Turbulent Inflow Generation Through Buoyancy Perturbations with Colored Noise

摘要

An inflow generation method for large-eddy simulations of wall-bounded turbulent flows is presented. The method builds upon the work ofMunoz-Esparza et al. ("A Stochastic PerturbationMethod to Generate Inflow Turbulence in Large-Eddy Simulation Models: Application toNeutrally StratifiedAtmospheric Boundary Layers," Physics of Fluids, Vol. 27, No. 3, 2015, Paper 035102). In the present adaptation of the original idea, colored noise is generated in the temperature field by adding white noise as source term perturbations in the filtered form of the temperature transport equation. Perturbation boxes introduced within a buffer zone near the inlet encompass multiple computational cells to induce a volumetric buoyancy effect. The amplitudes of the source term perturbations are determined by assigning a bulk Richardson number based on the size of the perturbation box and the height-dependent velocity profile. The temperature field with colored noise is then coupled to the incompressible flowfield within a buffer zone only via the Boussinesq approximation. A turbulent-channel flow and a backward-facing step with a spatially evolving boundary layer upstream of the step are simulated to assess the predictive performance of the inflow generation technique. The results are in good agreement with direct numerical simulation benchmark data, both for the first- and second-order statistics of turbulence. It is also found that the same set of parameters works well in both cases studied.