Numerical Analysis of Three-Dimensional Turbulent Flow in a 180.DEG.-Bent Tube Using by an Algebraic Reynolds Stress Model.

Abstract

A numerical analysis has been performed for three dimensional developing turbulent flow in a 180° bent tube with straight inlet and outlet sections using by an algebraic Reynolds stress model. To our knowledge, only very few numerical investigations exist in which the detailed comparison between calculated results and experimental data contained Reynolds stresses. In numerical analysis, an algebraic Reynolds stress model in conjunction with a boundary-fitted coordinate system is applied to a 180° bent tube in order to solve the anisotropic turbulent structure precisely. As a result of this analysis, it is found that the calculated results show a comparatively good agreement with the experimental data of the time averaged velocity and the secondary vectors in the bent tube and the straight outlet sections. For example, the location of the maximum streamwise velocity, which appears near the top or bottom wall in the bent tube, is predicted correctly by the present method. As for the comparison of Reynolds stresses, the present model has been found to simulate many characteristic features of streamwise normal stress and shear stresses in the bent tube satisfactorily, but has a tendency to underpredict its value. Judging from the comparison between the calculated and the experimental results, the algebraic Reynolds stress model is applicable to the developing turbulent flow in a bent tube which is known as a flow with a strong convective effect.