Lattice Boltzmann simulation of free surface flow impact on a structure

Area of Science:

• Fluid dynamics
• Computational physics
• Marine engineering

Background:

• Marine structures face continuous impact loads from breaking waves.
• Accurate simulation of liquid impact is crucial for structural design and safety.
• Existing methods require validation against experimental data.

Purpose of the Study:

• To compare and analyze impact load estimates from free surface lattice Boltzmann (LB) simulations with experimental measurements.
• To evaluate the performance of two different LB models (BGK-F1 and MRT-F2) in predicting liquid impact loads.
• To validate LB simulations for various liquid impact scenarios relevant to marine structures.

Main Methods:

• Two-dimensional (2D) and three-dimensional (3D) simulations of dam break impact using the lattice Boltzmann method.
• Implementation of two LB models: Bhatnagar-Gross-Krook (BGK)-F1 and Multiple Relaxation Time (MRT)-F2.
• Comparison of simulation results (pressure, waterfront evolution, free surface profile) with experimental data from literature.

Main Results:

• The BGK-F1 model yielded pressure estimates closer to experimental measurements compared to the MRT-F2 model.
• Both LB models showed similar predictions for waterfront evolution and free surface profiles.
• 3D simulations using BGK-F1 for impacts on a wall, obstacle, and tower showed good agreement with experimental load estimates.

Conclusions:

• The BGK-F1 lattice Boltzmann model is a reliable tool for estimating liquid impact loads on marine structures.
• LB simulations, particularly with the BGK-F1 model, can accurately predict forces experienced by structures under wave action.
• This validates the use of LB simulations for analyzing complex fluid-structure interactions in marine environments.