Military jet aircraft are exposing both ground maintenance personnel and the community to high levels of noise. The US Department of Defense is funding research to develop advanced modeling tools for noise reduction techniques and community noise exposure. For these tools to achieve their full potential, innovative measurement and analysis methods are necessary to characterize the jet noise sou...

This paper presents a computational investigation of a tangential slot blowing conccpt for generating lateral control forces on an aircraft fuselage forcbody. The effects of varying both the jet width and jet exit velocity for a fixed location slot are analyzed. This work is aimcd at aiding rrscarchcrs in designing future experimental and compm tational models of tangential slot blowing. The pr...

Published near-field analyses of full-scale jet noise are limited, and the application of observed laboratory-scale phenomena to full-scale jets is not well understood. To obtain a greater understanding of the connection between radiated noise and source characteristics in full-scale, heated, supersonic jets produced by military aircraft, extensive acoustical measurements were made in the geome...

Because of the high noise levels radiated by military jet aircraft, it has been hypothesized that nonlinearity influences the propagation of the noise. A numerical model, which accounts for second-order cumulative nonlinearity, atmospheric absorption and dispersion, and geometrical spreading, has been developed to propagate jet noise waveforms. Numerical propagation of recorded waveforms from r...

The ingestion of volcanic ash by jet engines is widely recognized as a potentially fatal hazard for aircraft operation. The high temperatures (1,200-2,000 °C) typical of jet engines exacerbate the impact of ash by provoking its melting and sticking to turbine parts. Estimation of this potential hazard is complicated by the fact that chemical composition, which affects the temperature at which v...

It is desirable to isolate independent noise sources in jets for targeted noise reduction methodologies. The application of traditional partial field decomposition (PFD) techniques to jet noise fields is useful for estimating the number of incoherent (equivalent) noise sources within a jet and for implementing near-field acoustical holography, but it does not generally provide physically meanin...

Crackle, the impulsive quality sometimes present in supersonic jet noise, has traditionally been defined in terms of the pressure waveform skewness. However, recent work has shown that the pressurewaveform time derivative is a better quantifier of the acoustic shocks believed to be responsible for crackle perception. This paper discusses two definitions of crackle: waveform asymmetry versus sho...

Insight into the knowledge of Automatic Flight Control Systems gives an understanding of the basic problem of controlling the aircraft’s flight, and enhances its ability to assess the solutions to the problems which are generally proposed. There are a number of flight missions which require that an aircraft be made to follow, with great precision, some specially defined path. Whenever a convent...

Bio-jet fuel has attracted a lot of interest in recent years and has become a focus for aircraft and engine manufacturers, oil companies, governments and researchers. Given the global concern about environmental issues and the instability of oil market, bio-jet fuel has been identified as a promising way to reduce the greenhouse gas emissions from the aviation industry, while also promoting ene...

Recent concerns of the growing impact of aviation on climate change has prompted the emergence of a field referred to as Sustainable or “Green” Aviation dedicated to mitigating the harmful impact of aviation related CO2 emissions and noise pollution on the environment. In the current paper, a unique “green” business jet aircraft called the TransAtlantic was designed (using analytical formulatio...