Lead Investigator: Dr. Tam
Aircraft noise has now become a significant environmental issue as well as major competitive issue for businesses. The problem is aggravated by the rapid increase in the volume of air traffic. In Western Europe and part of the Far East, there is a great need and political pressure to enforce more stringent noise regulations around airports. From a business point of view, a company that manufactures quieter commercial aircrafts has an enormous advantage for sales at home and abroad. Since aircraft sales are an important item of US export, the ability to reduce aircraft noise would have an important impact on our national economy.
At take-off, a commercial jet engine produces its peak power, and propulsive noise from the jet stream of the engine is most dominant. During landing, the power is greatly reduced, and the noise from the fan of the engine becomes most dominant. Efforts to reduce jet and fan noise have been made for sometime. However, because the flow is turbulent and the fan blade and engine geometry are highly complicated, there is no good understanding of all important noise generation mechanisms. As a matter of fact, prediction methods for jet and fan noise are still largely semi-empirical. Significant noise reduction will not be possible until a better understanding of the physics of noise and a much improved prediction methodology become available.
Because of its complexity, jet engine noise forms a major application area of computational aeroacoustics that demands large-scale computation, . Work on computational aeroacoustics at the Florida State University began in the early nineties. Since then, great progress has been made in both the development of methodology and the application to aircraft and related noise problems. Other elements needed for computational solution of both jet and fan noise problems, such as numerical boundary conditions to be imposed at the outer boundaries of the computational domain, and artificial selective damping for eliminating spurious numerical waves, were also developed at FSU. These methods have been successfully applied to the study of the phenomena such as ``jet screech'', airframe tones and jet engine acoustic liner effects. Various NASA Research Centers, Boeing, and Pratt & Whitney are supporting the FSU group, regarded as a leading center in computational aeroacoustics.
Part of the objective of this proposal is to expand on the existing foundation in computational acoustics to form an even stronger group, and to encourage other FSU faculty members to become involved in this effort.