"The acoustic signature generated by test articles in high speed wind tunnel tests is difficult to measure due to the high level of background noise created by the wind tunnel flow. A unique research program using microphone arrays is proposed to addressthis issue. The program combines experimental… More

The exhaust flow from a turbofan engine operating at typical cruise conditions generates noise as turbulent flow interacts with the basic shock cell pattern. This can be a significant source of noise within the aircraft cabin. The proposed innovation is a new method for testing the acoustics of… More

The exhaust flow from a turbofan engine operating at typical cruise conditions generates noise as turbulent flow interacts with the basic shock cell pattern. This can be a significant source of noise within the aircraft cabin. The proposed innovation is a new method for testing the acoustics of… More

Optical measurements including laser velocimetry (LV), particle image velocimetry (PIV), and other similar techniques are becoming a more important part of aerodynamic testing. However their implementation into large production wind tunnels is severely hindered by difficulties with flow seeding.… More

With improvements in high performance military jet aircraft engines and the increase in complexity of the exhaust systems the noise produced has become problematic. Reducing these noise levels, while maintaining overall system performance, has become the driving issue in new nozzle designs. This… More

With improvements in high performance military jet aircraft engines and the increase in complexity of the exhaust systems the noise produced has become problematic. Reducing these noise levels, while maintaining overall system performance, has become the driving issue in new nozzle designs. This… More

Recent advancements in open rotor engine concepts warrant continued research, however the cost of wind tunnel tests is not insignificant. Because the jet noise of an open rotor engine, or even that of a geared fan, is very low in relation to the fan noise, it is evident that fan noise reduction… More

A microphone array system for studying the near field hydrodynamic region adjacent to the supersonic exhaust plume of a tactical aircraft engine in a ground test fixture at approximately 20 feet above the ground. It will consist of approximately 160 microphones aimed radially inward at the edge of… More

ABSTRACT: The traditional approach to establishing test cell correlation factors is expensive and time consuming requiring multiple engine runs to establish a parametric database for comparison. While a complete alternative to this process, is unlikely, it is clear that there are procedures and… More