Lattice Boltzmann methodology for unconfined flows

TL;DR

This paper demonstrates the application of the lattice Boltzmann method to simulate unconfined flow over a circular cylinder, addressing boundary condition challenges and validating results against existing literature.

Contribution

It introduces a lattice Boltzmann approach tailored for unconfined flows, including boundary condition implementation and validation for flow over a cylinder.

Findings

Flow simulation results agree with existing literature.

Boundary conditions effectively model unconfined flow.

Drag and lift coefficients computed accurately.

Abstract

Numerical analysis of unconfined flow over an obstacle has always been challenging in computational fluid dynamics due to the truncation of the computational domain while replicating the real-life flows and the application of the boundary conditions. Confined flows studies have been well established and documented while unconfined flow studies are relatively challenging. Present work demonstrates the implementation of lattice Boltzmann method for unconfined flow over a circular cylinder for Re 100. The cylinder was placed at 10D upstream and 30D downstream and 10D from both the top and bottom walls. Different boundary conditions were implemented at the top and bottom walls to ensure unconfined flow. Drag and lift coefficients are also presented and were computed using the momentum exchange algorithm. Results are in complete agreement with the existing literature which demonstrate the capability of the solver.