Author(s): T. I. Eldho; Gaurav Misuriya

Linked Author(s): Eldho T.I.

Keywords: Pressure flow; Hydrodynamics; Contraction length; Local scour; PIV

Abstract: Recently, the frequency of high flood events in many parts of the world has been increased due to climate change impacts. In many locations, submergence of bridge deck is a very common phenomenon which is observed during the high flood events. A submerged deck changes the flow condition from open flow to pressurized flow under the deck. The flow hydrodynamics under pressure flow conditions can significantly differ from open flow conditions. As the present status of bridge design is based on the open flow condition, it became essential to investigate the hydrodynamic and scour characteristics under the pressure flow conditions which can be helpful in revising our design standards for the bridge considering the pressure flow during a high flood event. This study experimentally examined the effect of contraction length (deck length) on flow patterns, vortex strength, and turbulent kinetic energy under pressurized flow conditions. Velocity measurements were conducted using Particle Image Velocimetry (PIV) to capture detailed flow structures. Furthermore, the frequency of intermittent vortices was analysed for a plane rigid bed to better understand the conditions that initiate the scour. The equilibrium scour depth was also investigated under pressurized flow conditions. The results indicated that as the contraction length increases, both vortex strength and turbulent kinetic energy decrease. This reduction in flow strength for a rigid bed leads to a corresponding decrease in equilibrium scour depth on a sand bed with an increase in contraction length.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P2005-cd

Year: 2025