Volume 20, Numéro 2, Pages 173-194

An Energy Perspective Of Composite Broad Crested Weir For Measuring Accurate Discharge

Authors : Kulkarni Ketaki . Hinge Ganesh .


This paper reports the computational fluid dynamics and experimental fluid dynamics studies conducted for the measurement of release by a composite broad-crested (CBC) weir. Studies conducted thus far depict that manufacturing composite weirs for precise discharge measurement is a demanding field. The performance of composite broad crested weirs as flow measuring devices depends on the weir width (b), height of the weir and upstream flow over the weir crest (h). Thus, a change in the geometry of the weir for a given flume will determine the flow characteristics, mainly the discharge coefficient (Cd), which changes according to the h/b ratio. At present, researchers have maintained an average range of Cd for various h/b ratios. This study is related to CFD investigations regarding hydraulic properties to determine optimized weir geometry. FLOW 3D deploys accuracy in free surface simulations where the model employs a renormalized group (RNG) approach with volume of fluid (VOF). To validate the CFD model, laboratory models were used. In this research, flow depth parameters on the weir crest and velocity distribution on a composite broad-crested weir were evaluated. The experimental observations were used to validate the 3-D CFD models, and then the geometry of the composite broad-crested weir was optimized to obtain a constant Cd. The results of both the performance of the CBC weir for precise measurement of a wide range of discharges are confirmed by numerical models and experimental observations by fairly maintaining a constant design input value of the discharge coefficient of 0.6. Compared to empirical methods, optimization of the weir geometry through CFD definitely yields the correct model prediction. Furthermore, additive manufacturing of this optimized model with poly lactic acid plastic material validated the weir performance with accurate estimations between theoretical, experimental, and CFD outputs. The applications of the proposed method from the energy aspect are highlighted.


Composite Broad Crested Weir ; Coefficient of Discharge ; Flow 3D ; 3D printer ; Energy