**Ninth standard configuration (double circular arc cascades at different
flow conditions)**

The ninth standard configuration is a continuation of the eighth, but includes both thickness and camber effects. The geometry of the blades was proposed by Dr. J. M. Verdon from United Technologies Research Center (Fig. 3.9.1). At the present time it is proposed to keep the originally defined 21 aeroelastic sample cases for further studies (Table 3.9.1). However, it has been noted by the calculations done up to now that the high reduced frequency (k=1.0) gave some unexpected numerical problems which should not be the main purpose of the investigation. Furthermore, this high reduced frequency (based on half-chord) is not of extreme practical interest today. The same configurations are thus proposed, as sample cases 22-42, at the lower reduced frequency of k=0.5. The results presented are, as far as the authors' are aware of, all presented with the incompressible dynamic pressure, (r-_•v-_2/2), as non- dimensionalized value. Among others, Whitehead [1990], Li et al [1990], Huff [1989] and Verdon [1989a] have presented numerical results on unsteady flow through vibrating DCA cascades, and Buffum and Fleeter [1989a,b, 1988] and Giordano and Fleeter [1990] have presented experimental data. The conclusions to be drawn are that promising results exist on this standard configuration, but that some unexplained effects still exist. The agreement between different prediction models is usually not as good as one would wish when the inlet flow Mach numbers are high or the blade thickness non negligible. Symmetric/flat-bottomed circular arc profiles Equation: sgn ( H ) = ± 1 for H > 0 / H < 0; ( )+ = upper surface; ( )- = lower surface Maximum thickness at x = 0.5 d = 0.01 - 0.1 c = 0.1 m t = 0.75 g = 45o, 60o camber = 0o (for symmetric profiles) i = 0o (for M1 < 1. ) a = 2.0 o M1 = variable ( 0.0 -> 1.5) k = 1.0 s = 90o Vibration in pitch around (xa,ya) = (0.5, camberline)