Irrotational Vector field
A vector field vector F is said to be irrotational vector if curl of F is equal to zero ▽ x F =0 Irrotational Vector field Concept The Above phenomenon is due to Irrotational vector Field. Explanation Of above picture: Side wheels indicated as red arrow and white arrow are rotating in the direction of Anti-Clockwise and Clockwise respectively Red arrow- (Wheel)->Anticlockwise White arrow-(wheel)-> Clockwise Why Middle wheel does not rotate? Answer: Middle wheel does not rotates because the flow of water to the surface of wheel does not allow to move. Why does side wheels rotate? Answer: Because at the side of river the speed of flow of water is very low as compared to in the center of the river. Disclaimer: If you want to give feedback or Your point of view on this discussion please write us in the comment below.