Numerical studies towards practical large-eddy simulation

TL;DR

This paper presents numerical methods and validation for large-eddy simulation of turbulent internal flows, emphasizing adaptability to complex geometries and improved accuracy in mean flow and turbulence spectra.

Contribution

It introduces an adaptable finite volume LES method with higher order fluxes and exponential averaging, suitable for complex geometries and unsteady flows.

Findings

Consistent results on academic test-cases validate the method.

Exponential averaging shows promise for LES in complex geometries.

Method successfully applied to turbomachine blade-tip clearance flow.

Abstract

Large-eddy simulation developments and validations are presented for an improved simulation of turbulent internal flows. Numerical methods are proposed according to two competing criteria: numerical qualities (precision and spectral characteristics), and adaptability to complex configurations. First, methods are tested on academic test-cases, in order to abridge with fundamental studies. Consistent results are obtained using adaptable finite volume method, with higher order advection fluxes, implicit grid filtering and "low-cost" shear-improved Smagorinsky model. This analysis particularly focuses on mean flow, fluctuations, two-point correlations and spectra. Moreover, it is shown that exponential averaging is a promising tool for LES implementation in complex geometry with deterministic unsteadiness. Finally, adaptability of the method is demonstrated by application to a configuration representative of blade-tip clearance flow in a turbomachine.