Test Case 6
This test case is for the same airfoil except that the airfoil is assumed to undergo translational
harmonic motion with   6o , Rc  3  106 , x  0.1 , y  0.3,   10 for two reduced
frequencies   0.025 and 0.25.
Figure 10.14. Variation of (a) lift coefficient cl and (b) velocity translation (ux,uy) for
translational harmonic motion with   0.025
Figure 10.15. Variation of (a) lift coefficient cl and (b) velocity translation (ux, uy) for
translational harmonic motion with   0.25
Figures 10.14 and 10.15 show cl, ux and uy as a function of cycle for both reduced frequencies.
As can be seen, in both cases, the quasi and unsteady flow assumptions agree very well with
each other and the viscous lift coefficients differ from those given by the inviscid flow theory.
We note that the inviscid flow solutions were obtained for two cycles in order to reduce the
steady-state effects and the viscous flow solutions were started at the end of the first cycle.
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