The present paper studies the impingement of compressible air jet on a flat plate primarily from the aspect of its application in the domain of pneumatic metrology, i.e. in cases of small distance between the jet nozzle exit and the flat plate. Besides this direct application in the area of pneumatic metrology, the distance between the nozzle exit and the flat plate has been considerably increased and the case of a free jet was analysed with a view to compare the results applicable in various domains. This experimental study demonstrates that the structures of a free jet and this special case of an impingement jet are totally different. In the pressure distribution of the impingement jet, pressure discontinuity above the flat plate may occur, which is shown to be the result of low intensity shock waves and transonic flow. The experimental results show that the pneumatic sensitivity of a pneumatic comparator is a function of the supply pressure and the internal orifice diameter, as well as that the impingement air jet is a typical case of non-isentropic flow.

本文主要从其在气动计量领域中的应用方面，即在喷嘴出口和平板之间的距离较小的情况下，研究可压缩空气在平板上的撞击。除了在气动计量领域中的这种直接应用之外，喷嘴出口和平板之间的距离已大大增加，并且对自由射流的情况进行了分析，以比较适用于各个领域的结果。这项实验研究表明，自由射流的结构和这种冲击射流的特殊情况是完全不同的。在冲击射流的压力分布中，平板上方可能会出现压力不连续现象，这是由于低强度冲击波和跨音速流动造成的。