Does friction exists between layers in fluid?explain?

Answer 1

Yes, Flows inside ducts, channels and pipes are very important because they occur in many practical applications (water pipes, air conditioning ducts, gas lines, ventilation shafts, heat exchanger tubes, etc.). Friction is usually important in these flows because there is a resistance to relative motion: when one layer of fluid is moving with respect to an adjacent layer, there exists friction between the layers. The amount of friction depends on the fluid viscosity and the velocity gradient (that is, the relative velocity between fluid layers). The velocity gradients are set up by the no-slip condition at the wall. When a fluid is in contact with a solid surface, there can be no relative motion between the fluid in contact with the solid surface and the surface itself: if the wall has zero velocity, then the fluid in contact with the wall has zero velocity also.

Answer 2

Yes.

Its called viscosity.