2. Experimental facilities and data processing
Fig. 1 depicts (a) constructional details of present twin-pass test channel with the two opposite sidewalls configured by skewed sinusoidal wall-waves and another two opposite endwalls roughed by 45 ribs. The two pairs of skewed sidewall waves and 45 end- wall ribs are both in-line arranged. The details of the endwall rib floor and the undulant sidewall are illustrated by Fig. 1(b). The three test channels have the same channel width (W) of 40 mm but different channel heights (H) of 20, 40 and 80 mm, giving rise three channel width-to-height (Aspect, AR) ratios of 0.5, 1 and 2. The corresponding channel hydraulic diameters (d) for the three test channels of AR = 0.5, 1 and 2 are 47, 36 and 25 mm