Abstract: The flow and heat transfer characteristics of a semi-confined laminar impinging square jet are investigated numerically by using the solution of the steady-state three-dimensional Navier-Stokes and energy equations for incompressible flows. Numerical results are presented to analyze the mechanism of the formation of the four streamwise velocity off-center peaks in jet. The effects of inlet Reynolds number and plate-to-plate spacing on jet flow-field structure and heat transfer characteristics are examined in the laminar range. The calculated results show that heat transfer performance of the impinging jet is dominated by the flow structure. It is the for-mation of the four off-center velocity peaks at the horizontal cut planes near to the impingement surface that results in the formation of the four temperature off-center minima at the cor-responding cut planes and the formation of the four off-center peaks of the local Nusselt number at the impingement surface.

Key words: Heat transfer characteristics, Numerical simulation Off-center peaks, Square impinging jet