A current divides around an obstacle and rolls into alternating vortices. Drag the obstacle and watch its wake reorganise into fine, circulating contours.
Vortex-street-inspired streamfunction
A cylinder-flow streamfunction is combined with a travelling street of smooth vortices. The field is an illustrative divergence-free construction, not a numerical fluid solver. Lines follow equal streamfunction values. Vortex pairs repeat every eighteen seconds.
flowwave