Flow over an airfoil

Aim :

1. A flow over a NACA0017 airfoil has been simulated at the different angle of attack.
2. Determine and compare the drag force ( X-direction ) and lifting force ( Y-direction ) on the airfoil at the different angle of attack (0,2,4,6,8,10 deg).

Introduction :

An airfoil is the cross-sectional shape of a wing, blade or sail. An airfoil-shaped body moving through a fluid produces an aerodynamic force. The component of this force perpendicular to the direction of the motion is called lift. The component parallel to the direction of the motion is called drag.

In aeronautics, a chord line is the imaginary straight line joining the leading edge and trailing edge of an airfoil.

Procedure :

1. The co-ordinate points of the curve was downloaded from the database link provided.
2. We used xyz curve to create the airfoil shape. ( insert – xyz points – browse – select the file(txt format)- open – ok ). Now the airfoil shaped curve is formed.
3. Just closed the loop at the end using line command.
4. At this point, the angle of attack is 0 degree. We have 5 more case with an angle of attack (2,4,6,8,10).
5. To give the angle of attack, rotate the geometry by using rotate entities.
6. Extrude up to 0.195m for all the cases and save.

Starting with the flow simulation –

1. Create a new wizard for every case. Use default unit system.
2. Select external flow and the study will be time dependent. We will be performing the experiment for the total of 5 sec and the time step will be 1 sec.
3. Air is the working fluid medium. Give velocity for the air-flow in the X-direction with the magnitude of 600m/s.

Computational domain –

We are going for 2D simulation in the XY plane.

Meshing and Goals –

1. The basic mash is given. But we have to refine cells at the extrude surface which is 0.195m long. To do this, add local mesh.
2. In this study , we are mainly focusing on the drag force and lift force. So we have insert global and surface goals for this.

Now we ready to run the simulation.

Results :

Case 1 – angle of attack 0 degree

Case 2 – angle of attack 2 degree

Case 3 – angle of attack 4 degree

Case 4 – angle of attack 6 degree

Case 5 – angle of attack 8 degree

Case 6 – angle of attack 10 degree

Goals are -

GG force X – drag force overall on the body

GG force Y – lift force overall on the body.

GG friction force X – frictional drag force overall on the body.

GG friction force Y – frictional lift force overall on the body.

SG force X – drag force overall on the extruded surface which is selected for the local mesh.

SG force Y – lift force overall on the extruded surface which is selected for the local mesh.

Case 1 : Angle of attack 0 degree

Pressure cut plot -

Velocity cut plot –

Goals plot results –

Case 2 : Angle of attack 2 degree

Pressure cut plot –

Velocity cut plot –

Goal plot results –

Case 3 : angle of attack 4 degree

Pressure cut plot –

Velocity cut plot –

Goal plot results –

Case 4 : angle of attack 6 degree

Pressure cut plot –

Velocity cut plot –

Goal plot results –

Case 5 : Angle of attack 8 degree

Pressure cut plot –

Velocity cut plot –

Goal plot results –

Case 6 : Angle of attack 10 degree

Pressure cut plot –

Velocity cut plot –

goal plot results –

Conclusion :

1) Angle of attack vs force (X)

So we can see that as the angle of attack increases, the drag force on the body also increases.

2)Angle of attack vs force (Y)

So we can see that as the angle of attack increases, the lift force on the body increases.

3) Angle of attack vs frictional force (X)

So we can see that as the angle of attack increases, the frictional drag force on the body decreases. ( except in the transitioning from case 2 to 3).

4) Angle of attack vs frictional force (Y)

So we can see that as the angle of attack increases, the frictional lift force on the body decreases.

5) Angle of attack vs surface force (X)

So we can see that as the angle of attack increases, the drag force on the surface also increases.

6) Angle of attack vs surface force (Y)

So we can see that as the angle of attack increases, the lift force on the surface also increases.