Mach-Zehnder Technique Research Articles

Experimental Study on Oscillation of Underexpanded Impinging Jet and Behavior of Plate Shock Wave.

In order to investigate the oscillation of an underexpanded impinging jet and the behavior of plate shock wave in the vicinity of a plate, we visualize the flow field mainly using the Mach-Zehnder technique and measure the pressure on the plate. At a nozzle pressure ratio of 3.0, the shape of the plate shock wave changes periodically with nozzle-plate spacings. However, when the spacing exceeds a certain value, the type of oscillation changes markedly. The change of oscillation is confirmed by interferograms and pressure measurements. Comparing the jet structure with the oscillation, the change can be considered to be caused by instability of the jet boundary.

A study of the prebreakdown phenomena in liquefied nitrogen using optical observation systems

The movement of the disturbance due to electric charge carries in liquefied nitrogen is investigated by four optical using systems. The mobility of the electronic charge carriers derived from the drift velocity of the disturbance is in the range of 0.1—0.4 cm 2/V s which is two or three orders of magnitude larger than that of negative ions and also two or three orders smaller than that of free electrons. Thus, the result has been discussed from the point of view of hopping transport mechanism. The sensitivity of the present optical systems was measured by using a Mach-Zehnder technique.