Correction of lift coefficient for tandem circular-cascade diffusers

The interaction between two rows of cascades is discussed quantitatively. The lift characteristics of each cascade of a tandem cascade are calculated numerically based on a two-dimensional potential theory, and the result is compared with the lift characteristics of the individual cascades without mutual interaction; then, the correction factors due to mutual interaction are obtained. The performance of a low-solidity circular tandem-cascade diffuser is predicted using those correction factors and compared with experimental results. The blade circulation of each cascade is also evaluated from the measured pressure distribution along the blade surface and compared with the prediction.