Modeling turbulent diffusion in a rotating cylindrical pipe flow

Abstract

The influence of accuracy of the turbulent diffusion model (TDM) included in the Reynolds stress transport model (RSTM), on describing the behavior of the mean velocity components as well as the Reynolds stresses has been studied for an isothermal incompressible flow in a rotating cylindrical pipe. RSTMs used usually in practice, cannot reproduce correctly the behavior of statistical characteristics along the rotating pipe axis, in particular. Because of strong inhomogeneity of the flow, one of the reasons of the RSTM shortcomings could be insufficient accuracy of TDMs. A new tensor-invariant model for the triple velocity correlations, describing satisfactorily their behavior over the whole flow field, from the pipe axis to the wall, has been developed by the authors. Testing the standard RSTM with the different TDMs in a rotating pipe flow shows that for calculating the first- and second-order moments, the important characteristic of the TDM is its tensor-invariance. The mean velocity components are mostly influenced by the model for the pressure–strain correlations. Application of more accurate TDM creates the basis to improve models for the pressure–strain correlations and the dissipation tensor, and, finally, get the RSTM applicable to a wide range of turbulent flows.