جستجوی مقالات مرتبط با کلیدواژه « صفحات مشبک » در نشریات گروه « عمران »

The aim of the current study, investigate the energy dissipation of the use of the vertical screen with two porosity ratios downstream of the inclined drop with three different angles, two heights of the drop, and the range of 200-700 l/min with an analysis of 140 laboratory models. The results revealed that the use of screens caused by an increase of at least 407% and a maximum of 903% of total relative energy dissipation efficiency to the plain inclined drop. The equations were presented to estimate the relative energy dissipation due to the use of a vertical screen downstream of the inclined drop with acceptable assessment criteria. Also, the contribution of each of the energy dissipation systems was presented. Then, intelligent models, Artificial neural network (ANN), and adaptive neuro-fuzzy inference system (ANFIS) were compared to estimate the relative energy dissipation using three parameters θ, P, and yc/∆z using evaluation criteria. The values of R2 and RMSE for the ANFIS model, were 0.996 and 0.006, respectively, and for the ANN model were 0.992 and 0.008 respectively, which revealed the higher accuracy of the ANFIS model in the estimation of the relative energy dissipation than the ANN.

In the present study, the effect of vertical drop, gradually expanding and vertical screens are investigated to increase the efficiency of the energy dissipation of the flow. The experiments were carried out in a horizontal laboratory flume with a rectangular cross section, two vertical drop heights, and the wall expanding ratios of 0.5 to 1, the porosity ratio of the screens of 40% and 50%, and The range of Froude number of 0.86-0.92. The results showed that the use of screens and expansion of the walls would increase energy dissipation and decrease the pool depth and the downstream depth. The application of expanding wall, screen and the effect of simultaneous use of screens and expanding walls increases the efficiency of energy dissipation by 25, 44 and 48 percent, respectively. The porosity ratio of the screen is not much efficient in energy dissipation, but it reduces the pool depth and increases the downstream depth. In the same hydraulic conditions, energy dissipation is increased and the depth of the pool decreases by increasing the height of the drops due to the increased jet severity over the drop striking the downstream bed. By increasing the discharge, the hydraulic jump formed in the upstream of the screens with a porosity ratio of 40% is submerged and moves upwards. However, in screens 50% of the jump is free and moves downward.