New method for visualizing 3-D vortices structures using sectional data

Several methods for visualizing the flow structures by using sectional data were compared and analyzed to find the reason why sectional streamlines cannot describe vortices structures correctly. Consequently a new concept of defining the sectional spin vector by the vector product of Lamb vectors and normal vector of the section is proposed. Comparing with other methods, the visualized structure of the flow field described by the spin vector is more correct because the sectional cross-lines of the Lamb surface and the observational plane as described by the suggested method do not distort the visualized flow phenomena even the observational plane is not properly chosen.