The possibility of jet-installation noise reduction has been experimentally demonstrated using a flat-plate fitted with flow permeable metal foam at the trailing-edge. Tests were conducted for single-stream cold subsonic jets round nozzle adjacent to wide range velocities (M=0.3?0.9) in an anechoic chamber. Thorough investigations far-field various polar angles carried out demonstrate regions r...

Jet noise is a common problem in minimum quantity lubrication (MQL) technology. This should be given great attention because of its serious impacts on the physical and mental health operators. In this study, micro-grooved nozzle proposed based reduction concept biological micro-grooves. The flow field acoustic characteristics an original were investigated numerically to help better understand m...

A Helmholtz resonator with a curved cavity is studied for reducing jet-installation noise in configuration comprised by subsonic jet and nearby flat plate. The face-sheet are designed the Guess method impedance verified through an experiment simulation of tube. Both single double degree-of-freedom liners, latter perforated septum inside cavity, studied. good agreement obtained curves from desig...

Noise generation in a subsonic round jet is studied by a simplified model, in which nonlinear interactions of spatially evolving instability modes lead to the radiation of sound. The spatial mode evolution is computed using linear parabolized stability equations. Nonlinear interactions are found on a mode-by-mode basis and the sound radiation characteristics are determined by solution of the Li...