1.1 Problem Summary and Introduction
User of automotive vehicles are increasing broadly now a days. The main problem for middle
class family is facing that they need speedy car with higher vehicle performance(on basis of
average). Also some models have high speed with higher fuel consumption, so we are going to
design a vehicle body which increases performance of vehicle and lower the fuel consumption
by reducing aerodynamic forces and also maintains the aerodynamic moments for driving
stability and better traction.
For implement this project we are taking a simple sedan car model for analysis. We modified
this simple sedan car model with some aerodynamic aids like, rear spoiler, frontal air passage
and side cover.
This modification of simple sedan car is done in the CAD software like Solid works also its
analysis was done in the software like Solid-works.
Let us take a detail about aerodynamic forces and moments on vehicle body,
? The term aerodynamics is derived from geek word aeros and dynamics. Where aeros
means something that relates with air and dynamics means flow. So that aerodynamic
means study of air flow about an object.
? When a vehicle is moving on road, the air flow is dependent on the vehicle speed and
the ambient wind.
? The atmospheric wind has non uniform velocity profile and fluctuating in both
magnitude and direction
? The study of aerodynamic aspects is essential for an automobile to reduce the resistance
against the movement of vehicle and to save nearly 30% to 35% fuel cost.
Importance of aerodynamics:
? To reduce the force and moments produced on the body against the forward movement
? To save the fuel cost by better stream lining of the body
? To give good appearance by shaping the body
? To increase stability and safety of vehicle by moving
? To provide better flow pattern of exhaust and wind
? To provide better ventilation of internal body structures
Drag is the largest and most important aerodynamic force encountered by the vehicles at
normal highway speeds. The overall drag on vehicles drives from contribution of many sources
.Approximately 65% of drag arises from the body (Fore body ,after body and under
body).Major contributor is the after body because of the drag produced by the separation of
the zones at the rear. for this, in this area that the maximum potential for the drag reduction is
possible. As the angle increases the drag increases because of flow separation
As a result of the air stream interacting with the vehicle, forces and moments are imposed.
These may be defined systematically as the three forces and three moments given below.
TYPES OF AERODYNAMIC DRAG
1. Profile Drag It depends on longitudinal section of vehicle body ,for low drag co.eff a careful
choice of body profile is essential .
2. Induced drag or lift drag This is caused by vortices formed at the side of the vehicle .These
vortices are in turn caused by the aerodynamic lift of the vehicle.
3. Friction drag This is caused by friction force between the boundary layer and body surfaces
.thus well polished surface is not only attractive also makes the vehicle more economical .
4. Interference drag It includes projecting door handles ,mirrors ,Axles ,transmissions which
project out the normal surface of body.
5. Cooling and ventilation drag Proper designing of the duct of radiator in the vehicle ,type of
ventilation and exhaust system the drag co –eff can be reduced .
Direction Force Moment
Longitudinal Drag Rolling Moment
Lateral Side-force Pitching Moment
Vertical Lift Yawing Moment
Also providing some drag component names which is as given below,
? Skin friction
? Wheels and wheel wells
? Drip rails
? Window recesses
1.2 Aim and Objective of product
Our goal is to develop new design of sedan car and by this reducing the aerodynamic forces
like drag force, lift force, side force also moments created by this forces like rolling moment,
pitching moment, yawing moment respectively.
Also we are keeping in view that consumption of fuel is lesser by the designed vehicle.
1.3 Problem specification
In our project the aerodynamic forces like drag, lift and side are reduces by modifying the
simple sedan car design.
1.4 Brief literature review and Prior Art Search(PAS)
We performed a thorough web search and went through various websites and forums and noted
the various problems faced by users and their needs and requirements for our problem domain.
We also got feedback from few users. Therefore we also designed our application keeping
ourselves as the user in mind too.
In our industry search, we observed and noted that the huge implementation in aerodynamics
of vehicle body in the world. Every year we are getting a new designs of cars, this is all based
on the aerodynamic performance of vehicle body.
We also performed patent search and analysis. We went through large numbers of patents and
came up with five patents that were most related to our problem area. We shall attach the PSAR
reports at the end for reference.
