Axisymmetric impinging jet excited by a synthetic jet system

The effects of the Strouhal number and nozzle-to-wall spacing on a distribution of the local heat transfer were evaluated. The most significant effects were found at the Strouhal numbers 0.14-0.32 at the ratio of the control to primary jet momentum rates only 0.24-2.4%. Under small nozzle-to-wall spacing H/D = 2, the excitation led to heat transfer increase in the stagnation area - the most prominent enhancement 40% was found at the stagnation point. Under moderate nozzle-to-wall spacing H/D = 6, the excitation made more uniform the Nusselt number distribution by means of a substantial reduction of the stagnation heat transfer rate.