An Analysis of the Inlet Plane Aerodynamics of an Oscillating Subsonic Cascade: An Evaluation of Experimental Data.
Abstract
An analysis has been performed on unsteady pressure data measured in the leading edge region of a subsonic cascade oscillating in pitch. The objectives of the investigation were to determine the sensitivity of the freestream velocity disturbance at the inlet plane to variations in interblade phase angle, to compare the behavior of the freestream velocity disturbance as a function of interblade phase angle with that of both the inlet area oscillation and the measured moment response of the cascade, and to determine the influence of the gap-to-chord ratio on the blade loading near the leading edge. In this study, it was found that the behavior of the unsteady freestream flow entering an oscillating subsonic cascade is strongly influenced by the interblade phase angle. A more important finding was that the primary trends in the freestream disturbance match those of both the inlet area oscillation and the moment response of the cascade. Because of this correlation, a hypothesis is presented that describes how the interaction between the inlet area oscillation and the freestream flow might be relevant to the behavior of the cascade moment response and thus to the stability of the cascade motion. Analytical predictions based on this hypothesis are in qualitative agreement with the measured trends. The effect of gap-to-chord ratio on the unsteady blade loading was studied and found to be substantial in two ways: it alters the degree of influence of leading edge dynamic stall on the chordwise load distribution, and it alters the degree of influence of the interblade phase angle on the amplitude of the load response. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 27, 1981
- Accession Number
- ADA096077
Entities
People
- Arthur O. St. Hilaire
Organizations
- United Technologies Corporation