Heat flow in liquid helium with clamped normal fluid

[摘要] With very few additional assumptions the wave equations forFirst Sound and Second Sound in liquid helium admit of simultaneous solution for the motion of both superfluid and normal fluid in the presence of a large viscous force on the normal fluid. If these fluids are set in motion by the presence of heat energy their consequent motion, through a viscous medium, is a mixture of two modes - a diffusive heatflow and a wave heat flow. These experiments aim at seeking each of these modes and examining them. It was found that the only observable heat was transmitted diffusively although a very high degree of experimental sensitivity to waves was reached. The investigation includes heat transmission by both pulses and monochromatic waves and theviscous medium varies from coarse emery powder to very tightly packed rouge. The measurements were carried out at temperatures from 1.3°K to the lambda point. The consequences of the absence of waves are analyzed.

[发布机构] University:California Institute of Technology;Department:Physics, Mathematics and Astronomy

[关键词] Physics