Retroreflection focusing schlieren system

摘要

A retroreflective type focusing schlieren system which permits the light source to be positioned on the optic side of the system. The system includes an extended light source, as opposed to a point source, located adjacent a beam splitter which projects light through the flow field onto a reflecting grating in the form of a grid which generates sheets of light that are directed back through the flow field and the beam splitter onto a primary lens behind which is located a cut-off grid having a grid pattern which corresponds to the grid pattern of the reflecting grating. The cut-off grid is adjustably positioned behind the primary lens and an image plane for imaging the turbulence is adjustably located behind the cut-off grid.