Numerical analysis of laminarizing circular tube flows by means of a Reynolds stress turbulence model

An attempt is made to simulate the laminarization phenomena of strongly heated gas flows in a circular tube by means of the Reynolds stress turbulence model by Launder and Shima. Numerical results show that the adopted model can generally reproduce the streamwise variation of the Stanton number of laminarizing flows, while the prediction accuracy is comparatively poor particularly in the subtle stage of turbulent-to-laminar transition region. It is also found that, when the flow is laminarized due to strong heating, radial and peripheral components of the normal Reynolds stress are preferentially attenuated and, consequently, the inherent anisotropy of the circular tube flow is relatively amplified