Comparison of schlieren-based techniques for measurements of a turbulent and wavy free surface

Abstract The free surface at an air–water interface can provide information regarding bathymetric complexities, as well the subsurface flow. We present a comparison of performance two recent advances in light-based optical techniques for measurements, total internal reflection-deflectometry and moon-glade background-oriented schlieren, with more established method synthetic schlieren. make use flow algorithm over traditional digital image correlation, order to obtain higher spatial resolution data across imaged domain. presents additional benefits, such computational efficiency robustness capturing large displacements straining tracked features. three are assembled synchronization conditions: (1) being impinged upon by underlying turbulent, free-shear (2) random irregular wave field induced jet. Using high-resolution we insight on emergence multiple dynamics turbulent surface. comprehensive discussion benefits drawbacks each technique, including suggestions suitability technique several experimental constraints. Graphical abstract