Karman vortex street parametrization with image processing application

The karman vortex street phenomenon is applied in the vortex flowmeter. Application of various methods of investigations is necessary in the course of getting increased knowledge of the phenomenon. Flow visualization being the leading method of aero- and hydrodynamic phenomena investigations enables qualitative evaluation in micro-scale. Due to the image processing application in analysis of flow visualization pictures, calculation of geometrical parameters of the Karman vortex street is feasible. So, the quantitative information is obtained. The worked out methodology of investigations as well as designed software for analysis of vortex street pictures are described in the paper. The results of the carried out laboratory tests are reported. Flow visualization has been carried out on the especially designed laboratory tests are reported. Flow visualization has been carried out on the especially designed laboratory stand. The visualized flow has been recorded on the magnetic tape and then processed into set of consecutive frames. Four groups of frames of similar vortex development phases have been put on the image processing procedure. Distances between adjoining vortices have been calculated. On the basis of obtained results it can be stated, that in spite of probabilistic nature of the investigated phenomenon strengthened by the applied research method (flow visualization), the proposed method enables quantitative determination of Karman vortex street parameters.