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Proceedings of the
International Conference on Mechanical Engineering and Renewable Energy 2017
(ICMERE2017) 18 – 20 December, 2017, Chittagong, Bangladesh
ICMERE2017-PI-113
A COMPARATIVE STUDIES ON VARIOUS MODEL BIRD’S WING & STANDARD
AIRFOIL & ALSO TRACK DOWN THE MOST EFFECTIVE AIRFOIL USING CFD
SOLVER SOFTWARE.
Md. Nesar Ali [1], Shamim Anwar [2], Dr. Md. Mahbubul Alam [3]
1, 2 Graduate, Chittagong University of Engineering & Technology (CUET), Bangladesh
3 Professor, Chittagong University of Engineering & Technology (CUET), Bangladesh
nesarali455@gmail.com [1], captured.tomal@gmail.com [2], malam@cuet.ac.bd [3]
Abstract: The subsistent work describes the comparative analysis on various prototype model bird’s wing and
standard airfoil. For proceeding our experimental studies we fabricated several types model bird’s, insect’s wing like
Dove wing, Fly’s wing, Mosquito wing and other standard airfoil like NACA 64A012 mod airfoil. To seek out the
better airfoil we also fabricated various supersonic combat aircraft like Mig-29, F-7 BG, F-22 raptor, Supermarine
Spitfire Elliptical wing as well. The fundamentals of bird and insect flight are similar to those of aircraft flight. The
action of air flow that produces lift forces on the wing which is known as airfoil. These airfoil is structured such that
the air stream provides a net upward force on the airfoil. Since aerodynamic characteristics of an aircraft (wing
loading, aerodynamic efficiency) are greatly rely on wing or airfoil, it should be varied from aircraft to other aircraft.
This is why low speed aircraft has normal shaped symmetrical wing and supersonic combat aircraft has special shaped
wing because it needs greater lift with small angle of attack. Secondly, we analyze those model wing on CFD solver
software like SOLIDWORKS (flow simulation) to evaluate its flying ability such as lift force, drag force at different
angle of attack. Finally, our ultimate goal is to track down the better airfoil or wing of these model bird’s or insect’s
wing and different combat aircraft airfoil.
Key words: Model wing, Wing loading, Aerodynamic characteristics, CFD solver software, Flow simulation.
1. INTRODUCTION
Aerodynamics is the study of forces and the
resulting motion of objects through the air. Studying
the motion of air around an object allows us to measure
the forces of lift, which allows an aircraft to overcome
gravity, and drag, which is the resistance an
aircraft “feels” as it moves through the air. [1]
Aerodynamic force is exerted on a body by the air (or
some other gas) in which the body is immersed, and is
due to the relative motion between the body and the
gas. Aerodynamic force arises from two causes. They
are the normal force due to the pressure on the surface
of the body and the shear force due to the viscosity of
the gas, also known as skin friction. When
an airfoil (or a wing) is moving relative to the air it
generates an aerodynamic force, in a rearward
direction at an angle with the direction of relative
motion. This aerodynamic force is commonly resolved
into two components. Which are the drag is the force
component parallel to the direction of relative motion
and the lift is the force component perpendicular to the
direction of relative motion. The design and analysis
of the wings of aircraft is one of the principal
applications of the science of aerodynamics, which is
a branch of fluid mechanics. The properties of the
airflow around any moving object can in principle be
found by solving the Navier-Stokes equations of fluid
dynamics. [2]
In this paper comparative analysis has been done
on various model standard airfoils and prototype bird’s
wing at low- Mach number. The goal of this paper is
to seek out that, which airfoil is the most suitable and
efficient to be used in a low-speed aircraft and having
maximum lift with respect to minimum drag on the
basis of their Lift-to-Drag ratio, Lift coefficient, Drag
coefficient and Moment coefficient under the
specified boundary conditions and the value of Mach
number varies from 0.10 to 0.30.
2. METHODOLOGY
2.1 AIRFOIL MODELLING:
The geometry of all airfoil and wing like F 22
raptor, F7 BG, Mig 29, Spitfire Elliptical Wing,
NACA 64A012 mod airfoil, Dove wing, Fly wing &
Mosquito wing are generated in SOLIDWORKS.
Above mentioned those airfoil NACA 64A012 mod
Proceedings of the
International Conference on Mechanical Engineering and Renewable Energy 2017
(ICMERE2017) 18 – 20 December, 2017, Chittagong, Bangladesh
ICMERE2017-PI-113
airfoil is the only standard airfoil. Here the coordinates
of NACA 64A012 mod airfoil are taken from UIUC
official website. For achieving practical unsteady
aerodynamics knowledge we also select many bird
wing like DOVE wing, Fly wing & Mosquito wing.
