A numerical study on resistance characteristics of flow around two cylinders

Lattice Boltzmann models (LBM) is a recently developedmethod in computational fluid dynamics, and it is particularly suitable forflow modeling in complex boundary area. In this paper, the resistancecharacteristics of gas flow around two cylinders are numerically studiedusing LBM. The drag force and drag coefficient of each cylinder are studiedby varying the cylinder distance, Reynold number, and the attack angle.Three typical scenarios are studies: The first scenario is to calculate10 typical cases with the cylinder distance varying from 1.2d to 3.0d wherethe Reynolds number is fixed to be 20. The calculated results show that thesmallest stress acting on the downstream cylinder exists when the cylinderdistance is between 1.2d and 1.4d. Furthermore, the minimum total drag forceacting on the two cylinders occurs when cylinder distance is 1.6d. We alsofound that the downstream cylinder has no impact on resistance coefficientof upstream cylinder when the cylinder distance is greater than 2d. Thesecond scenario is to study the effects of Reynolds number on the resistancecharacteristics of the two cylinders by fixing the cylinder distance as1.2d. Results show that the weakest stress on the secondary cylinder intandem arrangement exists at a point where the Reynolds number is between 30and 40. The results in the third scenarioshow that the attack angle has great effect on the resistance coefficient ofeach cylinder. These reasonable results can server as the scientificfoundation for further research and implementation of flow overmulti-cylinders under low Reynold numbers.