He II熱カウンター流ジェットの流体力学的構造に関する研究

抄録

The flow structure of a thermal counterflow jet is investigated by direct measurement of the normal fluid velocity with a laser Doppler velocimeter (LDV). The temporal and spatial variation of the normal fluid velocity is measured to investigate the detailed nature of He II thermal counterflow jet. The velocity profile and the variation of the center-line velocity with the axial distance are also obtained to discuss the flow structure in a downstream region. It is found that the thermal counterflow jet in the far field behaves like a fully developed turbulent jet in ordinary fluids. It, however, seems that the way of development differs from that of ordinary fluid jets.