The research group 9.
The topic is drag reduction of automotive van 
by vortex generator
and advisor of our
research is professor Prof.AM. Ardjit Iumrahong.
Co advisor AVM Kasem Harnchana.
And the sugesstions and assistant form
Wg. Cdr. Associate Prof. Wanchai Jiajan (PhD).
And the members of our research are ...
Hello my name is APAKORN     BOONKOMRAT
My student  ID is 60130001
My name is KAMOLCHANOK   KERDROD
my student number is 60130006
,and my name is Mongkhon Korsai
student ID 60130009
The purpose of this presentation is to let everyone know about our research the drag reduction
of automotive van by vortex generator.
Start with some video and then
presentation here we go.
[heart beat]
[laughs]
As you see here this is introduction.
The average temperature of the earth is rising twice the rate it was 50 years ago.
The way to explain the pattern is to include the effect of greenhouse gases emitted by humans see that
transportation is the major cause of global warming.
Burning fossil fuels such as gasoline and diesel discharge carbon dioxide
, which is a greenhouse gas into the atmosphere.
Therefore this project is study and
develop the aerodynamic of the
automotive van by reducing drag
for lower fuel consumption
and also help to reduce accident by
installing a vortex generator
to reduce aerodynamic drag.
Which aside from helping to save fuel,
vortex generator also helps to reduce accidents.
Accidents causing by lift like a plane wing
which affects the pressure of the tire
on the road by causing the friction on
the road to decrease
therefore controlling the car is more difficult.
As we know that the objective of the research is to reduce the drag of the car
by vortex generator in order to help
reduce global warming
let's see how vortex generator work
The vortex generator act like small wing tip
that creates a little wingtip vortex
spiral between the free steam and boundary layer these
these allow high kinetic energy from
free steam airflow mixed with
the low kinetic energy at the boundary layer
help the airflow in the boundary layer
resist the adverse
pressure gradien longer
,which pressure gradient is the force
that results when the different pressure
which cause the drag.
If the vortex generator can resist the adverse pressure gradient that's mean
the vortex generator can reduce the drag.
And next I'm talking about the important
related theories in our research.
The first one is Law of similarity.
Due to a scale effect
or the incomplete similarity
we cannot achieve the full scale of the
model and the prototype
so the law of similarity must be
considered.
The law similarity split into three
level the first level is the
Geometric Similarity is to maintain all corresponding ratio of the length
That's means the model
and the prototype are the same shape.
The second level of law of similarity is
the kinematic similarity
is to maintain our ratio of length
and times which refer to the velocity
and the third level is the dynamic
similarity
is to maintain of the ratio of the
forces.
The law similarity was applied in the
scaling process
with the other condition which is the
condition of speed and size.
The speeds must be highest as possible
to obtain the Reynolds number
that close or equal to the reality.
And the size the cross-section area of the model compared with the cross-section area of the
test section must be considered to avoid
the effect of the solid blockage
and wall interference which these effect
can cause the value from experiment being improper.
And next theory is the aerodynamics.
Aerodynamic is the study of force and
the resulting motion of the object to the air.
There are lift weight thrust and drag
,which drag force is the force that resists
the movement of the object.
that caused by the friction of the air 
this can be the main factor of the fuel consumption
in aerodynamics we trend to use the theory of drag to improve the aerodynamic of the vehicles.
which drag force can be calculated by
this equation D equal to one-half times cd times a times low time v square
which cd is drag coefficient low cd value
can help saving fuel, especially at
high velocity
Subsonic Research Wind Tunnel
To operate safety , we need to operate
the subsonic wind tunnel under the
limitation of the equipment
and need the engineer approval to
testing on the subsonic research wind tunnel.
Test section have 2 times 1.5 times 5.805 m
and 25 mm clear acrylic wall 
27 mm marine plywood floor and roof
and turntable diameter of 1.6 m
For the subsonic wind tunnel given
details at the board range
Normal force at 1335 N
Side Force at 667 N
Axial Force at 356 N
Pitching Moment at 56 N.m
Yawing Moment at 28 N.m
and Rolling Moment : 28 N.m
And next related research.
The aerodynamic reduction in passenger vehicles using vortex generator
with varying yaw angle.
This journal was
published by
the department of automobile engineering in Anna university of technology.
The research tests a vortex generator with varying angles.
Found that the angle between 10 to 17 degree
 of vortex generator
can reduce the drag
but if the angle is more than 17 degree
the drag was increased instead
therefore from this journal the researcher can decide the angle of vortex generator.
and next the research on
Aerodynamics drag reduction by vortex generators
this journal was published by studio
package engineering department
research and development office of mitsubishi motors .
this research tracker was to save the
energy due to global warming by study
about the
drag reduction by vortex generator of ground vehicles
research  study about the
bump shape vortex generator
and the delta wing shape vortex generator.