Those bird wing are also modeled by using
SOLIDWORKS. We don’t use any conventional
parameter to model those wing. It’s just replica of
DOVE wing, Fly wing & Mosquito wing actual image.
We just see the actual top view of DOVE wing, Fly
wing & Mosquito wing as our model bird’s wing cross
section. For further wing analysis we also model
supersonic fighter aircraft wing like model: F 22
raptor, F 7 BG, MIG 29 & Spitfire Elliptical wing. As
we mentioned earlier that while we modelling those
wing on SOLIDWORKS we don’t use any
conventional parameter to model those wing. From the
cross sectional images of those wing are the
approximate cross section of our model wing.
2.2 MESH GENERATION:
SOLIDWORKS Flow simulation is a new class of
CFD (Computational Fluid Dynamics) analysis
software (called concurrent CFD) that is fully
embedded in the mechanical design environment, for
all general engineering application. The idea is
underpinned by the choice of meshing technology in
SOLIDWORKS Flow simulation and the impact that
impact that choosing a Cartesian based mesh has on
the way the geometry is handled. Special character of
SOLIDWORS Flow simulation that is the automatic
meshing system will create mesh in accordance with
the specified minimum gap size, minimum wall
thickness and result resolution level. Different model
wing has been built using the above data table and
coordinates using the ‘Curves using XYZ point’
function. Chord length was taken 171mm and span
taken 94 mm for the convenience of using the airfoil
in wind tunnel.
2.3 PROTOTYPE:
For practical aerodynamic analysis we also made
prototype model airfoil of F 22 raptor, F7 BG, Mig 29,
Spitfire Elliptical Wing, NACA 64A012 mod airfoil,
Dove wing, Fly wing & Mosquito wing. In this this
sense wind tunnel testing is the best way to determine
and calculate aerodynamic characteristics of airfoil.
Those wing was built for wind tunnel experiment with
the predefined chord length (171 mm) and span (94
mm) with the average height of those airfoil in
between ‘3.2 cm’. The prototype was built in the
workshop of Mechanical dept. of CUET. Beech wood
(Gamahr) was used as material to make those airfoil
model.
Fig 1: NACA 64A012 mod (model)
Fig 2: Elliptical Wing (model)
Fig 3: Dove Wing (model)
Fig 4: F7 BG wing (model)
Proceedings of the
International Conference on Mechanical Engineering and Renewable Energy 2017
(ICMERE2017) 18 – 20 December, 2017, Chittagong, Bangladesh
ICMERE2017-PI-113
Fig 5: F22 raptor Wing (model)
Fig 6: Fly’s Wing (model)
Fig 7: MIG 29 wing (model)
Fig 8: Mosquito Wing (model)
2.4 AIRFOIIL SELECTION:
The most important and valuable task is to
choice an airfoil and suitable bird wing on which the
analysis will be done. This study will extremely vary
from foil to foil. Consequence that came out from one
foil can’t be used to predict behavior of another foil.
In this project F 22 raptor, F7 BG, Mig 29, Spitfire
Elliptical Wing, NACA 64A012 mod airfoil, Dove
wing, Fly wing & Mosquito wing was selected and all
these prototype wing and model bird wing are shown
above. The standard airfoil like NACA 64A012 mod
airfoil is the first family of NACA airfoils developed
in the 1930s, was the “five-digit” series, such as
NACA 64A012 mod airfoil. This airfoil is used in L-
39 Albatross light combat subsonic training aircraft By
Bangladesh Air Force, China Air Force, Russian Air
Force and Czech Air Force as well. We also choose
bird’s wing like ‘Dove’ wing and insect’s wing like
‘Fly’s wing’ & ‘Mosquito wing’. The prime function
of the wing is to generate lift force. This will be
generated by special wing cross section called airfoil.
Wing is a three dimensional component, while the
airfoil is two dimensional section. Because of the
airfoil section, two other outputs of the airfoil, and
consequently the wing, are drag and pitching moment.
The wing may have a constant or anon-constant cross-
section across the wing. On the other hand, The
Supermarine Spitfire aircraft used elliptical wing. And
we select elliptical wing because furthermore studies
of aerodynamics equation and Prandtl’s lifting line
equation about finite wing theory we realize that the
elliptical wing has much higher aerodynamics
efficiency than any other wing. On the other hand, as
proceeding our experiment we fabricate model wing
of F-22 raptor and also F7 BG wing to analyze the
practical result of supersonic aircraft flight in nature.
The wing may have a constant or anon-constant cross-
section across the wing.
