冰盖对层流垂线流速分布的影响研究.

The slow flow under the ice-cover can be approximated to laminar flow between two parallel inclined plates, which provides a basis for the theoretical solution of the vertical flow velocity distribution under the ice-cover. In this paper, the vertical velocity distributions of laminar flow in open channel and that under ice-cover were studied comparatively by means of theoretical analysis. It was shown that the vertical velocity distribution of laminar flow in open channel and that under ice-cover could be expressed in a unified parabolic form, however, the vertical velocity distribution of the laminar flow in open channel could be completely determined, but which of the laminar flow under ice-cover varied with the longitudinal pressure gradient. At the same time, flow velocity in vertical line, the maximum value of vertical velocity, the average value of vertical velocity, the unit discharge and the maximum velocity gradient of laminar flow under ice-cover were all less than the corresponding values of the laminar flow in the open channel. The results show that the ice-cover affects the discharge by affecting the vertical velocity distribution and both the discharge and the water transport rate are greatly reduced. In order to ensure the adequate water supply of water conveyance channels in winter, the adverse effects of ice-cover should be avoided. [ABSTRACT FROM AUTHOR]