Individual assignment #2: Flow around an airfoil

The goal of the exercise is to check the compliance of an airfoil to an technical application using CFD simulation. The airfoil and the technical application can be chosen by You.

The geometrical data of the airfoils can be downloaded from the webpage http://aerospace.illinois.edu/m-selig/ads/coord_database.html (check that, the measurement results of the airfoil can be found in site a http://www.airfoildb.com/foils/list). To load the data file in ICEM CFD, the first row must contain the point number and number of the connecting lines (1), the format of the data file must be tab separated. (Fig. 1) The trailing edge of the airfoil can be approximated by an semicircle. (Fig. 2) The convergence of the calculations should always check with the change of physical properties.

Figure 1: sample to the data file

Figure 2: Trailing edge

Task 1 (5 points)

Create a computational domain as seen in Fig.3., take care about adequate distance of the inlet and outlet boundary. Create a C type mesh with 3 different element number and a fine resolved boundary layer around the airfoil. To compare the results the aspect ratio and angles of the cell surfaces must be the same in any chosen point. By the choice of the mesh element numbers, respect the applicability of the Richardson extrapolation!

Figure 3: The computational domain.

Task 2 (5 points)

Make a grid sensitivity investigation. The chosen fluid should be incompressible air with density of 1 kg/m³. The inlet velocity should be 1 m/s in x direction, with the choose of the viscosity set the Reynolds-number to 100000 (the characteristic length is the chord of the airfoil, 1 m)

Task 3 (6 points)

Visit the http://www.airfoildb.com/foils/list website, then simulate the case with the maximum c_l/c_d ratio using 3 different turbulence model. (the roughness high should be 0 m, the inlet turbulence intensity is 1%, the characteristic length of the inlet turbulence is 0.25 m). Compare the measured and calculated lift and drag coefficients and select the most suitable turbulence model for solving the problem. To calculate the dimensionless quantities use 1 m² reference surface.

Task 4 (4 points)

Perform calculations with the chosen turbulence model for 4 different Reynolds number or angle of attack which occurs in your technical application. If necessary (i.e. stall) switch to transient simulation. Compare the pressure and velocity fields and the pressure distributions along the pressure and suction side for the different cases.

Task 5 (5 points)

Summarize your work in a .ppt format document and upload to the location specified by your instructor.