Cavitation Nuclei Population Dynamics in a Water Tunnel

The free stream nuclei number distributions in the Low Turbulence Water Tunnel at Caltech were measured using a Phase Doppler Anemometer. The changes in nuclei number distributions with water tunnel running time, with initial air content, with tunnel velocity varying from 2m/sec to 9m/sec and with water tunnel static tunnel pressures ranging from 40kPa to 110kPa were examined. Quite complex changes in nuclei number distributions were observed in the nuclei size range of interest from the point of view of cavitation, namely the range from 5 to 200[microns]. Order of magnitude changes were observed in the nuclei population