Flow around a square prism between two parallel walls

A numerical investigation is conducted on the fluid flow around a square prism (of height d) symmetrically placed in a rectangular channel. The primary objective is to explore the effects of prism-wall gap spacing g^* = g/d (= 0.5–12.0) on flow dynamics, vortex shedding, and aerodynamic forces at a fixed Reynolds number Re = 100, where g is the spacing between the prism and the channel wall. The Strouhal number, time-mean drag coefficient, and base pressure coefficient all exponentially increase when g^* decreases from 12 to 0.5. The fluctuating lift coefficient, however, decreases for g^* from 0.5 to 1.0, increases for g^* from 1.0 to 2.2, and again decreases for g^* = 2.2–12.0. It is inversely correlated with vortex formation length. Four distinct flow regimes are identified: (i) wall vortex street (g^* < 0.9), (ii) reversed Kármán vortex street (0.9 < g^* < 2.9), (iii) aligned vortex street (2.9 < g^* < 4.2), and (iv) Kármán vortex street (g^* > 4.2).