Visualization of a mechanism for three-dimensional interaction and near-wall eruption

An experimental configuration has been found which allows detailed observat ion of three-dimensional vortex-vortex and associated vortex-surface intera ctions which appear similar to those observed in fully turbulent flow. Hydr ogen bubble visualization illustrates a complicated intertwining, or braidi ng, of two initially co-rotating vortices. It is observed that the three-di mensional interactions of the braided vortices induces a pair of local surf ace-fluid eruptions reminiscent of the 'bursting' behaviour characteristic of the near-wall regeneration process of fully turbulent boundary layers.