齿形尾坎消力池消能紊动特性研究

AN EXPERIMENTAL STUDY OF THE TURBULENT FLOW IN THE STILLING BASIN WITH DENTATED SILLS

By using the Laser Doppler Velocimeter of polarization differentiation and Jsp-1 signal processor-counter, an experimental study of the turbulent flow characteristics downstream of the stilling basin with dentated sills (Rehbock Sills) was carried out. Comparative studies of that with the trapezoidal profile sills in the same hydraulic conditions were-made. Based on these results, the turbulence intensity, turbulent energy, density function of power spectral, frequency characteristics and the actual energy dissipation rate of the forced hydraulic, jump were analyzed. The vertical distribution, the longitudinal transformation and the decay pattern of these turbulence parameters were found to have good relations with Froude numbers. Moreover, it was found that the turbulent energy, and turbulence intensity of the flow with dentated sills were much less than that with trapezoidal sills in all sections. It is evident that, because of the dentation which divides, the flow, the dentated sills not only improve the velocity distribution, but also increase the intermittent zones between the secondary flow of the rollers and primary flow and make the turbulence energy decay faster. Hence, comparing with trapezoidal sills, the energy dissipation rate of dentated sills is larger and the scour holes are shallower, The mechanism of energy dissipation was explained.