Interim Report Zain

DESIGN OF THE WINGTIP(INTERIM REPORT)

Tile of the project:

DESING OF THE HELICAL WINGTIP.

Introduction:

The project, Design of the wingtip, is a unique project that will deal with the design of the wingtip. The project will deal with all the various aspects related to the speculative and analytical factors required to study the design of the wingtip and also to design the wingtip. There are various types of the wingtips that are used on the aircrafts like the squared-off wingtip; rounded wingtip; tip tanked wingtip; sails wingtips; winglets; etc. Out of all of these and various other designs of the wingtips, winglets are the type of the wingtips that are extensively used in this eon of the aircraft industry. Though the design of the wingtips varies, the aim of the wingtips is always the same that is to reduce the drag of the aircraft by altering the flow of the air near the wingtips. Wingtips are also used to improve the aircraft handling physiognomies and also used to augment the safety of the aircraft during its flight.

The winglets are used so widely that it has many other shapes that are used in different aircrafts according to the aircrafts configuration and design. Some of the common designs used are the wingtip fences; ranked winglets and blended winglets. This project shall deal with the design of the winglet with a helical shape. The helical shape winglet is a most unusual type of winglet that is used. Hence, for this very reason it becomes a supreme theme for the final year presentation as it is unfamiliar and with high levels of complications to be faced.

The helical shaped winglet shall be designed for the military support aircraft specifically in my case that is Hercules C-130 which is a fast military transport aircraft. The main characteristics that are to be considered about the aircraft are:

Autonomy: 5,000 km; Lightweight approx.: 5 tons; Maximum high: 10,000 m; Cruising speed approx.: 550km/hr.

ZAIN ANSARI(S09002954) Page 1


This project will be a part of the group project that was started by the 2010 batch students in supervision of Dr. Zourbir. They had designed the fuselage, wing and the tail of the same aircraft. And now under the supervision of the same professor I will conduct the individual project that is to design of the wingtip of the aircraft HERCULES C-130 and ultimately it will add in as design of another important part of the aircraft.

The design of the helical shaped wingtip will have certain main milestones that I have to undertake and get it done by doing a vast research and stacks of use to the program GAMBIT and FLUENT. Some the milestones that can be briefly specified are as follows:

Study the section corresponding to the wingtip; To design the wingtip section in 3-D CFD-program; Studying the 3-D wingtip from Gambit Program; Perceptive the outcomes achieved from Fluent Program.

To design the helical shape winglet, I have to design the winglet section in the Gambit and Fluent Programs. The Gambit program will help me make the winglet section in the 3-D section from the 2-D section. This helps in visualizing the winglet with various images and graphics which ultimately helps in achieving closest and accurate results. This 3-D wingtip section will then imported to the Fluent to get all the various results.

AIM OF THE PROJECT:

The aim of the project is to design the HELICAL SHAPED WINGLET;

The design of the winglet shall be done in the Pro-Engineer, Gambit and Fluent Environment ;

The design shall be finally tested in the wind tunnel which is in the university’s laboratory for its authenticity;

It shall that be compared with another normal wingtip to justify is advantages and effectiveness.



OJECTIVES/PROJECT PLAN OF THE PROJECT:

Obtain a specific shape of the winglet and aerofoil; 3-D modeling of winglet in Pro-Engineer; Import model in Gambit and Mesh it; Testing the model in Fluent to obtain various results

for different ANGLE OF ATTACKS; Test and Analyse the model in WIND TUNNEL; To compare the design with the normal wingtip.

BACKGROUND:

AERODYNAMICS:

As I am making a project that deals with aerodynamics field of the science of engineering, I have to understand all the aspects and basics of the aerodynamics. Aerodynamics is the study of forces and movements that result in objects that pass through the medium of air. To put the definition in precise scientific words we can put it as “the branch of fluid mechanics that studies the actions appear in solid bodies when there is relative motion between these and the fluid that surrounds” or “a branch of dynamics that deals with the motion of air and other gaseous fluids and with the forces acting on bodies in motion relative to such fluids”. All the objects like commercial aircrafts, rockets or even an apple falling from the tree requires a complete study of aerodynamics to know it true working. An object has decent aerodynamics when its geometry provides a least opposition to forward and the air that ambiances it does not become very tempestuous. To study any problem related to the aerodynamics it is required to calculate various properties of the aerodynamics such as pressure, density, speed and temperature depending on the case that is to be studied.



