Session

Session 5 2022

Start Date

10-27-2022 12:00 AM

Abstract

A Piano key weir (PK weir) is a non-rectilinear spillway commonly used to augment the discharge capacity at the dams and diversion structures. Installation of such hydraulic structures may alter the flow characteristics, sediments transport and sedimentation in the river channels. The present study deals with an experimental investigation of three dimensional velocities near the two different laboratory models of PK weir having noses with an outlet overhangs. The purpose of this study is to observe the flow field in the vicinity of a one-cycle and two-cycle PK weir to understand the flow behavior of the weir that may be useful for sediment movement over weir. The velocity profile was measured at various grid points for both models considering unit discharges of 48.5×10-3 m2/s and 49×10-3 m2/s. The velocity fields near both inlet and outlet keys were examined and it was found that there is a considerable increase in the vertical (y-component) and lateral (z-component) velocities. It was observed that the rise in the mean velocity along longitudinal, vertical and lateral direction was more for two cycle PK weir due to increased crest length. For both discharge, the maximum velocity was observed near the inlet key. Computational Fluid Dynamics (CFD) simulations were also used to understand the flow configuration over the PK weir. It was seen that the magnitude of velocity increased due to vertical contraction near the weir and the flow velocity is very high immediately downstream of PK weir.

Share

COinS
 
Oct 27th, 12:00 AM

Experimental Study on Three-Dimensional Velocity Near Piano Key Weirs

A Piano key weir (PK weir) is a non-rectilinear spillway commonly used to augment the discharge capacity at the dams and diversion structures. Installation of such hydraulic structures may alter the flow characteristics, sediments transport and sedimentation in the river channels. The present study deals with an experimental investigation of three dimensional velocities near the two different laboratory models of PK weir having noses with an outlet overhangs. The purpose of this study is to observe the flow field in the vicinity of a one-cycle and two-cycle PK weir to understand the flow behavior of the weir that may be useful for sediment movement over weir. The velocity profile was measured at various grid points for both models considering unit discharges of 48.5×10-3 m2/s and 49×10-3 m2/s. The velocity fields near both inlet and outlet keys were examined and it was found that there is a considerable increase in the vertical (y-component) and lateral (z-component) velocities. It was observed that the rise in the mean velocity along longitudinal, vertical and lateral direction was more for two cycle PK weir due to increased crest length. For both discharge, the maximum velocity was observed near the inlet key. Computational Fluid Dynamics (CFD) simulations were also used to understand the flow configuration over the PK weir. It was seen that the magnitude of velocity increased due to vertical contraction near the weir and the flow velocity is very high immediately downstream of PK weir.