Numerical simulation of submerged flow bridge scour under dam-break flow using multi-phase SPH method.

Area of Science:

• Fluid Dynamics
• Geotechnical Engineering
• Computational Mechanics

Background:

• Bridge scour under extreme flow events like dam breaks poses significant risks.
• Accurate modeling of sediment-fluid interaction is crucial for predicting scour depth.
• Existing models may not fully capture the complexities of two-phase flow during dam-break induced scour.

Purpose of the Study:

• To develop and validate a coupled two-phase flow model for simulating submerged bridge scour under dam-break conditions.
• To investigate the influence of sediment-fluid interaction on scour depth.
• To analyze the impact of bridge deck geometry and flow parameters on scour evolution.

Main Methods:

• Employed the Smoothed Particle Hydrodynamics (SPH) method for simulating both sediment and fluid phases.
• Utilized a two-phase flow framework incorporating Newtonian and non-Newtonian fluid behaviors.
• Applied the Bingham-type Herschel-Bulkley-Papanastasiou constitutive model and Drucker-Prager yield criterion for sediment transport modeling.

Main Results:

• Successfully simulated sediment transport and predicted scour depth time histories under a submerged bridge deck.
• Quantified the influence of bridge deck geometry on the scour process.
• Demonstrated the impact of varying flow conditions on the resulting scour depth.

Conclusions:

• The developed SPH model provides a robust tool for analyzing bridge scour under complex dam-break flow scenarios.
• Sediment-fluid interaction significantly affects scour depth, necessitating coupled modeling approaches.
• Flow conditions and bridge geometry are critical factors influencing scour extent and must be considered in hydraulic design and risk assessment.