Challenge

Week 7 - Minor Project

Aim

○5, 10, 15 angle of attack

Domain

Domain was created in ICEM cfd and the mesh sizes of cell near the airfoil walls is varied for Subsonic and supersonic cases since there is variation in velocities
For subsonic case the y+ is set to 8 and for supersonic it set to 4
Hence the the first layer thickness for subsonic is set to 3.5e-5 and for supersonic case it was set to 3.8e-6 metres

Setup

For subsonic flow the pressure based calculation is selected
the turbulance model is K-omega
Air density is changed to 2.131 kg/m^3
Pressure is set to zero in referance values
The Inlet boundary condition is given as Velocity-inlet type for domain_ff so that the velocities can be entered in components mimicking the angle of attack
For X velocity , the velocity is multiplied with Cos of angle of attack and for the y velocity it multiplied with sin of angle of attack
Also the component values in report definitions is also changed as well, for lift plot the x component is the cos of angle of attack and y component is sine of angle of attack for lift it is vice versa
For supersonic flows, the solver is set to density based since its compressible

Outputs

Subsonic flow

5 degree

10 degree

15 degree

Supersonic flow

5 degree

10 degree

15 degree

Graphs

Subsonic

Drag coefficient

Lift coefficient

Supersonic

Drag coefficient

Lift coefficient

Observations

There was a significant decrease in lift when the angle of attack is increased to 15 degree as it leads to creation of more wake region thus increasing the drag too, hence the phenomenon called stalling can occur in these conditions
This issue is fatal at supersonic speeds
The wake regions can be observed in the velocity contours as well as in pressure contours, it is clear that an angle of attack of 15 degree created more wake region
A varyng behaviour in the output plotes at angle of attack of 15 degree is observed in supersonic flow

Conclusions

Done the simulation at subsonic and supersonic cases
Calculated the forces on walls
Extracted Velocity and pressure contours
Plotted the coefficients of drag and lift against angle of attacks on both the cases

Ship work like this
in your own course.