High precision manufacturing machines often require extremely tight tolerances in their end products. Hence vibrations induced by flow within internal components such as an orifice, can cause deviations in measurements and defects in production. These vibrations caused due to orifices are a result of large pressure drops generated during flow separation resulting in pressure waves that propagate within the system interacting with other components. In this article vibrations resulting from orifice flows are comprehensively studied through a series of experiments and numerical validation. The experimental and numerical study is performed to validate and analyse the pressure fluctuations of separated flows through a single holed orifice plate. The experiments performed involve pressure measurements with various orifice diameters at measurement points upstream and downstream of the orifice plate. The pressure signals obtained from the experiment are recorded and analysed with respect to their energy distribution. The study is further extended to analyse the effect of orifice diameters on pressure fluctuations, and in the process also observe and identify the phenomena of cavitation. The results obtained from this study forms a validation database for further numerical studies. To obtain a more detailed understanding of the flow and the underlying behaviour, a Large-Eddy Simulation (LES) of orifice flow is performed for a selected orifice. The LES results are validated using different databases involving previous studies and the results obtained from the experiments that have been performed during this study. The LES results are analysed in detail with regards to the spectral characteristics of velocity and pressure fluctuations using mathematical tools such as Fourier Analysis. The results provide an insight on the flow development, energy distribution and power spectrum distribution in the flow.
