A Simplified Low-Reynolds-Number One-Equation Model of Turbulence

X. Wu and Y. Nagano (Japan)


Turbulent flow, one-equation model, computational fluid dynamics.


In this study, we simplify the low-Reynolds-number (LRN) one-equation model for eddy viscosity proposed by Nagano et al. [1] because the model comprises a great number of wall-reflecting terms which are model function originated, highly nonlinear, and predominantly singular in the vicinity of the wall. These terms can have a very negative influence on the stability and convergence of nu merical simulations and can make the implementation of the model very difficult for complex flows of engineering interest. We simplify the model by removing these terms and making adjustments to the model constants and func tions. The simplified model is tested in the calculations of channel flows at various Reynolds numbers and boundary layer flows with/without pressure gradients. The predicted results are compared with available direct numerical sim ulation (DNS) or experimental data. It is shown that, al though simplified, the model reproduces the correct wall limiting behavior of turbulence and generally gives good predictions for the flows. Without the wall-reflecting terms which appear in the original model, It is more robust and easier to integrate. The model is sure to have great advan tages when applied to complicated turbulent flows.

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