indispensable element for modern cars' efficiencies, both economics and performance related, because aerodynamics helps to decrease the dragforce, makes cars more stabilized and gives a chance of reducing fuel consumption.
I. Performance
A.Aerodynamics Basics
1. Theory
a. Air flow
b. Pressure and forces
2. Cornering
a. Drag
b. Dawnforce
3. Modeling and testing
a. CFD
b. Wind tunnels
4. Coefficient of drag
a. speed
b. efficiency
B. Aerodynamics Parts
1. Front - Naca Ducts
2. Rear
a. Side skirts
b. Side ducts
3. Back
a. Spoilers
b. Wings
c. Diffusers
II. Economy
A. Trucks
B. Family cars
Does it seem reasonable that Ferrari spent $15.5 million on aerodynamic research and development last year? What justifies this massive investment? All is about improving the performance of the car by using fluid dynamics techniques. Vast sums of money from the world's biggest and richest sponsors are spent to gain maybe just 0.001 seconds through improved aerodynamics which create the difference between winning and losing. Moreover huge effort is put in to through...

...basic factors affecting road vehicle drag and their associated affects
0718572
School of Engineering, University of Warwick
Coventry, West Midlands, U.K
Abstract: It is possible to improve the aerodynamic efficiency of road vehicles and reap many benefits. Fuel consumption being one of them, this report identifies how basic theoretical and experimental fluid mechanics can work in harmony to allow one to understand the key mechanisms that affect the aerodynamic properties of road vehicles and suggest ways in which to analyse them. From this it is possible to learn and improve upon current design practices to ensure cleaner more fuel efficient, environmentally friendly road vehicles of the future.
1. Introduction
In the 70’s with the emergence of the worldwide oil crisis nations were being urged to adopt energy conservation methods. The United Nations estimate the world’s population is set to reach 8 billion by 2025 based on current rate of growth. The demand on producing energy is placing great stress on our environment. Considering almost every household owns at least 1 car by 2025 there could be 1 billion cars alone on the road requiring fuel of some sort. Therefore it is necessary to produce road vehicles that are fuel efficient. Aerodynamic drag and fuel consumption are linked, simply the poorer the aerodynamic efficiency of...

...AERONAUTICS: A DESIGN PERSPECTIVE
CHAPTER 3: AERODYNAMICS AND AIRFOILS
“Isn’t it astonishing that all these secrets have been preserved for so many years just so that we could discover them!!”
Orville Wright
3.1 DESIGN MOTIVATION
The Physics of Aerodynamic Forces
Figure 3.1 shows a cross section view of an aircraft wing. A wing cross section like this is called an airfoil. Lines drawn above and below the airfoil indicate how the air flows around it. The shape of the airfoil and the pattern of airflow around it have profound effects on the lift and drag generated by the wing. Aircraft designers choose a particular airfoil shape for a wing in order to optimize its lift and drag characteristics to suite the requirements for a particular mission. It is essential that an aircraft designer understand how the changes that occur in air as it flows past a wing create lift and drag, and how airfoil shape influences this process.
Figure 3.1. Flowfield Around an Airfoil
The Basis for Airspeed Indication
The changes which occur in the properties of moving air as it encounters obstructions provide the basis for the airspeed indicating systems used on most aircraft. An understanding of how these systems work is essential to anyone who designs, builds, or operates aircraft.
3.2 BASIC AERODYNAMICS
The Language
A number of terms must be defined to facilitate a discussion of...