Which the most efficient vortex generator type is the delta wing shape vortex generator
therefore we designed
to use the delta wing shape vortex generator
to test in our research.
Methodology
First design and create the model after
obtaining a dimension of a model
the engineering drawing was done to
specify the size and shape of a part
and externally for accurate dimension
manufacturing process.
Next creat a model of automotive van that's match with protitype of GMC Vandura
by 3D printing PLA filament.
Sanding and Priming process, the model was sanded by sand paper
to remove
material for surface and a layer of
material to make them smoother
and then the print primer was applying
on the van model for a preparatory
clothing put on the model before painting.
Priming process was on a better adhesion
of paint to the surface
increased paint durability and provided
additional protection
for the model being planted.
Painting process
the model was painted to protection of
the past surface
from the environmental factor such as
oxygen and other chemically active gas
moisture dissolved soil on other
chemical
temperature bacteria fungi
so corrosion protection was the most
important
function of  paint.
So moving on to the
vortex generator implementation due to
the height of vortex generator defined by
calculated Reynolds number of the
prototype to see the thickness of the
boundary layer on the flat plate
the vortex generator was designed in
size of 42.5
times 17 times 8.5 cm
so this is the dimensional 
and height  that we were define
the prototype of the vortex generator can be provided
so before the vortex generator were produce
it had to be confirmed that it
testable.
So this is the vortex generator with no angle.
The vortex generator with angle of 10
degrees.
The vortex generator with angle of 15 degrees.
and this is the vortex generator with angle of 20 degrees
so this is the model after we install the vortex generator with all different angles
so at the testing process the model was
set up on the string balance.
The researcher needs to obtain the
engineering approval, that the model is durable enough
to hold against the high speed wind of windtunnel, afterward the model was tested
without the vortex generator at speed of 30 35 40 and 45 meters per second respectively.
This steps were repeated for two time
to ensure the accuracy of data.
At the left-hand side you can see that
this is we proposal before we test it.
So moving on.
The vortex generator install with angle of 10, 15 and 20 degrees
and test it on the wind tunnel sequentially.
Finally, the researcher collected the data from the wind tunnel and applied on the calculation method.
The wind tunnel inform drag value which could calculate into the drag coefficient.
In addition, the graph was plot between drag coefficient and Reynolds number , which we show the
result of the drag reduction at the
each installation angle.
Schedule.
First sent finish drawing to part
manufacturer.
Second waiting for manufacturing process.
Third combine the vortex generator with automotive model.
Fourth test and verification with wind tunnel.
Next discussion and conclude
the testing result.
And last project presentation and submit
the complete hard copy.
Next the calculation part, first i would like to recall
the calculation part from previous progress presentation.
First, the Reynolds number of the prototype was calculated by this equation
where the velocity of the van is around 100 to 120 km/hr
so the Reynolds number of the prototype is 9867825.495
, which is the turbulent flow.
Then the thickness of boundary layer was
calculated by this formula
, which is the formula of turbulent boundary layer thickness.
Then the height of boundary layer of the
prototype  was 8.407 cm
so if the vortex generator need to spiral the high kinetic energy from the free steam air
to resist the adverse pressure gradient.
The height of the vortex generator must
be higher than the thickness of boundary layer.
Then the researchers decide the height of vortex generator of the prototype to be
8.5 cm, which is greater than the
height of boundary layer.
Then find all dimensions of vortex generator
by the ratio of dimension from the research of effect of vortex generator
on aerodynamics of car by CFD analysis.
Then the dimension of prototype's  vortex generator
was defined.
After that
the researchers scaled down the prototype 8 times
to avoid the effect that may be caused by solid blockage and wall interference
and these is the dimension of the model's vortex generator.
After the process of manufacturing
the experiment was run.
The data collected from experiment is the drag force
, which collect 14 count of each velocity
and find the average to obtain the precise value.
Then find the average by this equation get the average
drag force of the model without vortex generator
at 30 m/s equal to 3.94329 lbf
Then repeat thesolution to find the average drag force
of all model at each velocity.
But !!
The drag force collected from experiment was in the British unit
then we changed to International system
unit in order to make it easier to calculate.
By multiplying 4.4 4822 to convert from lbf to N
Then find the drag coefficient from theory of aerodynamics.
The drag coefficient equal to 2 times drag force
divided by density of air times
cross section area times velocity square.
And this is the example of calculate drag coefficient
of model without vortex generater
at 30 m/s
The average drag force equal to 3.94329 lbf
Then multiply 4.44822 to convert into N
get the average drag force equal to 17.54 N
then substitute the value into the equation
which the drag coefficient equal to 2 times drag force
, which is 17.54 N
divided by density of air in the test section
, which is 1.15 kg/m^3
times cross-section area of the model 
, which is 0.06964 m^2
times velocity square, which is (30 m/s)^2
then get the drag coefficient of the model without vortex generated at 30m/s
equal to 0.4828
and at 35 m/s the average drag force was equal to 5.20829 lbf
then substitute the value into equation
get the drag coefficient of the model
without vortex generator at 35 m/s
euqal to 0.47233
Then the researcher repeat the solution to find
the drag coefficient of each model at each velocity.
