He also reports seeing an intermittent rushing of fluid upstream from the leading edge of the protuberance in a 'jet' close to the wall.
In its shell guise, the spiral usually has small protuberances around the perimeter.
In this case, an atypical electron-dense material surrounding the vesicle and forming a protuberance has never been described before.
The protuberances therefore represent the inflated margins of the alveoli dentalis.
The hairpin vortices were generated by a hemispheric protuberance and the injection of fluid into the boundary layer.
Only a 5 mm wide area of facies buccalis of the left ramus has been cleaned in order to expose the row of protuberances.
Upstream of the protuberance the time-averaged direction of the boundary-layer vorticity is spanwise across the surface.
The protuberances should exert a comensurate repulsion of the flow.
