Cross-Beam Dissipators in Abruptly Expanding Channels: Experimental Analysis of Flow Patterns

Experimental study of spatial hydraulic jump stabilization using lateral jet flow

“…Figure 7(b) compares the mean L j /y 1 values in the one-jet, two-jet, and non-jet modes of LJF with the Silvester (1964) and Hager (1992) equations (Equations ( 10) and ( 11), respectively). According to the observations in the hydraulic conditions leading to the S-jump, the main flow continues as a sinusoidal wave to the end of the flume (Hajialigol et al (2021) and Sharoonizadeh et al (2021) experiments also confirms this), and the first wavelength is selected as the S-jump length. It shows the possibility of erosion and scouring downstream of the basin with a length equal to Equations ( 10) and ( 11), and therefore, using the LJF system, especially with two jets, significantly affects spatial jump control.…”

“…They deduced that the combined performance of the separation rollers, the jump roller, and the channel bed converts vortical structures into smaller scales, resulting in energy loss of the hydraulic jump. Hajialigol et al (2021) examined a system of crossbeams to dissipate the flow's kinetic energy in the sudden expanding stilling basin. They showed that beam spacing and system slope are the most effective geometric parameters for the system's efficiency.…”

Experimental Analysis on the Use of Counterflow Jets as a System for the Stabilization of the Spatial Hydraulic Jump

“…Still, practical situations exist where the downstream tailwater depth is very low and the classical jump cannot be created, even with the use of dissipation elements. In similar conditions, channel expansion can be a suitable solution [17], which, however, is prone to the possible occurrence of spatial hydraulic jumps (i.e., S-jump), characterized by unstable and asymmetric flows for specific narrow ranges of tailwater levels, for which a slight variation in the boundary condition can result in strong modifications of the cross-sectional velocity distribution and local velocity maxima [18][19][20][21][22][23][24][25]. Previous studies have demonstrated that these undesirable phenomena may be prevented or limited by inserting in the stilling basin solid sills [20,26], roughness elements [27], or cross-beam devices [24,25].…”