Turbulent intensity and scales of turbulence after hydraulic jump in rectangular channel. Experimental research was undertaken to investigate the changes in spatial turbulence intensity and scales of turbulent eddies (macroeddies) in a rectangular channel and the influence of the hydraulic jump on vertical, lateral and streamwise distributions of relative turbulence intensity and scales of turbulent eddies. The results of three tests for different discharges are presented. An intensive turbulent mixing that arises as a result of a hydraulic jump has a significant effect on instantaneous velocity, turbulent intensities and sizes of eddies, as well as their vertical and longitudinal distributions. In the analysed case the most noticeable changes appeared up to 0.5 m downstream the hydraulic jump. In the vertical dimension such an effect was especially seen near the surface. The smallest streamwise sizes of macroeddies were present near the surface, maximum at the depth of z/h = 0.6 and from that point sizes were decreasing towards the bottom. The intensive turbulent mixing within the hydraulic jump generates macroeddies of small sizes

Observed changes in hydrological conditions indicate the need for economical use of water. This pertains to water management on a national scale, river basins and drainage systems. The outflow of water can be extensively regulated after various forms of retention in the catchment. The water level regulators presented herein enable the damming of water in drainage networks and the adjacent ground. Their advantages include their simple structure and operation principles and also the ability to adapt to currently existing devices in sub-irrigation systems. Laboratory tests were conducted to determine the hydraulic characteristics and operating conditions of three innovative regulator solutions. They focused on changing water damming heights by the closure of successively placed beams in order to obtain the required water level in the given hydrometeorological conditions. The structures of the regulators were made of plastics and rectilinear fillings for securing S-type excavations and elements of sheet piling with a developed shape in the plan of U and Z types, offering advantages compared to traditional materials (with respect to installation, operation and durability). All tested regulators were characterized by the effective flow Q_e, caused by water leaks due to the lack of tightness of the regulator elements. The regulator with rectilinear beams of S-type closures offered the highest effective flow, which was 4 ÷ 5 times higher than in other regulators. U- and Z-type regulators were better at facilitating the regulation of the water table and the flow than the S rectilinear regulator. This led to both: the greater tightness of connections and the use of an overflow with a developed crest in the plan. The U and Z controllers had the highest hydraulic efficiency, expressed as the flow increase coefficient, at overflow layer heights of up to 5.0 cm. For tested fillings larger than 5.0 cm, U-type beams with a cylindrical corner shape had a lower flow increase coefficient (k_q = 1.25) than Z-type beams with an angular corner shape, for which k_q ∈ .

The study presents experimental investigations of spatial turbulence intensity and scales of turbulent eddies (macroeddies) in a rectangular channel and the impact of the hydraulic jump on their vertical and streamwise distributions over a flat and scoured bed. The results of four tests and two different discharge rates are presented. Intensive mixing caused by the hydraulic jump has an impact on the instantaneous velocity, turbulence intensity and sizes of macroeddies, as well as their vertical and longitudinal distributions along the channel. The largest differences in turbulence characteristics were reported directly after the hydraulic jump, above the eroded bed. The interaction between the stream of the increased turbulence and the bed is a direct cause of formation of scour downstream water structures, which has a great effect on overall flow characteristics. The scour hole that arose downstream the jump moderated, in a small degree, the turbulence intensity at its end. Just next to the hydraulic jump only the small longitudinal relative sizes of macroeddies were present, while at the end of the analyzed reach, downstream of the scour, the relative scale reached around 1.5 depth of the stream.