Light Sheet Technique

The light sheet technique is commonly used in water tanks in conjunction with air-bubble seeding. Application of the light sheet technique to flow visualization requires simultaneous implementation of the following items: realization of the light sheet, flow seeding, contingent auxiliary illumination, and choice and location of the camera. The light sheet visualization technique requires convenient flow seeding. This seeding may be done either by tracer injection from the model wall or by injection within the flow by means of a seeding pipe. In both cases, the emission point has to be precisely localized in order for the tracer to effectively seed the whole part of the flow that is of interest. The tracer species used most frequently in large wind tunnels are oil or kerosene smokes. Also used is steam generated from condensation of humid air meeting cold nitrogen in a liquid or gaseous phase.