We studied patents regarding reducing drag force of sedan cars. In sedan car body design
implementation like vortex generator and new bonnet design based on reducing drag force.
1.5 Plan of our Work
Project planning process was divide into two phases. The first phase included requirement
gathering and design and analysis. In next phase, modification of sedan car would being. This
would include implement of rear spoiler, frontal air passage and side cover design with their
In our 7th semester, we completed the requirements gathering and analysis for the project. We
have also finished designing and preparation of related documents. Other activities performed
included study of relevant patents for PSAR and development of various canvases such as the
AEIOU Canvas, Empathy Summary canvas, Ideation Canvas and product development Canvas
which have been useful in the understanding of the goals of the project. We are modified simple
sedan car with adding aerodynamic aids like rear spoiler, air passage, side cover etc.
In the 8th semester duration has been a learning phase for new concepts and technologies that
were implemented in the project.
1.6 CAD Tools Used :
The following are the tools which are used in our project:
This is a CAD software using for designing a car and its modification. Also this software is use
for solid modelling.
Solid-works software is divided in two parts solid modelling and surface modelling. Our car
is designed in surface modelling.
Solid-works is also used for thermal analysis or another analysis but its results are not very
useful and this analysis task is also tougher than other soft-wares.
Solid-works is also a simulation software which is mostly used for CFD analysis. Our projects
all CFD analysis was done in the Solid-Work. It is very easy for analysis purposes.
All aerodynamic forces and moments calculation is done in this Solid-work software.
CHAPTER : 2
1 External Aerodynamic Analysis of TATA Nano using Numerical Tool
Fuel efficiency is the prime focus of the present work. Simulations are carried over
external aerodynamic body to determine the drag and its coefficient by means of virtual
environment with the help of commercial tool. The use of computer software makes it possible
to be in time and cost savings. Numerical methods are employed on three-dimensional vehicle
structure to resolved body forces. The present work is carried using the ANSYS-CFX and the
equations governing fluid flow combined with standard model and solved by using the
appropriate boundary conditions. The study results of the aerodynamic analysis of the air flow,
pressure distribution and drag force on the vehicle. Few design modifications are made in the
form of attachable accessories which have been resulted in reduction of the drag coefficient.
These modifications have shown a drag reduction of 14.28% at a speed of 60 km/h with the
drag coefficient reduced to 0.336 from 0.392, thereby reducing the fuel consumption allotted
to external body by an amount of approximately 14.28%, which means, there is a saving of
2.14L of petrol for every full tank refill.
2 Aerodynamic Design of F1 and Normal Cars and Their Effect on Performance
Aerodynamics is a branch of dynamics concerned with studying the motion of air,
particularly when it interacts with the solid object. Aerodynamic is a subfield of fluid dynamics
and gas dynamics, with much theory shared between them. In this paper we are presenting the
different forces acting on a car (drag force, lift force).The measurement of forces
(computational fluid dynamics CFD and wind tunnel testing WTT). On the basis of forces and
measurement the comparison has been done over Hindustan ambassador, Lamborghini
Aventador LP 700-4 and the F1 car. The design of FORMULA1 is explained in this paper.
After detailed observation and tests performed we obtained that F1 car has most aerodynamic
of all the vehicles. The design is made in such a way that it cuts through the air with ease and
channelize the air flowing over it to the rear wings. This results in a highly reduced drag and
lift force acting on the car body. It in turn, generates more amount of down force making the
car stable at high speeds. It is the pinnacle of racing technology. On the other hand, the
Lamborghini Aventedor LP 700-4, is a full on super car. It was designed to give speed and
performancein a coupe car. thus the body had to be designed such that there is minimum air
resistance at high speed and proper cornering stability as well as drivability.
