Week 7 - Minor Project
Aim --> NACA 0012 Supersonic/Subsonic flow project.
Incompressible Case (sub-sonic flow M=0.15)
Case-Setup
pressure-based steady-state solver
AOA --> 5,10,15 degree
Velocity --> 52.15 m/s
Refference values
Turbulence model --> K-w SST model
Inlet --> (velocity inlet) Velocity components are specified (x,y component)
outlet --> (pressure outlet (operating pressure condition))
Airfoil --> wall
top and bottom --> symmetry
density --> 2.131 kg/m3
Standard initialization (computing with inlet)
Solver --> coupled scheme with 2nd order upwind turbulence scheme.
flow courant number --> 1
coefficients used for calculating lift and drag
| AOA | Sinθ | Cosθ |
| 5 | 0.0871 | 0.996 |
| 10 | 0.173 | 0.984 |
| 15 | 0.258 | 0.965 |
--> Components of drag and lift are to be taken from the shifted(rotated) plane to the original xy plane with proper sign convensions, if sign-convensions are not properly given the orientation of lift drag vector in 2D space will change and thus give us wrong values.
Results
Case --> AOA = 5 degree
Residual plot
Pressure and velocity contours
Drag and lift parameters
Wall Y+
Case --> AOA = 10 degree
Residual plot
Pressure and velocity contours
Drag and lift parameters
Wall Y+
Case --> AOA = 15 degree
Residual plot
Pressure and velocity contours
Drag and lift parameters
Wall Y+
Comparison Table (Cd,Cl vs AOA)
| AOA | 5 | 10 | 15 |
|
Cd |
0.04 | 0.06 | 0.11 |
| Cl | 0.15 | 0.33 | 0.47 |
Compressible Case (sub-sonic flow M=0.65)
- Pressure based steady-state solver
- pressure far field condition at all boundaries (with infinity mach number and static pressure as input)
- Energy turned on.
- Operating pressure --> 0 Pa.
- density --> Ideal Gas
- Standard initialization (computing with inlet)
- Solver --> coupled scheme with 2nd order upwind turbulence scheme.
- flow courant number --> 1
Mesh
Case AOA --> 5 degree
velcoity --> 272 m/s
Residual plot
lift
The value will converge at around 0.5 lift if we run simulation for long.
drag
Velocity contour
Case AOA --> 10 degree
velcoity --> 272 m/s
Residual plot
lift
drag
Velocity contour
Pressure contour
Temperature contour
Density contour
Case AOA --> 15 degree
Residual plot
lift
drag
Wall y+
Velocity contour
Static Pressure
Turbulent kinetic energy
Temperature contour
Density contour
Comparison Table (Cd,Cl vs AOA) Compressible case
| AOA | 5 | 10* | 15 |
|
Cd |
0.07 | 0.17* | 0.25 |
| Cl | 0.62 | 0.76* | 0.87 |
Conclusion
--> Flow over an airfoil at subsonic and supersonic regime was analysed.