High Fidelity Simulation of Jet Noise Emissions from Rectangular Nozzles, Phase I

The proposed research is directly applicable to the US Navy's development of noise suppression technology for the F/A-18 E/F and JSF/F-35B programs. The F/A-18 E/F program office is currently engaged in development of retrofits for the General Electric F414-400 engine that entail the replacement of their nozzle seals with a new design of seals which feature chevron extensions at the trailing-edge. Comparable modifications are also being considered for the General Electric F404-400 engine for the F/A-18 C/D aircraft. Over the longer-term, the Navy's focus is shifting towards advanced suppressions concepts beyond chevrons, etc. for next-generation propulsion systems, where high-fidelity modeling will be crucial in supporting technology development. The proposed technology also has applicability in the automobile industry. Although significant resources are being spent in reducing noise from vortex shedding from side-view mirrors, the efforts are presently hindered by the absence of high fidelity predictive tools. The research proposed is of direct relevance to NASA's Fundamental Aeronautics Program, with its focus on development of supersonic commercial flight, while meeting current and future noise certification levels. In parallel with airframe design for supersonic flight, advanced propulsion concepts are also under development, with non-axisymmetric, rectangular nozzle designs that incorporate noise control concepts. The engines that will be used with these aircrafts require significant advances in noise control technology an undertaking for which high-fidelity LES modeling will prove crucial in providing insight into physics and also complementing laboratory tests. The validated model will support NASA's upcoming tests of scale-model single or dual rectangular nozzles, as well as nozzles with chevrons and bevels. The same high-aspect ratio rectangular nozzles are also of interest to the Subsonic Fixed Wing Project. More »