Get the drag coefficient as these table.
After that the drag coefficient was plot 
against with the Reynolds numbe
to compare the drag coefficient between
with and without vortex generator.
The lower line refers to the lower drag coefficient.
In order to make it easier to see which one is the most efficient
the different percentage between before and after install the vortex generator was calculated.
and this is our calculation part of our research
Next the discussion.
So from now we are going to talk about the discussion.
First, no angle installation the vortex generator is applied on the rear end of the van model
with inclination no angle.
The coefficient of drag was 0.4828
at a velocity of 30 m/s
0.47 and velocity of 35 m/s
0.45 at velocity of 40 m/s
and 0.38 at velocity of 45 m/s
Next the inclination angle 10 degrees
The coefficient of drag was 0.428 velocity of 30 m/s
0.427 at velocity of 35 m/s
0.416 at velocity of 40 m/s
and 0.357 at velocity of 45 m/s
The percentage reduction in drag
coefficient is comparison with uninstall vortex generator
, which is 11.3%, 9.5% ,7.6% and 5.994%
Hence, drag force and coefficient of drag on the passenger car were reduce
as proportional to drag coefficient respectively.
So we are moving on to the third one.
The inclination angle 15 degrees.
The percentage reduction in drag coefficient is comparison with the uninstall vortex generator
, which is 7.83% , 5.66%, 3.13% and -0.71%
Hence, drag force and coefficient of drag on the passenger car were reduce
as proportional to drag coefficient respectively.
So we're moving on to the next one.
The inclination angle of 20 degrees.
The coefficient of drag and the percentage
reduction in drag coefficient
in comparison with the uninstallable vortex generator.
were 10.89%,8.42%, 6.05% and 3.23 %
The drag force and the
coefficient of drag on the passenger car
were reduced and proportional to the
drag coefficient respectively.
Due to a result from the calculation
part clearly showed that
the drag coefficient was decreased
But!!!!
when at the higher angle of vortex generator 
and higher velocity
drag trend not to decrease but increase instead.
Because vortex generator work by generating vortex
to pull a high kinetic energy from free steam air 
to the boundary layer
,which help the flow attach the surface further
so less  wake less drag.
It's true that a higher angle of vortex generator can create more vortex but it also creates a drag.
However, it must have the most efficient angel.
When compare the drag coefficient at the same speed
or the same Reynolds number.
Can see that vortex generator has essential role in
improving aerodynamic, drag reactions 
and decreasing fuel consumptions.
For the conclusion the vortex generator perform as we expect
, which demonstrates high effectiveness
and excellent potential for reducing the drag coefficients.
In this experiment the most efficient is the model with 10 degrees vortex generator
, which coefficient of the drag was reduced by 11.3 %
, which compared to the model 
without the vortex generator.
It also has a tendency to have
coefficient of drag less than the other models
according to the incremental Reynolds number.
As said by the researcher we want to reduce the drag of the vehicle to reduce the global warming.
So according to the result of the experiment the vortex generator has ability to reduce the drag coefficient
by generating vertices
, which this voltage mix the high energy free
steam air to the lower energy boundary layer
, which is allowing the airflow to resist 
the adverse pressure gradient longer
and delay the boundary layer separation 
causing drag reductions.
So for this advantage the vortex generator are suggested to be used in the commercial application
for the ground vehicles and even in the aviation industrial for the drag reductions
And next the conclusions of procedure and schedule.
The blue color represented the procedure in first semester.
The yellow represented the procedure in second semester.
Green represented the procedure 
that follow the plan.
Red represented the procedure that delayed from the plan
And orange represented the procedure that faster than the plan
In the preparation part.
The define topic, study the theory,
find the equipment and materials sources
and the cost estimation are flowed the schedule.
Next the model manufacturing process.
The selection of equipment and materials
and manufacturing process are going as planned
, but the the drawing process was delayed.
Because at first we select the truck tiller to be our model
but the truck model cannot withstands high speed wind in the wind tunnel
so we has to change the model, then this cause the delay of drawing process of the model.
And next the vortex  generator implementation.
All process of vortex generator manufacturing process are faster than we thought
, cause the vortex generator implementation ahead the schedule.
And next the verification and testing process .
Even the vortex generator done faster than we planed
, but we already reserved the testing day for the wind tunnel
so the testing and verification are going as we planed.
And calculation, discussion and conclusions of the research are followed the plan.
This is all our presentation.
Thank for watching.
