Testing two crackle criteria using modified jet noise waveforms.

Propagation of crackle-containing jet noise from high-performance engines

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...

On the Evolution of Crackle in Jet Noise from High-Performance Engines

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 pressure waveform time derivative is a better quantifier of the acoustic shocks believed to be responsible for its perception. This paper discusses two definitions of crackle, waveform asymmetry versus shock ...

Transformations of a crackling jet noise waveform and potential implications for quantifying the “crackle” percept

طراحی و ساخت نازل جت چند گانه با هدف کاهش صدای ناشی از تفنگ های بادپاش

Background and aims: Discharging compressed air through conventional single jet nozzles or open pipes is a common jet noise in industry. This study is aimed to reduce air blow gun jet noise by designing and fabrication of multiple jet nozzle as a substitute for conventional single jet nozzles.  Methods: One of the most common commercial air blow gun equipped with a conventional single j...

Validation of an automatic crackle (rale) counter.

Crackles are commonly used in clinical decision-making, and in certain diseases the number of crackles reflects the severity of the illness. Auditory crackle estimations are subjective; crackle counting from time amplitude plots of sound (called time-expanded waveforms) is more objective but is cumbersome. We devised a computer-based system to count crackles automatically. One hundred samples o...