Abstract
In order to improve the performance of heat transfer with multiple impinging jet(MIJ), we investigate the DNS (direct numerical simulation) of four round impinging jet arranged at an inflow of flow field. As a control parameters, a separation between each jet is varied. From view of instantaneous vortical structures and time-averaged velocity distribution, it reveals that the generation of vortical structures are enhanced due to an interaction between each jet, compared to that of a single impinging jet, and that various type of upward flow which does not exist in the single one, appears according to the control parameter. In addition the heat transfer performance of MIJ is numerically turn out.