Flow visualization and digital image processing of unsteady viscous diffusing free doublet

The object of the present study is to establish a new method for the automatic measurement of unsteady slow flow field with vortices, using a digital image processing system. The flow patterns of viscous diffusing free doublet are recorded on VTR. The two pictures of visualized flow at small time intevals Δt are stored in an image acquisition board. After bi-level quantitation, each image of objective tracer between the two pictures is identified by a new coorelation method. The velocity vectors and vorticity contour curves are dipicted, and the flow mechanism of doublet is explained like that the fluid arround a doublet convected with otherwise uniform flow is rolled and engulfed in it and that it diffuses gradually.