壁面せん断流中の物質拡散の研究 : 第5報, 円管内壁面点源拡散の変動濃度場の局所相似性

In this report, we extend the similarity argument used in the previous report (1) to the mean square concentration fluctuation equation on the symmetrical plane of the wall point source plume in a turbulent pipe flow to find the similar solution for the mean square concentration fluctuation distribution. The main assumptions are the Lagrangean similar hypothesis and an appropriate eddy diffusivity distribution to the triple correlation term and the mixing length theory. It is found that the distribution of the similar solution shows good agreement with experimental data in a pipe flow. In the case of a wall point source in a turbulent boundary layer on a flat plate, the same argument is appliciable, and the similar solution obtained shows good agreement with the experimental data. And the budget of the fluctuating concentration intensity is investigated on the basis of the similar solution and the mean square concentration fluctuation equation.