Dissipation in super fluidity of (He-4-II)

It is believed that superfluidity arises in liquid He4at temperature T≤2.17 k. This property is signaled by the absence of Viscosity and Entropy. Therefor, the non-viscous flow of superfluid is expected to be without dissipation. But, several observations show that when superfluid velocity exceed the so called critical velocity. v s,c dissipation setting owing to the Mutual friction force (Gorter-Melink force). In the following we have studied this effect by means of Entropy production rate. We have shown that despite of friction flow dissipation. Occures due to the generation of vortices, which arises because of turbulent regime