Modeling a decrease in hydraulic losses during turbulent flow in a U-bend channel with a circular cavern with a large opening angle

The Reynolds equations for incompressible viscous fluid, closed using the Menter shear-stress-transfer model modified with allowance for the curvature of flow lines, have been numerically solved using multiblock computational technologies. The obtained solution has been used to calculate the turbulent flow in a U-bend channel containing a circular cavern with a variable opening angle. Predictions based on the results of numerical simulations agree well with the experimental data of Savelsberg and Castro at moderate cavern opening angles. It is established that hydraulic losses in a U-bend channel with completely open cavern are significantly (by $\sim$ 25%) decreased as compared to those in a smooth channel at $\mathrm{Re} = 10^5$.