TO SIMULATE THE AIR FLOW OVER NACA AIR FOIL USING SOLIDWORKS

AIM

To calculate the drag and lift force for the following angle of attack (AOA) at 0, 2, 4, 6, 8, 10.

INPUT

INPUT	VALUES
Air foil	NACA0017
Chord length	1m
Velocity	600 m/s in x-direction
Flow type	External flow
Fluid	Air
Time dependent	Total analysis time 5s
	Output time step 1s

BODY OF CONTENT

Introduction

An airfoil or aero foil is the cross-sectional shape of a wing, blade (of a propeller, rotor, or turbine), or sail.

An airfoil-shaped body moving through a fluid produces an aerodynamic force. The component of this force perpendicular to the direction of motion is called lift. The component parallel to the direction of motion is called drag. Subsonic flight airfoils have a characteristic shape with a rounded leading edge, followed by a sharp trailing edge, often with a symmetric curvature of upper and lower surfaces. Foils of similar function designed with water as the working fluid are called hydrofoils.

In fluid dynamics, angle of attack (AOA, α) {\displaystyle \alpha } is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is moving. Angle of attack is the angle between the body's reference line and the oncoming flow. This article focuses on the most common application, the angle of attack of a wing or airfoil moving through air.

In aerodynamics, angle of attack specifies the angle between the chord line of the wing of a fixed-wing aircraft and the vector representing the relative motion between the aircraft and the atmosphere. Since a wing can have twist, a chord line of the whole wing may not be definable, so an alternate reference line is simply defined. Often, the chord line of the root of the wing is chosen as the reference line. Another choice is to use a horizontal line on the fuselage as the reference line (and also as the longitudinal axis).

A symmetrical wing has zero lift at 0 degrees angle of attack. The lift curve is also influenced by the wing shape, including its airfoil section and wing planform. A swept wing has a lower, flatter curve with a higher critical angle.

STEPS OF DESIGNING

Before designing make sure the unit is in meter

1. First download the file of NACA 0017 air foil from the link http://airfoiltools.com/airfoil/naca4digit?MNaca4DigitForm%5Bcamber%5D=0&MNaca4DigitForm%5Bposition%5D=0&MNaca4DigitForm%5Bthick%5D=17&MNaca4DigitForm%5BnumPoints%5D=81&MNaca4DigitForm%5BcosSpace%5D=0&MNaca4DigitForm%5BcosSpace%5D=1&MNaca4DigitForm%5BcloseTe%5D=0&yt0=Plot

2. Then in Solidworks go to file menu and select a new part.

3. Click on insert menu and go to the curve option after that select curve through xyz point. After that one dialog box will be appeared.

4. Click on browse option and open the NACA 0017 file (make sure that the format is in text file.)

After that coordinate is displayed in the dialog box after that click on ok button.

5. Click on sketch option in Front plane choose convert entity option and then select the curve which is display on the screen in order to make sketch of the curve.

6. Now the curve is open at the end, close the end by the help of line command.

7. Now go to move entity option in order to provide the angle.

Select curve as well as line, after that provide the origin point in order to rotate the design with some angle.

8. Now go to the extrude option and give the length of 1m.

STEPS OF FLOW SIMULATION

Before starting flow simulation first enable the flow simulation from the solidworks add ins

1. Go to the WIZARD option to start a flow simulation. After that one dialog box will appear. Write project name which you want to give the name to it. After that click on next.

2. When you hit the next button it asks to set the unit system. For my project i used as SI unit. After that click on next button.

3. After click on next it will ask to define the flow type whether it is external or Internal. My aim is to study outside the Air foil so I used external.

There are several additional features also present like gravity, time dependent etc select the option if required in study. After that hit next button.

I have used time dependent option as mentioned in the figure.

4. After that select the fluid which you want to take in your study and click on add button in order to add the fluid. Here I have used air as a fluid.

5. After that choose roughness of the wall if it has otherwise click on next.
6. After that provide essential details like velocity and click finish button. Here I am taking 600m/s velocity in X-direction.

7. After that your design will be enclosed in the chamber which is our domain of interest as shown in figure below. In order to edit the enclosed box right click on computational domain and choose edit definition option. Here I have given the dimension of CFD domain is

8. To study the flow analysis we need to select the quantity which we need to study.

In order to study the quantity, we need to right click on goal and select insert global goals after that select the quantity which you want to study.

9. Similarly we need to study for the surface goal.
10. In order to provide local mesh right click on mess and select local mess

After that select the surface of the air foil and give local mess according to your specification.

11. Now click on the run option and select new calculation and click ok button to start flow simulation.

12. Solver window will appear. This for the angle of 8 degree.

RESULT

Case 1. When angle of attack is zero

Pressure plot

Velocity plot

Case 2. When angle of attack is two degree

Pressure plot

Velocity plot

Case 3. When angle of attack is four degree

Pressure plot

Velocity plot

Case 4. When angle of attack is six degree

Pressure plot

Velocity plot

Case 5. When angle of attack is eight degree

Pressure plot

Velocity plot

Case 6. When angle of attack is ten degree

Pressure plot

Velocity plot

ANGLE OF ATTACK	AVERAGE DRAG FORCE	AVERAGE LIFT FORCE
0	6949.678	-2.6515
2	7061.049	3403.87
4	7394.667	6637.942
6	7887.149	10157.62
8	8668.192	13378.02
10	9574.516	16776.89

COMPARISON OF RESULTS

Average Drag Force Vs Angle of Attack

Average Lift Force Vs Angle of Attack

Average Lift Force Vs Average Drag Force

CONCLUSION

1. The increase of maximum pressure and maximum velocity are not very much significant when the angle of attack is increase in the air foil.
2. The drag force increases with increase in angle of attack.
3. The lift force also increases with increase of angle of attack.
4. The rate of increment of drag force w.r.t. angle of attack is very small as compared to rate of increment of lift force w.r.t. angle of attack.
5. The drag force is almost negligible and value is close to zero at zero degree of angle of attack because the air foil NACA0017 is symmetric.

REFERENCES

1. Video lecture of skill lync
2. Wikipedia
3. www.airfoiltools.com for NACA0017 air foil