AERODYNAMIC PROPERTIES AND THEIR DEFINITIONS:

Aerofoil:A device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight OR A part or surface, such as a wing, propeller blade, or rudder, whose shape and orientation control stability, direction, lift, thrust, or propulsion.

Chord:A straight line joining the trailing and leadingedges of an airfoil section.ORAn imaginary line connecting the leading edge to the trailing edge of the wing aerofoil section.

Leading Edge:The point that first hits the airflow is known as the leading edge. It is also known as the most radical point in the wing profile.

Trailing Edge:It is the point that is behind the wing profile.

Upper Surface:The upper surface denotes the upper side of the wing profile. The flow of the velocity is greater than the lower surface of the wing profile. The pressure is low as well in the upper surface.

Lower Surface:The surface is the lower surface of the wing profile. The velocity is less than it is found on the upper surface. Also the pressure is high on the lower surface.



Aspect Ratio:The aspect ratio of a wing is the length of the wing compared with the breadth (chord) of the wing. A high aspect ratio indicates long, narrow wings, whereas a low aspect ratio indicates short, stubby wings. Also the aspect ratio is an airplane's wing's span divided by its standard mean chord (SMC). It can be calculated more easily, however as span squared divided by wing area.

Angle of Attack:

The acute angle between the chord of an aerofoil and a line representing the undisturbed relative airflow. The angle of attack should not be confused with the pitch angle or attitude of aircraft, which are angles relative to the horizontal while the angle of attack is in respect to the relative airflow. It is referred to also as alpha (α).

Angle of attack is the angle between the wing chord plane and the relative air flow.

PHYSICAL JUSTIFICATIONS:

Forces that affect the aircraft:An aircraft in flight is in the interior of an unremitting encounter of forces. The conflict of these forces is the key to all manoeuvres accomplished in the air. There is nothing



enigmatic about these forces—they are definite and recognised. The course in which each acts can be planned. The aircraft is designed to take gain of each force. These forces are lift, weight, thrust, and drag.

Lift Coefficient:The lift coefficient is a number that aerodynamicists use to ideal all of the intricate enslavements of shape, inclination, and some flow conditions on lift. This equation is basically a reorganization of the lift equation where we solve for the lift coefficient in terms of the other variables. The lift coefficient Cl is equal to the lift L divided by the quantity: density r times half the velocity V squared times the wing area A.

Cl = L / (A * .5 * r * V^2)

The quantity one half the density times the velocity squared is called the dynamic pressure q. So

Cl = L / (q * A)

The lift coefficient then expresses the ratio of the lift force to the force produced by the dynamic pressure times the area.

Drag Coefficient:The drag coefficient is a number that aerodynamicists use to ideal all of the intricate enslavements of shape, inclination, and flow conditions on aircraft drag. This equation is merely a reorganization of the drag equation where we elucidate for the drag coefficient in terms of the further variables. The drag coefficient Cd is identical to the drag D divided by the quantity: density r times half the velocity V squared times the reference area A.

Cd = D / (A * .5 * r * V^2)

The quantity one half the density times the velocity square off is called the dynamic pressure q. So



Cd = D / (q * A)

The drag coefficient then couriers the ratio of the drag force to the force fashioned by the dynamic pressure times the area.

Lift to Drag Ratio:

The lift-to-drag ratio of an aircraft is the ratio of the lift force to the drag force. This number is dimensionless, and is commonly abbreviated to L/D, pronounced "l over d".

The L/D of an aircraft is one of its most significant design variables. The value of L/D, in the circumstance of commercial aircraft, is typically getting the most out of, which results in the greatest aerodynamic proficiency. This means better fuel economy and thus lower costs. The ratio of the



coefficient of lift to the coefficient of drag of an aerofoil at various angles of attack. It is a amount of the aerofoil’s proficiency. The angle of attack that gives the best lift-by-drag ratio is the most proficient angle of attack. In normal aerofoils, this normally parallels to 4°.

Flow systems:All the fluids are categorized into two chief groups which are frequently known as the laminar flow and the turbulent flow. The type of the flow should be known as it affects the design and functioning of the object that will be functioning in the fluid envelope. For example the amount of fluid friction regulates the amount of energy required to be sustained to acquire the preferred flow, this also depends upon the mode of the flow. This sometimes in some cases is an imperative factor to be known.

