Influence of Orifice Aspect Ratio on Formation and Noise Characteristics of a Cavitation Jet

This study was focused on the elucidation of a cavitating jet behavior issuing from a rectangular orifice with different aspect ratios and its noise characteristics to get useful design information for water hydraulic spool valves. Control rectangular orifice geometry, aspect ratio and opening area, changes with stroke of a spool. Previous studies by the authors show that the noise generated from a cavitating jet becomes smaller with a larger aspect ratio and smaller opening area. The aspect ratio and the area change simultaneously in the valve. Evaluation of the influence of these geometries individually is important for deep understanding. Visualization of the jet with a high-speed camera and noise measurement were conducted. Cavitation jet behavior strongly depends on the supplying and downstream pressure of the orifice. The trend of the characteristics of the noise is almost the same for different aspect ratios. The largest orifice shows the highest flow coefficient with the lowest noise.