The Refracting Inlet: A New Concept for Aircraft Inlet Noise Suppression

Observations of wave refraction in flowfields containing large transverse velocity gradients have suggested a means by which refraction effects could be used to aid suppression of the noise propagating forward through aircraft gas turbine inlets. The first part of this paper describes an experiment using a schlieren apparatus to observe waves passing through inlet-type flowfields. The second part describes a test program using model inlets to examine the feasibility of the refracting inlet concept.