Constrained large-eddy simulation of laminar-turbulent transition in channel flow

Abstract

A constrained large-eddy simulation (CLES) of a laminar-turbulent transition in a temporally developing channel flow is performed. First, we confirm the capability of CLES to simulate this transition problem using the a priori Reynolds stress estimated from a direct numerical simulation. Based on the analysis of the Reynolds stress during the transition process, an intermittency factor is introduced in the Reynolds-averaged Navier–Stokes equation (RANS) model to account for the transition property. Two simple approaches are used to construct the intermittency factor. One is based on the shape factor, and the other is based on the coefficients of Smagorinsky models. The CLES results using the intermittency modified RANS model can accurately predict the onset of the transition and the basic transition process, in a manner similar to a large eddy simulation with dynamics Smagorinsky model (LES-DSM). Meanwhile, CLES preserves its advantage over LES-DSM in the turbulent state. The present work illustrates that CLES can be used to simulate transitional flows.

Recent progress in compressible turbulence

“…Our future work will be devoted to extending the CLES method to transitional problems. In fact, we have assessed the CLES method in a temporal transitional channel and demonstrated that the CLES has the ability to simulate transitional problems [17]. This work encourages us to apply the CLES in more complex transitional problems, for both incompressible and compressible flows.…”

“…It was shown that the CLES method could successfully eliminate the LLM defect and correctly predict the skin-friction coefficient in the attached channel flow, and its capability to simulate the detached wall-bounded flow is comparable to that of the DES. Recently, Zhao et al [17] successfully applied the CLES to simulate the laminar-turbulent transition problem in a temporal evolving channel flow.…”

“…In this paper, we will review some recent progress on compressible turbulence from the authors' group, including fundamental studies on compressible isotropic turbulence (CIT) and an engineering model of a constrained large eddy simulation (CLES) for wall-bounded turbulent flows. Details can be found in our recent papers [2][3][4][5][6][7][8] for the CIT and [9][10][11][12][13][14][15][16][17] for the CLES method and its validations and applications, respectively.…”

Assessment of the shear-improved Smagorinsky model in laminar-turbulent transitional channel flow

“…In the present study, the computation domain is selected as a cubic box with a size of 2π /1.12δ × 2δ × 2π /2.1δ (δ is the channel half-width), which is the same as the ones used by Gilbert and Kleiser, [39] Schlatter et al, [31] and Zhao et al [37]. Periodic boundary conditions are used in the wall-parallel plane (i.e., the streamwise (x) and spanwise (z) directions), while the non-slip boundary conditions are assigned at walls (y = ±δ).…”

“…[10][11][12][13][14][15][16][17][18][19] In theoretical research, a boundary layer or a plane channel was usually selected as the canonical problem. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] In the present study, a K-type transition in a plane channel flow is chosen as the test case to assess the SISM model.…”