The fundamental structure as well as several important success in modern fluid mechanics were described briefly in relation to the future advances in engineering use of cryogenic fluids to be accomplished by sophisticated techniques of the transfer, the distribution and the storage of cryogenic fluids. The problems mentioned include pressure-drop, hydrodynamic instability, critical flow, thermal stratification, sloshing and thermal explosion.
Experimnents were made on pressure drop of liquid nitrogen flow in concentric annuli. The Reynolds number based on hydraulic diameter and mean velocity ranged from 200 to 18, 000. As a result it was found that the relation between Reynolds number and friction factor showed good agreement with the data previously obtained for newtonian fluid at room temperature.
Losses in single- and multi-core superconducting composite conductors were studied experimentally in the range from 20 to 500Hz and below the current of 100A. Composites consist of Nb-60.8 Ti-2.8 Zr ternary superconducting alloy embedded in Cu matrix. Volume of He gas evaporated by the loss when sinusoidal current was passed through the wire was measured. A mechanism of the loss was investigated using a frequency dependence. The single-core composite generates the hysteresis loss in the superconductor and the eddy current loss in Cu matrix. The loss in the multi-core composite is expressed in terms of the hysteresis in an equivalent superconductor which has same volume of superconducting filaments involved and the eddy current loss in an outer region of Cu matrix.