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...

Jet engines need to be certified before going into service, i. e., any dangerous vibration has to be detected. Therefore the eigenmodes, displayed as curves in Campbell diagrams, need to be identified first. At the moment this is done manually by engineers. In this paper we introduce a way of automatically detecting eigenmodes in Campbell diagrams by introducing an extension of Hough transform.

A new method for reducing large-scale mixing noise from dual-stream jets is presented. The principle is reduction of the convective Mach number of turbulent eddies that produce intense downward sound radiation. In a jet representing the coaxial exhaust of a turbofan engine, this is achieved by tilting downward, by a few degrees, the bypass (secondary) plume relative to the core (primary) plume....

Our world still greatly relies on the combustion process to convert fuel into power and heat for purposes such as gas turbines, internal (IC) engines, jet rockets, boilers, furnaces [...]

Jet engines are nonlinear dynamical systems for which an exact mathematical model cannot be used for estimator design, because it is either not available or so complex that it does not fit the necessary assumptions. Thus, classical analytical tools for studying standard system properties like observability, which is very important in estimator design, cannot be directly applied. Generally, for ...

Introduction In order to cancel Gedeon streaming in traveling wave thermoacoustic devices, a jet pump can be used [2, 3]. Due to its asymmetric shape an asymmetry in the minor losses during each acoustic cycle occurs that yields a time-averaged pressure drop across the jet pump. By balancing the time-averaged pressure drop across the jet pump with that which exists across the regenerator of a t...

Application of Compressed Natural Gas (CNG) in diesel engines has always been important, especially in the field of automotive engineering. This is due to easy accessibility, better mixing quality and good combustion characteristics of the CNG fuel. In this study the application of CNG fuel along with diesel oil in a heavy duty direct-injection automotive diesel engine is experimentally investi...