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 7.31) with the onset of transition location computed by
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 enmethod 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 a 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
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