Which direction do whirlpools on a river eddy line spin?

Question

In a turbulent flowing river, an eddy is created when water is forced upstream. The area where the upstream and downstream flows meet is called the "eddy line", and whirlpools often form along this line. While looking downriver, suppose the downstream flow is on the left and the upstream flow is on the right. Where the flows meet, will the whirlpools that form spin in a clockwise direction as one might expect? Or will they form spinning the opposite direction? Will all of the whirlpools spin the same way?

Answer 1

Will all of the whirlpools spin the same way?

They will satisfy vorticity, i.e., the direction of rotation will be defined by $\nabla \times \mathbf{v}$. Take a flat object like the end of a paddle and pull it through the water. You will see two oppositely rotating vortexes on either side of the flat ends at the interface with the surface.

Where the flows meet, will the whirlpools that form spin in a clockwise direction as one might expect?

In the example given where one is looking parallel to the bulk flow and is on the right-hand side of the river (i.e., main flow on left and eddy pool on the right) then the rotation of the whirlpool will be clockwise.