SIMULATING A FLOW OVER AN NACA AIRFOIL

• SIMULATING A FLOW OVER AN NACA AIRFOIL

In this report, a flow over a NACA airfoil has been simulated at the different angle of attack. Our main aim was to determine and compare the drag force ( X-direction ) and the lifting force ( Y-direction ) on the airfoil at the different angle of attack ( 0,2,4,6,8,10). The simulation was done using SolidWorks flow simulation.

Geometry Creation –

The co-ordinates points of the curve was downloaded from the database link provided. 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. Just close the loop at the end using line command. 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).To give this angle of attack to the geometry we have to rotate this geometry. Use rotate entities for rotating at different angles.

Extrude up to 0.2 m ( this is same for all the cases ) and save.

Starting with the flow Simulation –

Create a new wizard for every case. Use the default unit system. Next, select the eternal flow as we are doing external flow analysis. This 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. we are taking air as our working fluid medium. Next, we have to give velocity for this air-flow in the x-direction with the magnitude of 600 m/s.

Computational domain –

We are going for 2-d simulation in the XY plane. Here is an example for the computational domain for the angle of attack 10 degree

Meshing and goals -

The basic mesh was looking good so no changes were made. But we have to refine cells at the extruded surface which is 0.2 m long. So to do this we have to add the local mesh. (Select the surface -refining level (3).In this study, we are mainly focusing on the drag and lift forces so we have insert global and surface goals for this.

we can see in the picture below meshing and the goals.

now we are ready to run our simulation so hit run.

RESULTS -

(meshing is not shown because we can\'t see anything in the cut plot)

{notations for graphs and plot results -

case 1 {1} - angle of attack 0 degree

case 2 {2} - angle of attack 2 degree

case 3 {3} - angle of attack 4 degree

case 4 {4} - angle of attack 6 degree

case 5 {5} - angle of attack 8 degree

case 6 {6} - angle of attack 10 degree

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 we selected for local mesh

sg force y - lift force overall on the extruded surface which we selected for 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 -

Goals plot results -

Case 3] Angle of attack 4 degree -

pressure cut plot -

Velocity cut plot -

Goals plot results -

Case 4] Angle of attack 6 degree -

pressure cut plot -

velocity cut plot -

Goals plot results -

Case 5] Angle of attack 8 degree -

pressure cut plot -

velocity cut plot -

Goals plot results -

Case 6] Angle of attack 10 degree -

pressure cut plot -

velocity cut plot -

goals plot results -

Comparison and 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 also 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 in subsequent cases but the only increase frictional drag force we can see is when we 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.s

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.

And overall we can see the increase in the size of wake region as the angle of attack increases. We can see the change in the position of the stagnation point.