3 Aerodynamic Performance Assessment of Sedan Car by Experimental Method
The paper will describe comparative assessment of aerodynamic performance of two
different popular hatchback and sedan car model by two distinct experimental strategies of
aerodynamic predictions by conventional wind tunnel approach and its subsequent validation
with advanced computational procedures, carried out on two popular model of sedan and
hatchback car model. the experimental investigations will be performed on an open circuit
suction type wind tunnel having a 30 cm x 30 cm x 100 cm test section, on a geometrically
similar, reduced scale (1:20) aluminium car models, while the three dimensional
computational analysis was carried out using with the help of software tools like ANSYS-CFX
to simulate the flow of air around the automobiles and results like drag force, lift force, pressure
and velocity distribution, wake region, turbulence kinetic energy etc will investigated for
4 Computational Aerodynamics Research And Vehicle Engineering Development
Many Persons, both from industry and also private individuals have performed research
in regards to this new issue. Many have performed research on aerodynamics on certain
portions of the vehicle and also on effects of shape of the body and other technologies used
such as Computational Fluid Dynamics and Wind tunnel Testing. The effects of these studies
is seen in the industry today. Not so long ago, the vehicles were having shapes lose to boxes
and today beautiful curves dominate the vehicles bodies. These curves not only help in the
beauty of the vehicle but also help the vehicle in terms of aerodynamics and fuel efficiency. In
this paper we would like to highlight some important topics related with aerodynamics and
how they affect the drag of the vehicles. We shall also discuss on methods used in the industry
today to calculate the aerodynamic efficiency of the vehicles and their effects.
CHAPTER : 3
DESIGN, ANALYSIS METHODOLOGY
AND IMPLEMENTATION STRATEGY
3.1 Requirements Gathering
In this part, we discuss the different requirements and analyse them to enable us to design
and modify the sedan car.
Share a new design of a simple sedan car model with help of tools from modelling software
like Solid-works. Our purpose is to improve the aerodynamic performance of sedan car by
using different aerodynamic aids. The objective of the project is to improve the vehicle
performance with a lower fuel consumption by sedan car with respect to normal way.
Good looking design of car body with higher performance attracts the customers and it is
also a chance for us to give a new sedan car model to automobile industry
Automotive aerodynamics is the study of the aerodynamic of road vehicles. Its main goals
are reducing drag and wind noise, minimizing noise emission, and preventing
undesired lift forces and other causes of aerodynamic instability at high speeds. Air is also
considered a fluid in this case. For some classes of racing vehicles, it may also be important
to produce downforce to improve traction and thus cornering abilities.
An aerodynamic automobile will integrate the wheel arcs and lights into the overall shape
to reduce drag. It will be streamlined; for example, it does not have sharp edges crossing
the wind stream above the wind shield and will feature a sort of tail called
a fastback or kammback or liftback. Note that the Aptera 2e, the loremo, and
the Volkswagon 1-liter car try to reduce the area of their back. It will have a flat and smooth
floor to support the Venturi effect and produce desirable downwards aerodynamic forces.
The air that rams into the engine bay, is used for cooling, combution, and for passengers,
then reaccelerated by a nozzle and then ejected under the floor. For mid and rear engines
air is decelerated and pressurized in a diffuser, loses some pressure as it passes the engine
bay, and fills the slipstream. These cars need a seal between the low pressure region around
the wheels and the high pressure around the gearbox. They all have a closed engine bay
floor. The suspension is either streamlined (Aptera) or retracted.Door handles, the antenna,
and roof rails can have a streamlined shape. The side mirror can only have a round fairing
as a nose. Air flow through the wheel-bays is said to increase drag (German source) though
race cars need it for brake cooling and many cars emit the air from the radiator into the
3.1.3 System Requirement
This describes the general factors that affect the product and its requirements. Instead, it
provides background for specific user requirements, which are defined below, and makes
them easier to understand.
? Reduction of drag force and achieve maximum speed and acceleration for the same
? Reduction of drag force improves fuel economy.
? Good aerodynamic design gives better appearance and style
? Good stability and safety can be provided.
? This helps to understand the dirt flow, exhaust gas flow patterns.
? Good aerodynamic design provides proper ventilation.