Turbulent Flow:Turbulent flow is characterized by the irregular movement of particles of the fluid. There is no definite frequency as there is in wave motion. The particles travel in irregular paths with no observable pattern and no definite layers. In turbulent flow vortices, eddies and wakes make the flow unpredictable. Turbulent flow happens in general at high flow rates and with larger pipes. Shear stress for turbulent flow is a function of the density - ρ.

Laminar Flow:Laminar flow generally happens when dealing with small pipes and low flow velocities. Laminar flow can be regarded as a series of liquid cylinders in the pipe, where the innermost parts flow the fastest, and the cylinder touching the pipe isn't moving at all.Shear stress depends almost only on the viscosity - μ - and is independent of density - ρ.



Theory of the Helical Wingtip:

The invention concerns a device having the shape of a spiral and/or helical slot cylindrical cavity for reducing induced drag, tip vortex and to increase lift-drag ratio.

The device securely fixed to the wing tip or securely articulated to said wing tip, can be adapted to all profiles, in particular to aeroplane wings, to gliders, to helicopter blades and to driving, pusher or propelled airscrew tips such as wind turbine blades or for craft such as boats or submarines using lift or steering in their three-axis movement, vertical, horizontal and yawing.

For existing rates of efficiency, the invention enables the use of low traction systems, longer and faster trips while consuming less energy or while producing more as with wind turbines for example, the use of greater loads, the increase and approach of aerodrome or airport transit/landing/take-off traffic more safely.

WORKING PRINCIPLE OF THE HELICAL SHAPED WINGLET:

Minix works on the principle that the vortex will hit the wing at exactly the same distance from its tip as the measurement of thickness of the wing.

It is designed to allow the vortex to escape through slits in its tube-like body as pressure increases.

The result, the vortex dissipates into a linear flow through an opening at the back of the winglet.

TIMELINE AND PROFRESS OF THE PROJECT:



The time line of the project can be clearly seen in the Gantt Chart that is given below. It has been made by considering the objectives of the Project as stages of the progress of the project that has to be done. There are many different types of things that are being worked on in each stage. At the moment are work has reached the fourth stage where I am modelling the wingtip.

Above is the Gantt Chart which briefly represents the stages in which the project shall be carried out.

Working done it Gambit and Fluent programs for the design of the project:

Step1:Created Geometry in Gambit program:

In an external flow such as that above an aerofoil, I have defined a far field boundary and mesh the region between the aerofoil



geometry and the far field boundary. I have placed the far field boundary well away from the aerofoil since I have to use the ambient conditions to define the boundary conditions at the far field. The farther we are from the aerofoil, the less effect it has on the flow and so more accurate is the far field boundary condition. The far field boundary that I will use is the line ABCDEFA in the figure above. ‘C’ is the chord length.Import EdgeTo specify the airfoil geometry, I have to import a file containing a list of vertices along the surface and have GAMBIT join these vertices to create two edges, corresponding to the upper and lower surfaces of the airfoil. I have then split these edges into 4 distinct edges to help us control the mesh size at the surface.The following is the naca4412.dat file that will be used:

255 2

0 0 0

-0.00019628 0.001241474 0

-0.000247836 0.001759397 0

-0.000275577 0.002158277 0

-0.000290986 0.002495536 0

-0.000298515 0.002793415 0

-0.000300443 0.00306332 0

The first line of the file represents the number of points on each edge (255) and the number of edges (2).

The first 255 set of vertices are connected to form the edge corresponding to the upper surface; the next 255 are connected to form the edge for the lower surface.

The chord length, c for the geometry in naca4412.dat file is 1, so x varies between 0 and 1.

After using these values and using some functions and steps like Geometry Create in the Gambit program, we obtain the following aerofoil:



After this I will now create the boundary field. To do so we need to following certain steps like creating vertices and joining them appropriately to form edges.: we use the following coordinates to create the vertices:

Label x y z

A c 12.5c 0

B 21c 12.5c 0

C 21c 0 0

D 21c -12.5c 0

E c -12.5c 0

F -11.5 0 0

G c 0 0

After using steps from operation command in Gambit to create the vertices we get the following:



Similarly, we create the edges of the aerofoil and obtain the following:

Step:2

Mesh the Geometry:

I have mesh each of the 3 faces separately to get the final mesh. We need to define the point distribution for each of the edges that form the face i.e. I have to first have to mesh the edges to mesh the faces. The edge mesh parameters we'll use for controlling the stretching are successive ratio, first length and last length. Each edge has a direction as indicated by the arrow in the graphics window. The successive ratio R is the ratio of the length of any two successive divisions.

