DOI: 10.5593/sgem2017H/33/S12.033


Y. Kuznetsova, A. Pozdeev
Thursday 23 November 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgemviennagreen.org, SGEM2017 Vienna GREEN Conference Proceedings, ISBN 978-619-7408-27-0 / ISSN 1314-2704, 27 - 29 November, 2017, Vol. 17, Issue 33, 267-274 pp; DOI: 10.5593/sgem2017H/33/S12.033


Parameters of local scours in an unprotected part of the riverbed behind the hydrosystem end structures are determined by distribution of kinematic characteristics of the flow. The kinematic characteristics in cross-sections of a natural part of the riverbed depend on a number of factors, including the bottom roughness, flow depth and water surface slope. To solve the problem of calculating the velocity distribution over the cross-section of the drainage channel, we used Navier - Stokes equations for the uniform steady turbulent motion. We considered the application of Lorentz law to derive an equation of velocity profile in the flow depth. Based on a selected value of Karman constant, dimensionless longitudinal and transverse flow velocity profiles were obtained. We considered the possibility of applying U. Kelvin formula, which determines an induced velocity of a vortex ring, in order to calculate the kinematic characteristics of the flow. The calculation in MathCad showed the convergence of results of this approach with data of N.I. Makkaveev, who represented the flow structure as a series of whirlpools with vertical axes of rotation. We analyzed the velocity distribution according to A.M. Monin and found that the obtained parameters of dependences have a good convergence with the logarithmic profile according to model by Lorentz. We performed a comparative analysis of various types of the velocity distribution in the flow depth in MathCad. It was found that for all models of the velocity distribution, the largest discrepancy was observed in the bottom layer, where turbulent perturbations arise. We also studied the model by V.N. Goncharov. On the basis of the performed analysis, we selected the dependences which coincide with the experimental data the most. The results can be used to simulate the flow spreading and the local scours in the hydrosystem tailraces.

Keywords: local scour, hydrosystem, kinematic characteristics, velocity distribution, MathCad