Reverse of laminar-turbulent transition in a supersonic underexpanded microjets

The results of measurements of supersonic length of underexpanded microjets outflowing into the atmosphere, by Pitot tube and the millimeter-diameter jets outflowing into low pressure chamber on the laminar and turbulent regimes are presented. Measurements of the supersonic length were supplemented with measurements of the mass flow rate pulsations on the jet axis by hot-wire anemometer and schlieren-visualization of the flow field. Experiments were conducted under the equal/approximately equal Reynolds number of micro - and millijets. It was found the restoration of laminar flow in jets at a certain values of the jet underexpansion (Reynolds number of the jet).