Profilometry of a liquid-free surface with large slope variations

摘要

We describe and test a refractive method for determining the height profile of an unsteady liquid-free surface, which is adequate for regions where the slope of the surface changes strongly, as for example the head of a spreading current. The method is developed for situations in which the height depends on a single Cartesian coordinate (plane flows); however, the underlying idea could be applied to more general cases. As a test, we obtained the profiles of a transparent solid object (a cylindrical lens l and of an actual liquid flow. These profiles are determined with high accuracy even if the direction of the normal to the free surface changes approximately 150° within the probed region.# 1997 Optical Society of America