3.2.1 Business Model Canvas
Fig. 3.1 : Business Model Canvas
3.3 VEHICLE DESIGN AND ANALYSIS
All the three design and its analysis are as given follow:
In our work we have design a sedan car and done a CFD analysis. The main changes in
our design is removing of side mirror because Side mirrors both increase the frontal
area of the vehicle and increase the coefficient of drag meanwhile they swell from the
side of the vehicle. In demand to decrease the influence that side mirrors have on the
drag of the vehicle the side mirrors can be replaced with smaller mirrors or mirrors with
a different shape. We were providing frontal air passage so that the air can directly
flow over the bonnet to the roof of the car and rear spoiler.
Fig 3.2 : Turbulence plot on plane
The detail calculation of work and design of car is given here. The aerodynamic is
calculated at 92 kmph flow of air over the sedan. Fig 6 show the turbulence and fig 7
showing the velocity, turbulence viscosity and temperature.
Fig 3.3. Velocity, Turbulence, Temperature
Fig 3.4. Velocity & Turbulence
Fig 3.5. Pressure & turbulence
Fig 3.6. Streamline on plane
3.3.1 AMBIENT CONDITIONS
Table 1 is the input data for the analysis. In this the thermodynamic parameters such as
static pressure and temperature is taken for the atmospheric condition. The velocity of
wind is selected as 80 kmph which describe the velocity of car.
Table 3.1. Basic details for calculation
Thermodynamic parameters Static Pressure: 101325.00 Pa Temperature: 20.05 °C Velocity parameters Velocity vector Velocity in X direction: 80.000 km/h Turbulence parameters Turbulence intensity and length Intensity: 0.10 % Length: 0.001 m Material Air (Fluid)
3.3.2 GOALS RESULT
Table 3.2. Calculated Result
Goal Name Unit Value Progress % Use In Convergence Delta GG Av Static Pressure 1 Pa 101326.9042 43.8 Yes 0.2112808 GG Av Total Pressure 1 Pa 101595.3751 21.1 Yes 3.197501059 GG Av Dynamic Pressure 1 Pa 268.2031829 20.3 Yes 2.96401303 GG Av Temperature (Fluid) 1 °C 20.07525468 19 Yes 0.0028876 GG Av Turbulent Viscosity 1 Pa*s 0.000343245 7.1 Yes 7.76152E-05 GG Av Turbulence Length 1 m 0.000979031 11.3 Yes 6.33481E-05 GG Av Turbulence Intensity 1 % 2.49984097 34.9 Yes 0.128024628 GG Av Turbulent Energy 1 J/kg 0.331257308 9.3 Yes 0.049842065 GG Av Turbulent Dissipation 1 W/kg 44.83886633 10.3 Yes 5.10868407 GG Normal Force 1 N 1.26927198 100 Yes 0.017157497 GG Normal Force (X) 1 N 1.235170877 100 Yes 0.013002128 GG Normal Force (Y) 1 N 0.292239339 49.3 Yes 0.124037735 GG Normal Force (Z) 1 N 0.000657989 100 Yes 0.000461064
GG Force 1 N 1.343900093 100 Yes 0.017304231
GG Force (X) 1 N 1.31058437 100 Yes 0.012607146
Table 3. Min/Max Table
Goal Name Unit Value Averaged Value Minimum Value Maximum Value GG Av Static Pressure 1 Pa 101326.9042 101326.9302 101326.8127 101327.024 GG Av Total Pressure 1 Pa 101595.3751 101595.8834 101593.0239 101597.1395 GG Av Dynamic Pressure 1 Pa 268.2031829 268.6847864 265.9415446 269.8606218 GG Av Temperature (Fluid) 1 °C 20.07525468 20.07477041 20.07371449 20.07719307 GG Av Turbulent Viscosity 1 Pa*s 0.000343245 0.000373072 0.000333089 0.000410705 GG Av Turbulence Length 1 m 0.000979031 0.001006515 0.00097327 0.00103972 GG Av Turbulence Intensity 1 % 2.49984097 2.346730951 2.25490543 2.49984097 GG Av Turbulent Energy 1 J/kg 0.331257308 0.346241783 0.325415879 0.375257944 GG Av Turbulent Dissipation 1 W/kg 44.83886633 44.96959236 42.77419764 49.31760416
