Axisymmetric cavities play a vital role in aerospace, pipeline, and several other industries. Compressible flows through cavities exhibit high amplitude self-sustained oscillations leading to dynamic acoustic loading. In order to effectively attenuate the cavity associated tones and noise, the cavity noise generation mechanism needs to be understood. Hence the present work aims to understand the pipe-cavity noise generation mechanism and the effects of upstream cavity hydrodynamic fluctuations on the downstream jet flow and its far-field acoustics. Hydrodynamic fluctuations are measured in the cavity while simultaneously measuring the far-field noise. Theoretical predictions and finite element analyses are carried out to study the cavity resonance frequency and corresponding mode shapes. The experimentally measured resonance frequency is close to the first tangential mode rather than higher modes. Scalogram and higher-order spectral analysis is implemented to unravel the mode switching and nonlinear interactions. It is also noted that the mode switching from pure tangential mode to combined mode is observed for higher depth cavities. Schlieren imaging method, POD, DMD and FFT analyses are implemented to unravel the effect of the upstream cavity on jet flow structure and to provide a link to the far-field acoustics. Linear and higher-order spectral analyses are implemented on the unsteady cavity pressure to comprehend the nature of the cavity acoustics and nonlinear interactions of different acoustic modes of the pipe-cavity system. The spatial structures of nonlinear modes and screech cases are obtained. Further, an experimental study is carried out with different inlet pipe lengths to show the effects on pipe-cavity jet noise. A thicker shear layer impinging upon the trailing edge of the cavity leads to suppression of instabilities compared to a thinner one. An increase in upstream pipe length leads to a decrease in overall sound pressure levels and acoustic power of the jet noise. Lastly, the passive control method of cavity noise using protrusion at various locations in the cavity is presented. The experiments are carried out for protrusion with different locations and varying lengths of the protrusion. The device aims to alleviate the feedback mechanism and the recirculation flow in the cavity system. The protrusion at the trailing edge effectively attenuates the cavity noise at both cavity pressure fluctuations and far-field acoustics. Besides helping gain a deeper understanding of the flow and acoustic physics, the results of the present work may help in designing pipe-cavity systems for various flow conditions and noise considerations.