For edges AB and CG, I have set the First Length (i.e. the length of the division at the start of the edge) rather than the Successive Ratio.

Edges Arrow Direction

Successive Ratio Interval Count

GA and BC Upwards 1.15 45

Edges Arrow Direction First Length Interval Count

AB and CG Left to Right 0.02c 60

With this I have used Gambit functions like operational tootlpad which has Mesh Command Button and obtained the following result:



Repeat the same steps for edges BC, AB and CG with the similar specifications and finally we get the full mesh:

Step:3

Stipulate Boundary forms in Gambit:

I have created the groups of the edges initially and then will form the boundary objects from these groups. Initially, I will group up AF and EF together and by using the command Geometry Command Button in the Operation Toolpad I will form their group as follows:



Similarly, I will follow the same procedure for the rest of them as well.

Now, I will define the Boundary Condition by using the function Zone Command Button in the Operational Toolpad. This function has an option Specify Boundary types which shall be utilized.

After selecting all the appropriate options I have selected the Apply button and in the message block we receive the message that the Boundary Type has been selected. We then save the file.



Step:4

Export and run the data in Fluent Program:

After this we will export the data from Gambit to the Fluent where we have set all the properties as follows appropriately:

Materials; Viscosity; Models-Solver; Energy; Operating Conditions; And Boundary Conditions, etc.

We will then solve it using the following from the solve option of the Fluent Program:

Solution; Initialize; Residual Monitor; Force Monitors;

We also set the reference values and now after setting all the options we can now run the iterations. It is ideal to save the matter first before running the iterations as it takes a long time to give complicated results.

After the iterations run we get the solution/results from it.

Step:5

Examine the results obtained:

We can plot the velocity vectors in the fluent program and following is obtained:



From the diagram it can be seen that the velocity in the upper surface has higher speed than the velocity at the lower surface.

we can obtain the pressure coefficient in the Fluent Program as well and after following certain step in the Program changing the Y Axis function to the pressure we can obtain the following result:

We can also display the pressure contours in the Fluent Program by using commands like display then contours in which we can select pressure and pressure coefficient and then we can obtain the following:



This is the part where we have designed the two dimensional aerofoil till date. This will be used further to create the three dimensional wing. This will also be carried out in the Gambit Program. After obtaining a satisfactory design of the wing, I will then design the helical shaped winglet in Gambit and Fluent. This is once done I will then assemble the helical shaped winglet in the three- dimensional wing which will be obtained in the former stage of the project. And then the comparing stage will start where I will compare the working and efficiency of the wing with and without the helical shaped winglet. This will help us to distinguish and justify the efficiency of the helical shaped winglet.

After this I will compare the helical shaped winglet with the regular winglet of AIRBUS- 380 if time permits.

I have also done a detailed theory research and the designing part has almost finished with the 1st stage which I have described above.

EXPECTED RESULTS IN WIND TUNNEL TEST:

After designing stage I am expecting the following results to be achieved in the wind tunnel test:

Wing without the helical shaped wingtip.



Wing with the helical shaped wingtip.

wing tested without the helical shaped wint tip.

wing tested with the helical shaped wing tip.



wing tested without the helical shaped wing tip.

wing tested with the helical shaped wing tip.

Conclusion and Discussion:

The theory part has been almost completed. And a suitable aerofoil has also been selected that will be utilized to design the wingtip. Also a thorough research has been done on the type of the wingtip that I have to design.There some changes that I would like to mention that have been made till now. Initially it was planned to design the wing and the wingtip in the Pro-Engineer Program and then export the design in Gambit Program and run in further. But, then after the advice of my supervisor and advice of some friends who are well versed with these programs I changed my plan that was initially made. I have now decided to do the complete designing right from the beginning in the Gambit Program itself. Though it is a Complex Program to work with I have yet put efforts to learn it to a level where I can manage to design my helical shaped winglet satisfactorily. Hence,



I am lagging quite a bit behind in my project but will extra effort the project shall be completed in due time as scheduled.


Documents

Interim Report Zain