Numerical simulation of turbulent, plane parallel Couette–Poiseuille flow. (25th January 2023)

• Record Type: Journal Article
• Authors: Cheng, W.; Pullin, D.I.; Samtaney, R.; Luo, X.
• Is Part Of: Journal of fluid mechanics. Volume 955(2023)
• Publication Date: 2023-01-25
• Subjects: turbulence modelling -- turbulence simulation; Fluid mechanics -- Periodicals; 532.005
• DOI: 10.1017/jfm.2022.1023
• Languages: English
• ISSNs: 0022-1120

Abstract

Abstract: Abstract : We present numerical simulation and mean-flow modelling of statistically stationary plane Couette–Poiseuille flow in a parameter space $(Re, \theta )$ with $Re=\sqrt {Re_c^2+Re_M^2}$ and $\theta =\arctan (Re_M/Re_c)$, where $Re_c, Re_M$ are independent Reynolds numbers based on the plate speed $U_c$ and the volume flow rate per unit span, respectively. The database comprises direct numerical simulations (DNS) at $Re=4000, 6000$, wall-resolved large-eddy simulations at $Re = 10\, 000, 20\, 000$, and some wall-modelled large-eddy simulations (WMLES) up to $Re=10^{10}$ . Attention is focused on the transition (from Couette-type to Poiseuille-type flow), defined as where the mean skin-friction Reynolds number on the bottom wall $Re_{\tau, b}$ changes sign at $\theta =\theta _c(Re)$ . The mean flow in the $(Re, \theta )$ plane is modelled with combinations of patched classical log-wake profiles. Several model versions with different structures are constructed in both the Couette-type and Poiseuille-type flow regions. Model calculations of $Re_{\tau, b}(Re, \theta )$, $Re_{\tau, t}(Re, \theta )$ (the skin-friction Reynolds number on the top wall) and $\theta _c$ show general agreement with both DNS and large-eddy simulations. Both model and simulation indicate that, as $\theta$ is increased at fixed $Re$, $Re_{\tau, t}$ passes through a peak at approximately $\theta = 45^{\circ }$, while $Re_{\tau, b}$ increases monotonically. Near the bottom wall, the flow laminarizes as $\theta$ passes through $\theta _c$ and then re-transitions to turbulence. As $Re$ increases, $\theta _c$ increases monotonically. The transition from Couette-type to Poiseuille-type flow is accompanied by the rapid attenuation of streamwise rolls observed in pure Couette flow. A subclass of flows with $Re_{\tau, b}=0$ is investigated. Combined WMLES with modelling for these flows enables exploration of the $Re\to \infty$ limit, giving $\theta _c \to 45^\circ$ as $Re\to \infty$ .