Curl

How much it swirls

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Curl = ∂Q/∂x − ∂P/∂y: twice the local spin rate.
• Straight shear flows can have curl; circling vortices can have none.
• Gradient fields have zero curl.

Steps

1. A paddle wheel
2. Curl of a whirl
3. Find the calm spot
4. A whirlpool without spin
5. Curl of a shear
6. Curl and potentials