There are two ways for airfoil selection. They are:
1) Airfoil Design
2) Airfoil section
2.5 BOUNDARY CONDITIONS:
The Simulation was ran using these parameters and
the wind tunnel testing as well. Fluid (Air) was
assumed incompressible and the flow was taken
laminar.
Fluid : Air
Temperature : 298.2 K
Pressure : 101325 Pa
Air Velocity : 4.7 m/s
Air Density : 1.15 Kg/m3
Surface Area : 16074 mm2 or 0.016074 m2
Prototype Material : Beech Wood (Gamahr)
Proceedings of the
International Conference on Mechanical Engineering and Renewable Energy 2017
(ICMERE2017) 18 – 20 December, 2017, Chittagong, Bangladesh
ICMERE2017-PI-113
3. RESULTS & DISCUSSION
3.1 Lift to Drag Ratio:
The higher value of L/D ratio which is known as
the Aerodynamic Efficiency of a wing is the most
desirable and preferable factor for any aircraft wing
design. The value of Lift to Drag ratio can be increased
either by increasing the value of lift or lift coefficient
of corresponding wing or by decreasing the value of
drag or drag coefficient of corresponding wing but in
case of an aircraft design the lift directly depends on
the weight of an aircraft and the drag depends upon the
aerodynamic design of aircraft and its wings. For
finding the almost accurate values of related wing and
airfoil we done our project in ways. As we said earlier
that one of these is theoretical analysis like using
simulation software (SOLIDWORKS) and the other
one is practical analysis which is WIND TUNNEL
testing. All these project work were done by using
above boundary conditions. [3]
Table 1: Aerodynamic Efficiency (L/D) of Wings and
Airfoil (Experimental)
Table 1: Aerodynamic Efficiency (L/D) of Wings and
Airfoil (Experimental)
From the Table 1 and 2 values showing the different
aerodynamic efficiency and various characteristics of
those eight airfoil and wing. The project was done in 6
consecutive angle of attack that showing upper portion
of the two tables. From the table we can see that the
maximum of L/D is (for Experimental= 4.3295) which
belong to model MIG 29 wing at 150 AOA (Angle Of
Attack) & (for simulation= 3.526379) which also
belongs to model MIG 29 wing at 100 AOA. As we see
from the table 1 and 2 both experimental and
simulation analysis model MIG 29 wing shows the
better aerodynamic efficiency.
3.2 Drag Coefficient:
The drag force works in the converse direction of
the moving object in a medium of a fluid. It not only
opposes the motion of an object in a medium of fluid
but also reduces its lift. The drag depends on the
density of the fluid, velocity of flowing fluid or an
object, compressibility and viscosity of flowing fluid
or a fluid around a moving object and the size and
shape of the object. The Coefficient of Drag is a
dimensionless quantity, used to evaluate resistance of
a moving object in a fluid. [3]
The Drag or co efficient of Drag is the dimensionless
quantity, used to resistance moving object in a fluid.
Where, D is the Drag force (N), ρ is the density of
fluid, V is the flow speed of fluid and S the area of
wing.
Table 3: Drag forces of Different Wing and Airfoil at
different AOA (Experimental)
Proceedings of the
International Conference on Mechanical Engineering and Renewable Energy 2017
(ICMERE2017) 18 – 20 December, 2017, Chittagong, Bangladesh
ICMERE2017-PI-113
Table 4: Drag forces of Different Wing and Airfoil at
different AOA (Simulation)
As we know that in aircraft movement of flying
stability of insect and bird there are four basic force
acting on those flying body. Where Lift force counter
the weight of the body thrust force counter the drag
forces of aircraft body. Proper equivalence of these
four forces the aircraft gain stability and move
forward. So, for finding the better one wing or airfoil
we must concern about that it must have low drag
coefficient with respect to much higher lift coefficient.
From the table 3 and 4 we can see that the minimum
drag is (for Experimental= 0.001) which belong to
NACA 64A012 mod airfoil at 50 AOA and (for
Simulation= 0) which also belong to NACA 64A012
mod airfoil at 00 AOA. In this drag forces analysis the
model wing of NACA 64A012 mod airfoil showing
good wing design performance.
3.3 Lift Coefficient:
Lift is a mechanical aerodynamic force that is
generated by a solid object passing through a fluid
and this force opposes the weight of flying object
and hold it in the air. It is a vector quantity and it
acts through the center of pressure of the flying
object. The lift is generated by the difference in
velocity of flying object and fluid, around that flying
object. It takes no difference whether the object is
passing through the fluid or the fluid is flowing over
an object. [3]
Lift force is also a non-dimensional force.
