Impact of cylinder corner modification on fluid dynamics and heat transfer: Corner cut size and cut angle

The impact of corner modifications on fluid dynamics and heat transfer characteristics of a square cylinder is numerically investigated at a Reynolds number Re = 150 (based on cylinder width W), with corner cut size C* (= C/W) = 0-0.5 and cut angle alpha = 0 degrees-45 degrees, where C is the corner cut size. The corner cut modification gradually modifies the baseline square cylinder (C* = 0, alpha = 0 degrees) to a number of octagonal and hexagonal shapes and finally to a diamond cylinder (C* = 0.5, alpha = 45 degrees) through a total of 64 distinct shapes. The focus is given on the dependence on C* and alpha of time-averaged and fluctuating flow fields around the cylinders, Strouhal numbers, fluid forces, and time-mean Nusselt numbers. Results of fluid forces and Nusselt number are also compared to those of circular cylinders at the same Reynolds number. Time-average and fluctuating fluid forces are reduced for several modified shapes compared to the baseline case, with some modifications yielding forces even smaller than those observed for the circular cylinder. Heat transfer improves for all modified shapes relative to the baseline square cylinder yet remains lower than that of the circular cylinder. The time-averaged flow fields reveal three distinct wake patterns depending on C* and alpha. The study identifies several shapes with improved fluid dynamic characteristics that can be applied in mechanical, civil, and environmental engineering applications.