what does divergence measure
The divergence of a vector field simply measures how much the flow is expanding at a given point. It does not indicate in which direction the expansion is occuring. Hence (in contrast to the curl of a vector field), the divergence is a scalar.he fact that fluid is flowing out of the sphere is a sign of the positive divergence of the vector field. Rotate with mouse to change perspective. You can move the sphere by dragging it with the mouse.