PRESSURE AND VELOCITY FLUCTUATIONS IN STILLING BASINS
The internal flow of hydraulic jump is essentially an unsteady flow subjected to macro turbulent random fluctuations and it was not known enough. Then, for the fluctuating motion interpretation, the experimental research on the associated turbulence must be necessary. The authors developed in the past extensive laboratory research for the instantaneous pressure field determination by means of pressure transducers and new introductory experiments on velocity fluctuations by means of the ADV technique. The experimental study of the instantaneous pressure field was based on the knowledge of several statistical parameters of amplitudes and frequencies as functions of the Froude Number but for this paper only the root mean square of pressure and velocity amplitudes is considered.Following previous experimental conclusions, the tests were accomplished for incident Reynolds Number R1 up to 100,000 for incident Froude Numbers F1=3 and F1=5. Experimental data on turbulence intensity decay downstream the stilling basin obtained by means of direct velocity fluctuations and calculated through pressure fluctuations amplitudes measured below free or submerged hydraulic jumps stilling basins were used. A useful relationship between turbulence intensity and the pressure fluctuation coefficient Cp is proposed. As velocity fluctuations cannot be measured with precision in the upstream region of the hydraulic jump with the ADV equipment, these results obtained by extrapolation of the pressure fluctuations are presented.
hydraulic jump pressure fluctuations velocity fluctuations turbulence decay
Raúl A.Lopardo Martin Romagnoli
Instituto Nacional del Agua, Ezeiza, Argentina CONICET, CURIHAM-FCEIA, Universidad National de Rosario, Argentina
国际会议
第16届亚太地区国际水利学大会暨第3届水工水力学国际研讨会(16th IAHR-APD Congress and 3rd Symoposium of IAHR-ISHS)
南京
英文
2093-2098
2008-10-20（万方平台首次上网日期，不代表论文的发表时间）