An experimental investigation of a low aspect ratio rectangular nozzle's flow field was completed. Over, ideally, and under expanded operating conditions were presented for nozzle temperature ratios of between unity and three. The aim of this study was threefold, first to validate the newly constructed heated jet noise rig at the University of Cincinnati, second to provide data for future computational validation, and third to compile acoustic baselines for future noise reduction studies. Validation of the experimental results was achieved through comparison to jet noise theories and empirical relations, particularly the fine and large scale similarity spectrum, screech frequency predictions, and scaling of acoustic intensity with powers of the expansion factor β. Excellent comparisons were achieve with limited deficiencies identified, such as possible nonlinear propagation and/or rig noise contamination at high frequencies for elevated temperatures. It was found for the current experimental setup that screech was eliminated at highly elevated temperatures. This phenomena that is still currently debated and bears further investigation. Additionally, the noise source known as crackle was briefly investigated, and it was found that at elevated temperature and pressure ratios the measured acoustics met the criteria for a crackling jet.
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