This research was conducted to characterize and develop a deeper understanding of the hydraulic flow noise for a spool valve. Hydraulic noise was analyzed to study the interaction of the valve spool and the flow noise generation to isolate where in the spool articulation the most noise was generated. The goal was to correlate turbulent fluid flow in pressurized hydraulic circuits to different spool positions while isolating what factors were the main drivers of spool noise generation. The experiments were conducted on a valve controlled by a closed-circuit hydraulic system, using this system fluid-born noise could be isolated from other noisy mechanisms and a noise profile of each could be measured. It was found that internal spool geometry and flow channel open area played the largest role in valve noise generation for the valve. In the future, more valves could be tested to develop a robust profile library using the test methods developed.

Corsi-Rosenthal (CR) boxes efficiently and cost-effectively clean the air in an environment; however, the constant broadband noise they produce is a concern. Measuring sound power levels of CR boxes would provide a metric for noise comparisons, but traditional sound power level measurements are not readily adaptable for the average consumer. Measuring the sound power level in a free field over a reflecting plane is an accurate method but is complicated and expensive involving multiple microphones in an anechoic chamber (ANSI S12.54-1999). The Comparison Method is a simpler procedure that can be performed directly in the environment of interest but requires an expensive calibrated source (ANSI S12.57-2011). To allow for simple and inexpensive sound power measurements of CR boxes, we used ANSI S12.54-1999 to measure the sound power of a $30 hand vacuum (Black+Decker HNVC115JB06) to explore its potential as a DIY calibrated source for the Comparison Method. The reproducibility and uncertainty of this DIY method will be discussed. The DIY method has the potential to enable noise comparison of air cleaners or other devices for the average consumer.