Author(s): Shunichiro Hayashi; Terunori Ohmoto
Linked Author(s): Terunori Ohmoto
Keywords: DNS; Regular grid system; Generalized curvilinearcoordinate; Free surface turbulence
Abstract: A direct numerical simulation method using a regular grid under a generalized curvilinear coordinate system is presented which can reproduce flows in complex geometry. In this paper, at first a one-dimensional linear convection problem was dealt to investigate the accuracy. The results showed that the way of defining a grid with certain types of unequal spacing cause substantial phase errors in numerical solutions and the cause is the metric discontinuity. Next, a regular grid under a generalized coordinate system was used to analyze free surface turbulent flow with Reynolds number 150 defined by friction velocity. It was shown that this method enabled sufficiently stable calculation. In addition, a comparison with DNS of open channel flow using a staggered grid verified that this simulation gave fairy satisfactory properties with respect to high order moments of velocity fluctuations.
Year: 2001