Assessing Accuracy and Limitations in Calculating Drag Coefficients using the Lattice Boltzmann Method

The accuracy of drag coefficient calculations in Lattice Boltzmann simulations is investigated in this study through an examination of two distinct methodologies, the momentum reduction and momentum exchange methods. Simulations are conducted on circular and square geometries across a range of Reynolds numbers (۱۰, ۲۵, and ۵۹). The study further evaluates the impact of the distance from the obstacle on the computed drag coefficients by the momentum reduction method. The results reveal several key insights. Regardless of the Reynolds number, in the momentum reduction method, the drag coefficient decreases as the distance from the obstacle increases, emphasizing the need for a specific cross-section for precise extraction. The study also highlights the sensitivity of these methods to geometric factors, particularly for circular shapes at higher Reynolds numbers. Additionally, the momentum exchange method exhibits limitations for square geometries, which become more pronounced with increasing Reynolds numbers. This research offers valuable insights into the capabilities and limitations of the momentum reduction and momentum exchange methods in Lattice Boltzmann simulations. It underscores the significance of geometry, Reynolds number, and distance from the obstacle in the accurate calculation of drag coefficients. These findings contribute to the broader understanding of fluid dynamics simulations and provide practical guidance for researchers applying the Lattice Boltzmann method in diverse applications

Keywords:

LBM , Drag Coefficient , Momentum Reduction , Momentum Exchange