Numerical analysis of blockage effects on the flow between parallel plates by using lattice Boltzmann method

Abstract

In this study the two-dimensional flow over a square cylinder placed in between parallel plates is simulated numerically by using the lattice Boltzmann method (LBM) at low Reynolds numbers. Both the plates are obstructed by solid rectangular blocks of variable length. The fluid was allowed to flow between the parallel plates for Reynolds number (Re) from 75 to 150, and blockage ratio (g*) from 1 to 3. The numerical investigation does not simply yield the predictable primary region of recirculating flow connected to the obstructions; it also shows supplementary regions of the flow downstream of the single cylinder placed in a computational domain. These supplementary separation zones were not already described in the research. The numerical analysis shows that the flow downstream of obstructions and the single cylinder remained two-dimensional for Re varied from 75 to 150. Results available in previous research are reported and compared with both of the available experimental and numerical results for code validation with a single cylinder. Furthermore, the effects of various Re and blockage ratio on the lift forces and drag coefficient is analyzed. Under these circumstances, good agreement between experimental and numerical results are obtained. The hydrodynamic forces of the cylinder are strongly influenced by the spacing ratios.