Two-dimensional turbulent parallel pipe flows have been studied by directly solving the Navier-Stokes equations of motion(1)(2)(3). However, there was a problem that disturbances were generated and developed, causing the solution to diverge. This problem was prevented by increasing the viscosity of the cells that were prone to divergence. It was investigated whether the method used for two-dimensional pararel pipe flows could be applied to simulate three-dimensional pararel pipe flows. It was found that the method was effective for three-dimensional pararel pipe flows. The calculated value of the pipe friction coefficient was larger than the value at the set Reynolds number, but was almost the same as the value at the average internal Reynolds number.
Masahiro IWANAGA (Wed,) studied this question.