Sharp-interface immersed boundary lattice Boltzmann method with reduced spurious-pressure oscillations for moving...

Area of Science:

• Computational Fluid Dynamics
• Numerical Methods

Background:

• Spurious pressure oscillations are a common issue in sharp-interface immersed boundary methods.
• These oscillations arise from violations of the geometric conservation law near moving boundaries.

Purpose of the Study:

• To develop a sharp-interface immersed boundary lattice Boltzmann method (IBLBM) that mitigates spurious pressure oscillations.
• To enhance the accuracy of simulations for moving boundary problems, particularly concerning pressure field fidelity.

Main Methods:

• A cut-cell-based approach, specifically the partially saturated computational cell method, is integrated with a sharp-interface IBLBM.
• The method modifies the ghost fluid approach to accommodate the cut-cell strategy, ensuring accurate boundary condition enforcement.
• Dirichlet and Neumann boundary conditions for both velocity and pressure are guaranteed.

Main Results:

• Simulations involving a circular cylinder undergoing various motions (at rest, translation, oscillation, neutral buoyancy) were performed.
• The proposed method effectively reduced spurious pressure oscillations compared to traditional sharp-interface IBLBM.
• Accurate simulation of moving boundary problems was demonstrated, with significant improvements in pressure field accuracy.

Conclusions:

• The developed cut-cell IBLBM offers a robust solution for reducing spurious pressure oscillations in moving boundary fluid dynamics.
• This method is particularly advantageous for applications where precise pressure field prediction is critical.
• The approach validates the importance of geometric conservation laws in immersed boundary methods.