Hydrodynamic Analysis of Special Shaped Submerged Panels in Curved Channels Using Three-Dimensional Numerical Modelling

This paper analyses the water flow in curved channels, which may present particular hydrodynamic patterns such as streamline alteration, cross-wave formation, recirculation zones and possible contour flow separations, all of which require detailed hydrodynamic analysis. The analysis focuses on a case study of a hydroelectric power plant intake with a side grate, which includes a curved (small-radius) gravel-removing channel connecting the intake works to two desanding chambers. This design results in an unequal distribution of flow to the desanding chambers, causing neither chamber to function properly, and a recirculation zone upstream of the left desanding chamber. The methodology uses three-dimensional numerical modelling in OpenFOAM, based on prototype data. The model was calibrated with a flow rate of 8,8 m³/s. Subsequently, the transit of the design flow of 13 m³/s was simulated and an uneven flow distribution in the desanding chambers was verified. To address this problem, and considering the higher-velocity streamlines, two groups of alternatives were considered: the first consisted of placing two panels of different special shapes (straight, broken, and curved) in the desilting chamber; the second examined the flow behavior with an increased number of panels and alteration aspect ratio. For the first group, the scenarios tested did not modify the flow distribution in the sand removal chambers; however, the panels locally changed the hydrodynamic conditions and successfully altered the recirculation zone location. The scenarios in the second group yielded the best operational results regarding flow distribution.