If S is a general material surface in a flow in the space, we show the relationship between the three components of the vorticity field on S and the curvatures of the streamlines of the tangential component of the velocity field (geodesic torsion, normal curvature, and geodesic curvature); and we show the relationship for the case of a general free surface. We present geometric formulae relating vorticity flux, from S, and curvatures of S (Gaussian curvature, mean curvature, curvatures of the streamlines of the tangential component of the velocity field); and we show the formulae for the case of a general free surface.

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