Installing rough strip energy dissipators (R-SEDs) at the bottom of curved spillways can facilitate energy dissipation and flow stabilization. In this study, the effects of R-SEDs set at the bottom of a 60° bend in a spillway were examined. This spillway had a large width-to-depth ratio ( B / H > 5 ). Based on physical model tests, the distribution of hydraulic properties of the spillway under different runs was studied and analyzed. The results show that the R-SEDs effectively improved the flow pattern in the bend. The R-SEDs reduced the average dimensionless flow velocity by about 37.9% by increasing the roughness at the bottom of the bend. The energy dissipation rate of the R-SED decreased with an increase in discharge flow rate and ranged between 30% and 50%. These indicate that it is feasible to apply the R-SEDs to 60° bends of spillways with a large width-to-depth ratio at low-flow runs ( the   tested   discharge   flow   rate = 15   L / s ). These results will provide a theoretical basis for the R-SED design of similar curved spillways.

Rough-strip energy dissipators (R-SEDs) at the bottom of a spillway bend have energy dissipation and flow diversion effects on bend flow. In this paper, 12 groups of Plackett–Burman tests were conducted. Energy dissipation rate and coefficient of variation of superelevation were used as evaluation indices. Then, influencing factors (i.e., relative height, height ratio, spacing, angle and thickness of R-SEDs as well as centerline radius, width, angle and bottom slope of the bend) of energy dissipation and flow diversion effects of R-SEDs were analyzed using Minitab 21.1 in combination with the entropy weight method and the TOPSIS method. Relative height of R-SED and bend angle were significant factors affecting energy dissipation effects; height ratio of R-SED and centerline radius of the bend were significant factors affecting flow diversion effects; the weight of the coefficient of variation of superelevation (0.549) was larger than that of the energy dissipation rate (0.451), indicating that R-SEDs' flow diversion effects were larger than their energy dissipation effects; height ratio of R-SED, centerline radius of the bend and bend angle were significant factors affecting overall energy dissipation and flow diversion effects, and selected as the key factors for further steepest climbing tests and response surface design.

e rough-strips energy dissipator (R-SED) is applied to the bottom of the spillway bend and can play the role of energy dissipation and ow stabilization. In this study, based on 18 sets of orthogonal tests and the principle of dimensional analysis, a multifactor in uence model of R-SED's energy dissipation rate was proposed. A dimensionless factor k was introduced, which can re ect the comprehensive characteristics of the geometric dimensions of R-SEDs. e multifactor in uence model of the energy dissipation rate considered nine factors, including bend radius of curvature R c , bend width B, ow velocity of the bend inlet v, R-SED's average height h L , R-SED's arrangement angle θ, R-SED's arrangement spacing ∆L, uid density ρ, dynamic viscosity coe cient μ, and gravitational acceleration g. e residual sum of squares of the model (RSS) was 6.6% and the correlation coe cient R was 83.2% (>80%), indicating the universality and feasibility of the model.e independent variables of the multifactor model of the energy dissipation rate were ranked according to the Pearson value in descending order:. is indicates that R-SEDs' layout parameters showed larger e ects on the multifactor model of the energy dissipation rate, compared with the engineering layout parameters of the spillway. e maximum relative error between the predicted value of the multifactor model and the measured value of the validation group was 6.28%, indicating good agreement. In the orthogonal tests, scenario 5 had the highest energy dissipation rate (44.83%) with k = 0.023; scenario 16 had the largest k value (0.043), with an energy dissipation rate of 40.78%. e multifactor in uence model of R-SEDs' energy dissipation rate proposed in this paper was a semi-theoretical and semi-empirical calculation formula, which can provide reference and support for similar practical engineering designs.