Experimental Investigation and Modeling of Aeration Efficiency at Labyrinth Weirs

Abstract

For maintaining healthy streams and rivers, a high concentration of oxygen is desired and hydraulic structures act as natural aerators where oxygen transfer occurs by creating turbulence in the water. Aeration studies of conventional weirs are carried out widely in the past but at the same time, labyrinth weirs, where the weir crest is cranked thereby enhancing their crest length, have got a little notice. The test records were obtained through 180 laboratory observations on nine physical models to estimate aeration efficiency (E20) at labyrinth weirs (LWs). The E20 increases with the number of key as well as drop height and it is found to be highest for rectangular shape in comparison of the triangular and trapezoidal LWs, however, E20 decreases with the increase of discharge. Further, this work unravels the novel idea and potential of the M5P model tree (M5P), support vector regression machine (SVM), and Random Forest (RF) methods for estimation of aeration efficiency (E20) at LWs. The results depicted that the RF model performs best in determining the E20 at LWs. The results of sensitivity analysis further illustrated that drop height is the parameter that affects the prediction of E20 at the LWs most.