Session

Session 10 2022

Start Date

10-27-2022 12:00 AM

Abstract

Many high dams on the upper Himalayan rivers which have very steep bed slopes are constructed with orifice type of Spillways with low level sluices for flood disposal and flushing of sediments. To assess the performance of spillway physica  model studies were conducted on a 1:50 scale 2-D sectional model. Physical model studies can have a wide range of outcomes depending on the purposes of the model study, although many physical models frequently analyse properties such as velocity patterns, discharge rating curves, water surface profiles, and pressures. The physical measurements highlighted that the spillway is subjected to negative pressures. To overcome this, different spillway profile options were verified using numerical methods.  For this, a commercially available computational fluid dynamics (CFD) program FLOW 3D was used which solves the Reynolds-averaged Navier-Stokes equations along with RNG turbulence closure model. Numerical modelling is quite beneficial when used by the designer in combination with the physical modelling. Numerical modelling enables designers to evaluate several possibilities until they find the hydraulically optimal solution, which can then be evaluated on a physical model, reducing the expense of physical model studies. In order to validate the numerical modelling results, the measured data from physical model studies for the original profile of spillway is used.  Discharge passing through spillways, water surface profiles and pressures were used to compare the results of the physical model and the numerical model. When it was seen that there is reasonably good agreement between the physical and numerical model results, then all other alternatives were analyzed numerically and an alternative having a hydraulically optimal solution was selected to study on the physical model.

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Oct 27th, 12:00 AM

Flow Over Orifice Spillway: Physical and Numerical Study for Spillway Profile Design of Hydroelectric Project

Many high dams on the upper Himalayan rivers which have very steep bed slopes are constructed with orifice type of Spillways with low level sluices for flood disposal and flushing of sediments. To assess the performance of spillway physica  model studies were conducted on a 1:50 scale 2-D sectional model. Physical model studies can have a wide range of outcomes depending on the purposes of the model study, although many physical models frequently analyse properties such as velocity patterns, discharge rating curves, water surface profiles, and pressures. The physical measurements highlighted that the spillway is subjected to negative pressures. To overcome this, different spillway profile options were verified using numerical methods.  For this, a commercially available computational fluid dynamics (CFD) program FLOW 3D was used which solves the Reynolds-averaged Navier-Stokes equations along with RNG turbulence closure model. Numerical modelling is quite beneficial when used by the designer in combination with the physical modelling. Numerical modelling enables designers to evaluate several possibilities until they find the hydraulically optimal solution, which can then be evaluated on a physical model, reducing the expense of physical model studies. In order to validate the numerical modelling results, the measured data from physical model studies for the original profile of spillway is used.  Discharge passing through spillways, water surface profiles and pressures were used to compare the results of the physical model and the numerical model. When it was seen that there is reasonably good agreement between the physical and numerical model results, then all other alternatives were analyzed numerically and an alternative having a hydraulically optimal solution was selected to study on the physical model.