Studying subcritical opposing channel flows

This study investigates the hydraulics of opposing open channel flow (OCF) by using computational fluid dynamics software–Fluent. The model is validated with the velocity fields, flow separation zone, and water surface elevation obtained from experimental study available in the literature. 3D flow structures and turbulence characteristics of the validation problem are also discussed. In total, 81 cases of opposing flows are studied varying the discharge ratio, Froude number at the exit, the width ratio, and the aspect ratio of the exit channel. Simulated results are used to develop empirical equations for contraction coefficient, flow depth ratio, and minimum water depth in the contracted section of the OCF. The energy loss coefficient is computed from the simulated results. Contraction coefficient, flow depth ratio, and energy loss coefficient of OCF and corresponding values of right-angled channel junction flows are compared.