抄録
The application of a laser Doppler velocimeter (LDV) is successfully attempted to He II jet, which is produced by pushing bellows, by employing neutral buoyant H2-D2 solid particles as scattering tracers. The LDV measurement gives detail information of the normal fluid velocity in He II with high temporal and spatial resolution. It was found that the normal fluid velocity in circular He II jet could be measured at least up to 15cm/s by the LDV without any appreciable degradation. The fluiddynamic behaivor of He II jet was found as the result of the present measurement to be similar to those of the turbulent jets of usual viscous fluids.
