Irrotational flow means:

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Question

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JKSSB JE Mechanical 02 Nov 2021 Shift 1 Official Paper

Answer 1

Explanation:

Irrotational flow:

F1 S.S. N.J. 7.9.2019 D2

Irrotational flow is a flow in which no element of the moving fluid rotates in any direction from one instant to the next. Therefore, only a torque applied by shear forces on the sides of a fluid particle can cause it to rotate.
So, Irrotational flow means the net rotation of fluid particles about their mass center is zero.
Irrotational flow occurs when all of the tiny particles of fluid move along, translate, go around obstacles, and so on without ever rotating about their own infinitesimal centers of gravity. Irrotational flow can only continue if there is no viscosity.
Because shear forces do not exist in ideal fluids, their flow is essentially irrotational. When a flow is viscid, it tends to become rotational. This is because viscosity causes velocity gradients, as well as distortion and rotation of fluid particles, despite the fact that the fluid as a whole does not need to rotate around a fixed center. When the vorticity is zero everywhere, the flow is said to be irrotational.