Week 9 - Mini project - Flow over an Airfoil

AIM :

Simulate flow over a 4 digit airfoil i.e NACA 2412 Airfoil.

OBJECTIVE :

We will have to calculate the following,

• Drag co-efficient Vs Angle of Attack
• Lift co-efficient vs Angle of Attack
• Compare the effect of turbulence models on the above two results.
• Make sure that the inlet Reynolds number is 200,000
• Make sure you do above calculations for the following angle of attacks,
  • Angle of attack = 1º
  • Angle of attack = 5º
  • Angle of attack = 10º
  • Angle of attack = 15º

Let us know the what is angle of attack

The Angle of Attack is the angle at which relative wind meets an Aerofoil. It is the angle formed by the Chord of the aerofoil and the direction of the relative wind or the vector representing the relative motion between the aircraft and the atmosphere.

The coefficient of lift is a measure of how much lift the wing can produce and can only be changed by changing the shape of the wing or the angle of attack at which it cuts through the relative wind. We can change the shape of the wing using flaps, slats, or other similar leading and trailing edge devices. We change the angle of attack using our flight controls and, in some cases, power settings.

the pressure over and under the wing decreases as the velocity of the air increases. The pressure differential over the top and under the bottom of the wing generate the aerodynamic force that becomes lift and drag.

Procedure to creating the geometry 

Visit the site to get .DAT file for NACA 2412 Airfoil,

 This are the co ordinates for the creating the geomerty

 

The final geometry will look like this 

This is a setup of a virtual wind tunnel

After the final dignosis 

we can start the case set up

The front and back are 2D . top and bottom are symmetry

Give a calcuated outputs files and export the files to a folder and run in the CIGWIN command 

After the completion Postprocess the results in converge and understand the lift and drag polts

Hear are the result for 1 degree angle of attack

Mesh

Pressure Image of Airfoil

Velocity image of Airfoil

Hear are the result for 5 degree angle of attack

Mesh

Pressure Image of Airfoil

Velocity Image of Airfoil

Hear are the result for 10 degree angle of attack

Mesh

Pressure Image of Airfoil

Velocity Image of Airfoil

Hear are the result for 15 degree angle of attack

Mesh

Pressure Image of Airfoil

Velocity Image of Airfoil

Lift Plot

AOA : Angle of Attack

 Drag Plot

AOA:angle of attack

D: Degree

 This are the plots which are simulated by the different Turbulance module

we simulated 5degree of angle of attack of k omega sst and standard k epsulon module

Drag plots

 Lift polts

Drag co-efficient Vs Angle of Attack

Lift co-efficient vs Angle of Attack

To calculate the Lift co-efficient & Drag co-efficient 

We got a formula

cd = df/(0.5*density*area*v*v)

where cd =  co-efficient of drag

df = drag force 

v = velocity

Same for the Lift co-efficient cf & lf will change thats it.

 by calculating all value we got a plot which we use octave to get it

CONCLUSION 

From the above results, the following observations are made

The converge's steady-state solver is not suitable for this simulation.

The transient case is much more effective and the K omega SST model

calculates the physics better than RNG K epsilon.

AOA 1 Degree,AOA 5 Degree,AOA 10 Degree dos make a small differnce in lift and drag but the15 AOA has huge effect on the airfoil