Given velocity vector {\vec {u}}=(u,v,w) the streamlines is a bunch of 3D space curves {\vec {r}}_s = \big( \, x_s, \, y_s, \, z_s \, \big) \in \mathbb{R}^3, parametrized by real number s, and solving the following equation:
{dx_s \over u} ={dy_s \over v}={dz_s \over w} |