Studying crowd dynamics could inform strategies that help to prevent dense gatherings from becoming dangerous.

For example, a cylinder in the flow of an inviscid fluid has no vortex shedding and it has no drag, contrary to our practical experience. Return to Aerodynamics of Bicycles Introduction.

The main look to the upper-air weather pattern is a subtle change to a southwesterly flow ... vortex swings around the main body of the polar vortex. You can see that idea here in this model ...