Jiraporn Yojina, Waipot Ngamsaad, Narin Nuttavut, Darapond Triampo, Yongwimon Lenbury, Paisan Kanthang, Somchai Sriyab and Wannapong Triampo
The Journal of Mechanical Science and Technology, vol. 24, no. 10, pp.2025-2034, 2010

Abstract : In this work, mesoscopic modeling via a computational lattice Boltzmann method (LBM) is used to investigate the flow pattern phenomena and the physical properties of the flow field around one and two square obstacles inside a two-dimensional channel with a fixed blockage ratio, β =1 4, centered inside a 2D channel, for a range of Reynolds numbers (Re) from 1 to 300. The simulation results show that flow patterns can initially exhibit laminar flow at low Re and then make a transition to periodic, unsteady, and, finally, turbulent flow as the Re get higher. Streamlines and velocity profiles and a vortex shedding pattern are observed. The Strouhal numbers are calculated to characterize the shedding frequency and flow dynamics. The effect of the layouts or configurations of the obstacles are also investigated, and the possible connection between the mixing process and the appropriate design of a chemical mixing system is discussed.

Keyword : Flow pattern; Lattice Boltzmann method; Strouhal number; Von Karman vortex street