This question relates to fluid mechanics and I have the components in polar coordinates. The components of the velocity field are; $$v_r= \frac{-kr}{z}$$ $$v_z= kz$$ $$v_\theta= 0$$ and I have solved for the streamline function and got;
$$\psi=-kzr^2$$
but I have no idea how to plot this so we can see the direction of the fluid flow. Any help would be greatly appreciated.