Numerical Analysis of Developing Turbulent Flow in a Curved Pipe.

Abstract

Numerical analysis has been performed for three-dimensional developing turbulent flow in a curved pipe with contraction inlet by using an algebraic Reynolds stress model. Special attention is paid for the developing turbulent flow in curved pipe under the condition that the intensity of fluctuating velocity is low value at the inlet cross section of curved pipe. Such developing turbulent flow plays an important role in several engineering fields as well as a fully developed turbulent flow. In calculation, algebraic Reynolds stress model is adopted in order to predict preciously Reynolds stresses and boundary fitted-coordinate system is introduced as the method for coordinate transformation to set boundary conditions along complicated shape of curved pipe. Calculated results are compared with the experimental data in order to examine the validity of the presented numerical method and turbulent model. As for the comparison of mean velocity, the calculated results are relatively good agreement with the experimental data and are able to reproduce characteristic features observed in developing turbulent flow. By contrast to the comparison result of mean velocity, it is found that the present calculation has a tendency to overestimate the value of turbulent energy in a curved pipe region. Adding to this, it is pointed out as a characteristic feature that the region with high intensity is generated near inner wall region which phenomenon is also recognized in mean flow field.