Numerical analysis of fluid forces for flow past a square rod with detached dual control rods at various gap spacing

A two-dimensional numerical study was conducted for flow past a square rod in the presence of two control rods. One is placed vertically in the upstream direction and the second one is placed horizontally in the downstream direction of the square rod. The influence of gap spacing was studied by taking g₁ = 1-5 and g₂ = 0.5-5 (where g₁ is the gap between the upstream control rod and the main rod, and g₂ is the space between the main rod and the downstream control rod) at Re = 160. The simulation results were obtained in the form of vorticity contour, drag and lift coeffcients, Strouhal number, and force statistics. Under the effect of gap spacing, three different flow modes were found and named according to their behavior. It was found that the mean drag coeffcient showed decreasing behavior by increasing the value of g₂ continually at a fixed value of g₁. The largest value of Cdmean was found at (g₁, g₂) = (1, 1) and the greatest percentage reduction in Cdmean was obtained at (g₁, g₂) = (1, 3), which is 139.72%. The effect of thrust was also noticed for all selected values of g₁ and g₂. Furthermore, it was noticed that the Strouhal number and the root mean square values of the drag and lift coeffcients smaller values than the single rod values, except for the Clrms value of (g₁, g₂) = (1, 3) and (1, 4).