Author(s): R. A. Lopardo; R. E. Henning

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Keywords: No Keywords

Abstract: The present paper deals with pressure fluctuations measurements in a laboratory flume beneath free and stea dy hydraulic jumps downstream a conventional spillway chute, over horizontal bed, with incident Froude num- bers between 4,5 and 10. The authors describe the exper imental equi pment based on pressure transducers and magnetic recordings, and they discuss the influence of Length and diameter of the tube which connects the flow with the transducer. The authors aLso include in this paper a sensibility analysis of numerical parameters for the data adquisi- tion, as the total time of record, the time interval for digitalisation, the number of blocks for power spectra calculation and the number of data by block. New exper imental data about RMS pressure fluctuations amplitudes, show the influence of infLow condition on the instantaneous pressure field below hydraulic jumps. The paper includes exper imental results on positive and negative pressure ampli. tudes with different probabi lities of ocurrence, as a function ot hte position in the jump, the Strouhal (for peak frequency) and the skewnessof the probability density function. This research is completed with the measurements of pressure fluctuations correlations in the flow direc- tion which have interest for the calculations of instantaneous forces on the bed surface.

DOI:

Year: 1985