Experimental investigation into shock waves formation and development process in transonic flow

An extensive experimental investigation was performed to explore the shock waves formation and development process in transonic flow. Shadowgraph visualization technique was employed to provide visual description of the flowfield features. Based on the visualization, the formation process was categorized into two intrinsically different phases, namely, subsonic and supersonic. The characteristics of subsonic phase are well known; however, those of the supersonic one are far less studied. The supersonic phase itself is made up of two consecutive phases, namely, approaching and sweeping. The effects of each phase on the flowfield characteristics and on shaping the supersonic regime were studied in details. In order to generalize the results, three different models were tested. A special terminology is suggested by authors to ease the process description and pave a way for future studies. Above all, as the transition from transonic regime to the supersonic one is a vague concept in terms of physical reasoning, a new explanation is proposed that can be used as a criterion for distinguishing between transonic and supersonic regimes