Coefficient of Lift is known as CL
Where, L is the Lift force (N), ρ is the density of fluid,
V is the flow speed of fluid and S the area of wing.
Table 5: Lift forces of Different Wing and Airfoil at
different AOA (Experimental)
Table 6: Lift forces of Different Wing and Airfoil at
different AOA (Simulation)
As we mentioned earlier the basic four forces of an
aircraft or flying body. But the lift is the most
important and useful force of wing or airfoil and while
designing of an efficient wing maximum lift is the
prime factor to considered. A better wing or airfoil
should have maximum or moderate lift generating
capability. From the table 5 and 6 we can see that the
maximum lift is (for experimental= 0.18) which
belong to model F22 raptor wing at 150 AOA and (for
Simulation= 0.34258) which belong to F7 BG model
wing at 150 AOA. Finding different wing max lift
criteria may be bemused us. As we see the table, both
of those wing are showing better lift criteria at
different AOA.
3.4 Theoretical lift force comparison:
Aerodynamic forces result from the pressure
distribution over the surface. One useful way to
evaluate the aerodynamic forces is to use pressure
taps to record the distribution and to integrate the
distribution to find the net force. For lift this
integration is concerned with the pressure distribution
in the vertical direction, while for drag the horizontal
pressure distribution is important. We can see from the
tapping point of the wing surface that how the surface
Proceedings of the
International Conference on Mechanical Engineering and Renewable Energy 2017
(ICMERE2017) 18 – 20 December, 2017, Chittagong, Bangladesh
ICMERE2017-PI-113
“pushes back” with a force against the pressure, which
always acts normal to the surface.[4] Surface curvature
is important two mechanisms are used to generate Lift.
The first is an asymmetric profile (about the chord –
defined in previous slide). This is often used for
subsonic flight applications. The second is to incline
the airfoil at an angle relative to horizontal, which is
usually the “relative wind angle”. For low values of
this angle (angle of attack) the flow remains
attached on both surfaces. For higher angles of
attack separation occurs that increases drag and
reduces lift. Eventually, the airfoil (and vehicle!)
reaches a stall condition, where the pressure
distribution on the top and bottom are equal.[5] As we
proceeding our project work firstly we calculate the
experimental value that we get from wind tunnel
manometric pressure reading at different angle of
attack 00, 50, 100, 120, 140, 150 respectively. By
integrating the corresponding upper and lower
pressure difference finally we aggregated the specific
theoretical lift for those wing or airfoil.
Table 7: Different Theoretical of lift Different Wing
and Airfoil
From the above table we can see that F 7 BG has the
maximum theoretical lift (0.0765 N/m2) and relative
worse wing performance is given by the model
mosquito wing (0.005 N/m2).
4. CONCLUSION
Wing is the part and parcel of aircraft flying. More
accurate shape and size of airfoil more stable in flying
and clearly showing aerodynamic characteristics.
Without wing an aircraft is nothing but a piece of
metal. Wing is the main part of an aircraft that create
lift with which those aircraft fly in air. Also stability
of aircraft this wing portion can play an important role
to maintain this. How long the aircraft will be and how
much load an aircraft can carry that is only depends on
the wing shape and size. This is why different aircraft
has different wing shape according to their purpose.
We used eight different wing and airfoil. Three of
those wing F-22 raptor, F-7 BG & MIG 29 except
Supermarine Spitfire aircraft the other three aircraft
are supersonic 4th generation combat aircraft and
Spitfire is the sonic combat aircraft used World War
II. We also know that Fly’s has great ability to fastest
flight and Dove has more stable, steady flight and
sharp maneuverity during flying. Our project work is
to analyze those characteristics wing and airfoil’s lift
force, drag force and aerodynamic characteristics
during flight. From the theoretical and practical
analysis we found out that the supersonic combat
aircraft wing like model wing of F22 raptor. MIG 29,
F7 BG and NACA 64A012 mod airfoil showed better
aerodynamic characteristics during higher AOA
(Angle of Attack). On the other hand, the left model
wing that showed different results but not as expected.
Our project work is based on some practical theory
which may vary in practical wing experiment. Since
some error may found out because of shape error of
wing design and tapping pressure leakage and
backlash error of wind tunnel.
5. REFERENCES
[1] howthinsfly.si.edu/aerodynamics
[2] http://en.wikipedia.org/wiki/Aeodynamic_force
[3] An aerodynamic comparative analysis of airfoils
for low speed aircrafts/ Sumit Sharma
[4] naca.central.cranfield.ac.uk/reports/arc/r/2884.pdf
[5] www.dtic.mil/dtic/tr/fulltext/u2/b805722.pdf