Reynolds-stress-constrained large-eddy simulation of wall-bounded turbulent flows

Abstract

In the traditional hybrid RANS/LES approaches for the simulation of wall-bounded fluid turbulence, such as detached-eddy simulation (DES), the whole flow domain is divided into an inner layer and an outer layer. Typically the Reynolds-averaged Navier–Stokes (RANS) equations are used for the inner layer, while large-eddy simulation (LES) is used for the outer layer. The transition from the inner-layer solution to the outer-layer solution is often problematic due to the lack of small-scale dynamics in the RANS region. In this paper, we propose to simulate the whole flow domain by large-eddy simulation while enforcing a Reynolds-stress constraint on the subgrid-scale (SGS) stress model in the inner layer. Both the algebraic eddy-viscosity model and the one-equation Spalart–Allmaras (SA) model have been used to constrain the Reynolds stress in the inner layer. In this way, we improve the LES methodology by allowing the mean flow of the inner layer to satisfy the RANS solution while small-scale dynamics is included. We validate the Reynolds-stress-constrained large-eddy simulation (RSC-LES) model by simulating three-dimensional turbulent channel flow and flow past a circular cylinder. Our model is able to predict mean velocity, turbulent stress and skin-friction coefficients more accurately in turbulent channel flow and to estimate the pressure coefficient after separation more precisely in flow past a circular cylinder compared with the pure dynamic Smagorinsky model (DSM) and DES using the same grid resolution. Furthermore, the computational cost of the RSC-LES is almost the same as that of DES.

Comment on “A hybrid subgrid-scale model constrained by Reynolds stress” [Phys. Fluids 25, 110805 (2013)]

“…8 The RSC-LES model of Chen et al was utilized to simulate both the turbulent channel flow and flow around a circular cylinder in Ref. 2. The results manifest that the model of Chen et al 2 shows very good performance in the predictions of the mean velocity distribution, friction force, pressure distribution, and other statistical quantities, and is only weakly sensitive to the grid resolution provided that the near-wall mesh is well designed.…”

“…2 The principle purpose of this comment is to address, through comparison, the connections, similarities, and differences between these two articles.…”

Joint-constraint model for large-eddy simulation of helical turbulence

“…[46], the variation process under an SGS dissipation constraint is helpful in improving the performance of a mixed dynamic model for simulation of driven and decaying isotropic turbulence. It was also shown that the inclusion of the near-wall Reynolds stress (and heat flux) constraint(s) in the SGS modeling allows the LES technique to simulate wall-bounded turbulent flows at moderate grid resolutions with promising accuracy [47,48]. Although the physical mechanism of the interplay between energy and helicity cascades still remains unclear, the effect of helicity has been taken into account for turbulence modeling.…”

Low-frequency vortex oscillation around slender bodies at high angles-of-attack

“…The bounded-centered scheme has successfully been applied to large eddy simulation in previous research. 26 The DMD code has been verified and validated using analytical synthetic solutions and the flow around a two-dimensional circular cylinder. The convergence of the DMD results with sampling snapshots has also been tested.…”

“…5,26 Since boundary layers are laminar before separation, the grid density within boundary layers is not necessarily required as much as the case for turbulent boundary layers in LES. The angles of attack are fixed at 50 • and 70 • .…”