Acoustic Measurements of Compressible Jet Flow from a Pipe Nozzle with Clover Cross-section

The experimental work is carried out on jet flow issuing from a pipe with clover cross section. A compressible jet facility is used to produce the jet. The settling chamber pressure is varied from 2 to 6 bar. The noise generated by the jet flow are captured inside the semi-anechoic test facility which provides a free field acoustic environment. A calibrated condenser microphone along with the signal conditioner and computer based data card are used to acquire sound signals. The captured sound signals are converted to Sound Pressure Level (SPL) using Matlab. Overall Sound Pressure Levels (OASPL) are calculated from the SPL. The results shows that sound pressure levels increases as the pressure increases. The spectrum plots reveals that the noise capture are of broad band in nature and no tonal noises are present. The absence of tone even at higher pressures may be due to enhanced mixing offered by the clover geometry or the tones may be propagation in directions away from capturing mic locations.