have a little look around about pulsed jets. The main cases available are air jets but for either case it was found that pulsing created large eddies whihc improved turblence of the jet. However this turbulence resulted in a lowering of overall heat transfer performance. At the center of the jet (distance from the center of the jet) heat transfer was lost signficantly however further away from the jet more heat was transfered due to higher turbulence.
At jet heights over 15d you lose any beinfits. The highest benfical effects would occur at distances of 3d as here the flow is axisymetric.
One interesting point is that pulsed jets show much lower pressure drop. A jet amplitude of 5% (flow 100% to 95% of max flow rate) created a lower pressure drop of 7%
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