GG Normal Force 1 N 1.26927198 1.280972923 1.266137985 1.293143394 GG Normal Force (X) 1 N 1.235170877 1.228803896 1.222168748 1.235170877 GG Normal Force (Y) 1 N 0.292239339 0.359797036 0.288117648 0.412155383
GG Normal Force (Z) 1 N 0.000657989 0.001575803 -0.000471185 0.004071063
GG Force 1 N 1.343900093 1.355109002 1.340777151 1.367243312
GG Force (X) 1 N 1.31058437 1.304477348 1.297977224 1.31058437
GG Force (Y) 1 N 0.297379825 0.364931579 0.293247269 0.417384629
GG Force (Z) 1 N 0.001143903 0.00194418 -6.69558E-06 0.004327114
GG Friction Force 1 N 0.07559005 0.075848442 0.075226039 0.076763372 GG Friction Force (X) 1 N 0.075413493 0.075673451 0.075054934 0.076586675 GG Friction Force (Y) 1 N 0.005140486 0.005134543 0.004889852 0.005295094 GG Friction Force (Z) 1 N 0.000485914 0.000368377 4.47006E-05 0.000493122
GG Torque (X) 1 N*m -0.000178922 0.000186576 -0.000273536 0.000520257
GG Torque (Y) 1 N*m 0.001160565 0.001165379 0.000940125 0.001503289
GG Torque (Z) 1 N*m -0.037943336 -0.035777674 -0.040777037 -0.032288588
GG Force (Y) 1 N 0.297379825 48.7 Yes 0.12413736
GG Force (Z) 1 N 0.001143903 100 Yes 0.000460073 GG Friction Force 1 N 0.07559005 100 Yes 0.001282829 GG Friction Force (X) 1 N 0.075413493 100 Yes 0.001300872 GG Friction Force (Y) 1 N 0.005140486 100 Yes 0.000247011 GG Friction Force (Z) 1 N 0.000485914 67.1 Yes 3.1407E-05 GG Torque (X) 1 N*m -0.000178922 31.8 Yes 0.00043307 GG Torque (Y) 1 N*m 0.001160565 100 Yes 9.41587E-05 GG Torque (Z) 1 N*m -0.037943336 65.6 Yes 0.008488448
3.3.3 Graphs Details
From Graph 1 describe the total pressure of static, dynamic and gravitational pressure
(p & q). It is the measure of the overall energy of the airflow & is equal to static plus
velocity pressure as shown in Fig 9.
Graph 2 describe the temperature changes i.e. atmospheric air temperature changes
when the air velocity is collide with the car body.
Graph 3 & 4 describe the excessive kinetic energy in parts of fluid flow, which
overcomes the damping effect of the fluid?s viscosity.
Graph 5 & 6 Describe the forces acting on the car body when wind was flowing.
Graph 3.1. Total Pressure
Graph 3.2. Av. Temperature
Total Pressure Pa
GG Av Total
Graph 3.3. Av. Turbulence Viscosity
Graph 3.4. Av. Turbulence length
Turbulent Viscosity Pa*s
GG Av Turbulent
Turbulence Length m
GG Av Turbulence
Graph 3.5. Force
Graph 6. Frictional force
Normal Force N
GG Normal Force 1
Friction Force N
GG Friction Force 1
CHAPTER 4 :
4.1 : 3D PRINTED CAR
Fig. 4.1 : 3D printed Car
Fig. 4.2 : 3D printed car
Fig. 4.3 : 3D printed car
Fig. 4.4 : 3D printed car
CHAPTER 5 :
By changing the design of car we have find that there is less aerodynamic drag, low
wind noise and we can improve 2.5 % fuel efficiency of the car.
From the table 2 & 3 we have calculated drag force „cd=0.29? and also reduces the
drag force which is created by the side mirror and also the wind noise.
The frontal pressure is 102094.50 Pa, Mach number is 0.8 and also the turbulence length
in meter is 0.005.
By improving the drag forces we can improve the vehicle mileage, better stability when
car is running, improved road holding.