Fishway design not only takes into account the swimming abilities of target fishes, but also considers the hydrodynamic characteristics within the fishway. In this study, the flow fields of one vertical-slot fishway (i.e. VSF), five T-shape fishways (i.e. TSF-1~TSF-5) and two H-shape fishways (i.e. HSF-1 and HSF-2) are numerically simulated by solving the three-dimensional Reynolds-averaged Navier-Stokes equations and the K-Omega-SST turbulence model. The numerical results clearly indicate that the hydrodynamic properties of HSF-2 are overall superior to the remaining seven cases, in terms of the time-averaged flow pattern, the time-averaged velocity magnitude, the depth-mean timeaveraged velocity magnitude along the vertical-slot section, the volume percentages of the time-averaged velocity magnitude less than some critical values, and the distribution of the time-averaged turbulent kinetic energy. Therefore, HSF-2 is more friendly for fishes with relatively smaller sizes and weaker swimming capacities to transfer upstream. The novel HSF-2 is firstly proposed in this paper, and it is naturally designed during the process of improving the flow regime. Furthermore, the generalizability of the superiority of HSF-2 over VSF and the original T-shape fishway (i.e. TSF-1) has been exhibited with the aid of the numerical results of four operating conditions (i.e. Q = 400 L/s, 600 L/s, 800 L/s and 1000 L/s).
A good knowledge of hydraulic characteristics, particularly the retention curves, of the applied materials is necessary when studying the efficiency of a capillary barrier or numerically simulating flow of water in its layers. The main difficulties of their measurements originate in the fact that the coarse-grained soils of capillary barriers come from the state of residual moisture to the state of saturation within relatively small interval of pressure head. Hence, it is necessary to carry out the measurements in very fine steps of pressure head. Four materials of two capillary barriers are investigated in this paper. The tension apparatus according to Havlíček and Myslivec was used to measure their retention curves. Both branches of retention curves were measured in order to obtain data suitable for taking hysteresis into account. The method is described and the results are presented. Subsequently, the hydraulic characteristics of the materials are determined and their impact to the capillary barriers efficiency is investigated. The barriers were compared from the viewpoint of their efficiency using the measured data and tipping trough measurements made elsewhere. Explanation of the found differences was suggested and the effect of hysteresis was discussed., Dagmar Trpkošová and Jiří Mls., and Obsahuje bibliografii