Abstract
The relation of time averaged conjugate depth and the characteristic of the length of hydraulic jump have been almost clarified. The time averaged pressure distributions around the end sill are also measured by several researchers. On the other hand, bed materials near the roller of hydraulic jump are sometimes picked up by the pressure fluctuations, so that it is quite important to investigate characteristics of the pressure fluctuations in and around the hydraulic jump. In this study, the fluctuations of bed pressure in and around roller and also instantaneous flow depth are measured with the pressure gauges and supersonic wave gauges, respectively. It was found that oscillations of roller influences on the instantaneous flow depth and bed pressure and also that the instantaneous bed pressure concerns with the instantaneous free surface fluctuations.
