Author(s): Yo Kumagai; Hitoshi Tanaka
Linked Author(s): Hitoshi Tanaka
Keywords: K-turbulence model; Grid topology; Circular pipe flow; DNScomputational hydraulics
Abstract: In a numerical analysis of turbulent flow with a boundary fitted coordinate system, dependence of computation accuracy on grid system should be fully considered. Up to now, many computations have been carried out for various kinds of hydraulic structures using curvilinear coordinate, though, there have been no subjective and quantitative criterion for the choice of grid system which yields sufficient accuracy. In this study, an analysis for a flow in a circular pipe is made and compared with direct numerical simulation (DNS) data, in order to evaluate the dependence of computation accuracy on grid topologies. A grid distortion parameter is newly introduced in the present study and the relationship between and the accuracy of corresponding computation is discussed. It is found that a grid system which satisfies >0.7in the region of y+<20 produces a considerable error when a low Reynolds kturbulence model is applied.