Test Case 2
The unsteady interactive boundary-layer (UIBL) program can be used for steady and
unsteady airfoil flows. This test case demonstrates its application to steady flows at high
Reynolds numbers (see subsection 7.3.1) with the onset of transition location computed
with Michel’s method, Eq. (7.31), except where the boundary layer separates upstream of
this location, in which case transition is assumed to correspond to the separation point. It
can also be used for low Reynolds number flows provided the onset of transition is
computed with the en-method since in such flows, the transition location is usually inside
the separation bubble (subsection 7.3.2)
Figure 10.2 shows the variation of the lift coefficient with angle of attack for chord
Reynolds numbers Rc of 3X106 and 6 X106 . The calculated results agree well with
experimental data as well as with those computed (see Fig. 7.25a) with the airfoil code
for steady flows described in [1].
Fig. 10.2 Comparison between calculated (solid lines) and experimental values (symbols)
of the lift coefficient. NACA 0012 airfoil, (a) Rc = 3X106, (b) Rc = 6X106