Cavitation in high suction tensiometers: Effect of temperature, time of use, and stone drying

Abstract

In high suction tensiometers, cavitation occurs when the tension in the water inside the device exceeds a certain threshold. The threshold corresponds to the formation of air bubbles either by air entry into or formation within the porous stone or reservoir. The standard procedure to inhibit air bubble formation in the device is to flood under vacuum and apply water at high pressure to force any remaining air bubbles to dissolve. A series of factors are, however, likely to influence the cavitation behaviour of high suction tensiometers. This paper demonstrates that: (1) there are no precursory phenomena leading to cavitation, (2) higher pressures are not essential for saturation, (3) cooler temperatures and tensiometer usage decrease the pore water pressure at cavitation, and (4) high suction tensiometers record increasing pressures when plunged dry in free water. The findings provide useful guidance to researchers using these devices for suction measurement. © 2012 IEEE.