In order to examine the fundamental characteristics of a corner separation in a decelerating cascade flow, an experimental apparatus was made and the separations around a NACA65 blade in a decelerating channel flow were examined both experimentally and numerically. The two-dimensional calculations show that the NACA65 cascade flow that has 45 deg. of the turning, 1.24 of the solidity and 17 deg. of the stagger angle is similar to the channel flow that has 14 deg. of the stagger angle in terms of the pitchwise blade force. The experimental investigation by the five-hole probe shows that the accumulations of the low energy fluid can be seen around the corner part and the overturning flow due to the secondary flow exists. And, as the periodicity of the blade wake in the pitchwise direction is comparably good, the wake of this channel flow is similar to the wake of the cascade flow for the two pitch portion. PIV measurement showed that the focus-type separation was seen in the momentary streamline along the suction surface of the blade, whereas no apparent separation was seen in the flow along the endwalls. SD diagram consideration showed that the present case on the study was consistent with the relation between the stall indicator S and the diffusion parameter D proposed by Lei et al.
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