ABSTRACT
The Wolf River emerges from the Black Forest and winds across the snow-covered land. Its water is so cold it is syrupy, a snowball gets carried several yards before it melts. Chunks of ice floating downstream curve gracefully around bends. Fluid particles move along smoothly, their velocities varying between orderly bounds. But then they encounter an obstacle, and their streamlines begin to break down. The river carries on, even though mathematically, a solution to its flow equations cannot be found.
