Modelling of Headloss due to Contraction in Hydraulic Systems

Prediction of headlosses in hydraulic systems is crucial in the design and monitoring of flows in physical models and prototypes. The geometric, fluid and flow properties of the contraction system were successfully determined. The system possessed two diameters; D1 and D2 with a ratio of 0.549, constant fluid properties and operated under laminar flow conditions. A dimensionless model was successfully derived using the Buckingham π theorem. The model parameters were determined through linear regression, with a slope k = 4.4783, intercept = 10.6103 and coefficient of determination of , confirming an excellent fit to the experimental data. The model's performance was evaluated using three statistical metrics: Relative Bias of 0.1843, Nash-Sutcliffe Efficiency of 0.9916, and Coefficient of Determination of 0.9937. These values confirm that the model is highly reliable for predicting headloss due to contraction under the tested conditions. The model was validated against existing literature and demonstrated comparable or superior performance to similar studies, confirming the dimensional analysis approach for contraction headloss prediction.