Multiple time-surface characterization of time-dependent, three-dimensional flows
Certain features of the large-scale, time-dependent flow structure from an oscillating, three-dimensional body can be approximated by using combined hydrogen bubble visualization, video recording, and computer-aided design (CAD) reconstruction. This technique requires a single bubble wire and video camera in conjunction with a phase reference from the oscillating body to acquire two-dimensional projections of the flow at desired spanwise locations. In principle, this technique and its extensions can be employed for any unsteady, three-dimensional flow where a suitable phase reference exists. Appropriate generation of bubble timelines leads to three-dimensional “time-surfaces” at selected instants of time, and threreby a three-dimensional space-time estimate of the macroscale features of the flow.
KeywordsHydrogen Video Camera Flow Structure Video Recording Hydrogen Bubble
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