# Animating a Vector Field

I am trying to create animations of a time dependent vector field $$\vec v(t,x,y)$$. The problem is that VectorPlot scales the vectors for each time $$t$$ separately based on the minimal and maximal norm of the vector field at that time.

This answer shows how to solve this problem using VectorScale in the case in which the ratio of the max. norm for some time $$t$$ and the the max. norm over all times is known. I suppose this could be found by evaluating $$\vec v$$ on a $$(t,x,y)$$ grid, but that makes for quite a lot of evaluations which I'd rather avoid. Surely there is a simpler way?

Try VectorScale this way:
Animate[

• But e.g. with the vector field 1/t {Cos[2 \[Pi] x + t], Sin[2 \[Pi] y + t^2]}, this will not reproduce the shrinking vector magnitudes correctly, which is what I am after. – Johannes R. Jan 6 at 22:56