Whole-field density measurements by ‘synthetic schlieren’

摘要: This paper outlines novel techniques for producing qualitative visualisations of density fluctuations and obtaining quantitative whole-field measurements in two-dimensional density-stratified flows. These techniques, which utilise image processing technology, are much simpler to set up than the classical schlieren interferometry methods, provide useful information situations where shadowgraph is little or no value. Moreover, they may be set-up analyse larger domains feasible with approaches, do not require high quality optical windows experimental apparatus. Ultimately greatest strength these ability extract accurate, field. Application illustrated by an internal wave field produced oscillating cylinder. Recent theoretical advances this problem make it ideal test bed. Results presented both a circular square cylinder vertically linear stratification. Further aspects considering thermal convection from hand flow over obstacle towed through stratified fluid.