Forcing function generator fluid dynamic effects on compressor blade gust response

Abstract

To investigate the fundamental flow forcing function phenomena generating different blade row gust responses, in particular attached and separated flow forcing functions, a series of experiments are performed in an extensively instrumented axial flow research compressor. In these experiments, the gust ratio magnitude is controlled without affecting the forcing function fluid dynamics, i.e., attached or separated flow, thereby enabling a controlled study of the effect of steady loading. Periodic 2-E unsteady aerodynamic forcing functions to the first stage rotor are generated by fundamentally equivalent honeycomb sections and flat plate airfoils, with unsteady linear theory gust requirements considered. Then the resulting rotor blade row gust response is measured over a range of steady loading levels and the gust response data correlated with the appropriate linear theory predictions. These experiments show that the forcing function generator fluid dynamics is significant with regard to the resulting unsteady aerodynamic gust response. Also demonstrated is the decreased correlation of the gust response data with linear theory predictions as the steady loading is increased.