長方形断面を有する90°曲がり管路内乱流の応力場解析

概要

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A numerical study has been performed on turbulent flow developing in a 90 deg curved duct of retangular cross section and an aspect ratio of 6. The ratio of bend mean radius of curvature to hydraulic diameter is 2.04 and straight ducts of 7.5 and 25.5 width are attached to the inlet and outlet of the bend, respectively. In addition to this straight duct. two-dimensional lateral contraction of the wind tunnel with an area ratio of 6 is considered as the numerical domain as well as the experimental apparatus. Calculated results were compared with the experimental data measured for Reynolds stress components in detail. In this calculation, an algebraic Reynolds stress model was adopted in order to predict anisotropic turbulence precisely, and a boundary-fitted coordinate system was introduced as the method of coordinate transformation. As a result of this examination, the present method can predict normal and shear stresses distributions of the inlet straight duct but cannot reproduce the characteristic destabilizing effect and shows an increase in the turbulence intensity close to the outer wall in the curved duct. The discrepancy may be caused by use of the wall function as the boundary condition. In the outlet straight duct. the calculated value of normal and shear stresses are smaller than those of the experiments.
社団法人日本機械学会の論文
1997-04-25