Sensitivity of the Flow to the Inclination of a Single Submerged Groyne in a Curved Flume

Roughness Effect of Submerged Groyne Fields with Varying Length, Groyne Distance, and Groyne Types

“…The groyne width (w G ) was 6 cm and the projected length of the groyne (l P ) was 20 cm (1/3 of the flume width). The angle of inclination was chosen to 60 • against stream direction ( Figure 2) as several studies e.g., [13,18,26] recommend this angle for best protection of a bank. In experiments without groynes, the boundary conditions for uniform flow conditions at water depths hN = 5, 10, and 15 cm were determined by adjusting the flap gate and the discharge until the target water depth was constant along the flume.…”

“…A similar scouring effect due to the groyne shape was observed by Bressan and Papanicolaou [4] for stream barbs up to a certain level of submergence and by Kadota et al [8] for permeable submerged groynes. Using the gravel groyne model (Figure 1b) for investigating the effect of geometric groyne parameters [26] and of the position of a submerged groyne [27] on the velocity field in a curved laboratory channel, which finally resulted in recommendations for arranging a submerged groyne field for protecting the outer bank of a bend [2]. However, only one hydraulic boundary condition was adjusted in the latter experiments and thus, the effect of a submerged groyne field on the water level cannot be estimated, yet.…”

“…The groyne width (wG) was 6 cm and the projected length of the groyne (lP) was 20 cm (1/3 of the flume width). The angle of inclination was chosen to 60° against stream direction ( Figure 2) as several studies e.g., [13,18,26] recommend this angle for best protection of a bank. The aim of the work described in this paper is to investigate the hydraulic roughness of fields of submerged groynes and to assess the effect of model boundary conditions.…”