The Transonic Flow Field of an Axial Compressor Blade Row

The general three-dimensional theory for compressible flow through axial compressor blade rows' 2 is applied to transonic cases. Because of the occurrence in the transonic range of acoustic resonance, the theory is modified to include first-order viscous and heat-conduction effects. This approach is adequate to bring most transonic compressor problems within the realm of linear treatment. Numerical examples of the behavior of a transonic blade row are presented and discussed. The results indicate a smooth transition from the subsonic to the transonic, or mixed-flow, regimes— i.e., the degeneracy encountered in two-dimensional transonic applications of the small-perturbation theory is completely absent. At the same time, the results emphasize the failure of any strip theory, or "blade-element," approximation in the transonic range and thereby cast serious doubt upon the usefulness of transonic cascade studies.