Effect of Plane Boundary Layer on Air Flow Around Two Circular Cylinders in Tandem Arrangement

A two-dimensional numerical simulation was carried out using Ansys-fluent for air flow around two circular cylinders placed in tandem arrangement near a plane wall at a constant Reynolds number (Re≈7000) and for horizontal distance ratios (L/D = 1.2, 1.5, 2,3), and for gap ratios (G/D=0.2,0.5,1,2), and the thickness of the boundary  layer was relative to the location of the first cylinder (δ/D = 0.95), and the turbulence model (κ-ω SST) was chosen to simulate the flow near the surface of the two cylinders, the diameter of cylinder=0.01m. The results showed that there is no shedding of vortices at gap ratios (G/D=0.2) and for all distance ratios (L/D), and vortices shedding from the first cylinder at gap ratios (G/D=0.5,1,2) and for distance ratios. (L/D=2,3), and the second cylinder’s drag coefficient has a negative value for the distance ratios (L/D=1.2,1.5) due to the second cylinder being in the low-pressure region of the first cylinder and at vortex shedding from second cylinder only the lift coefficient of second cylinder greater than first cylinder and when vortex shedding from both cylinders the lift coefficient of first cylinder greater than second cylinder.