抄録
Two-fluid hydrodynamics is extended to three-fluid hydrodynamics including the “vortex fluid”, which denotes the system of vortex lines with the inertia mass of the vortex core. Characteristic constructions of hydrodynamics are considered in two typical configurations of vortex lines: one is the parallel vortex line configuration realized by rotating helium inside a cylinder, the other is the tangled configuration of vortex lines realized in turbulent pipe flow. Constitutional equations for three-fluid hydrodynamics are discussed for each configuration, including the equation of motion for momentum density proportional to the inertia mass of vortex fluid. By taking the vanishing limit of inertia mass, a condition is derived whereby the total force exerted on the vortex line vanishes, and the extent to which the three-fluid model approaches the two-fluid hydrodynamics in this limit are discussed.
