壁面せん断流中の物質拡散の研究 : 第1報,円管内壁面点源プルームの相似性

The aim of this study is to elucidate experimentally the spatial structure and the statistical properties of the plume diffusion field of matter from a wall point source in a turbulent pipe flow. The fully developed water turbulent flow of Reynolds number 20000 has been realized in the horizontal straight pipe of inner diameter 100 mm. The concentration field downstream from a continuous point source on the wall has been measured using a reflection-type fiber optic probe (sampling volume s 6.3×10-6cc). It is found that the vertical profiles of the mean concentration and concentration fluctuation r. m. s. value at the different downstream positions from the source show self-similarity on the symmetric plane of the diffusion field. In particular, the mean concentration profile can be described quite well by the universal function which was suggested for a point or a line source plume in the turbulent boundary layer on the flat plate.