Regularization modelling for large‐eddy simulation in wall‐bounded turbulence: An explicit filtering‐based approach

Chatterjee, Tanmoy; Peet, Yulia

doi:10.1002/fld.4508

Cited by 13 publications

(9 citation statements)

References 79 publications

(196 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Owing to the high resolution of the numerical method, spectral filtering is used to filter out high energy modes and prevent energy growth over time. The effectiveness of spectral filtering in capturing relevant flow statistics has been well established in the literature (e.g., Chatterjee & Peet, 2018). Other models for subgrid stresses such as Smagorinsky (SGS) can also be incorporated in Nek5000.…”

Section: Methodsmentioning

confidence: 99%

Large Eddy Simulation of three‐dimensional flow structures over wave‐generated ripples

Jin

Coco

Tinoco

et al. 2021

Earth Surf Processes Landf

View full text Add to dashboard Cite

We performed a three-dimensional high-resolution Large Eddy Simulation using a sinusoidal ripple-like bedform geometry with spacing and amplitude consistent with equilibrium conditions under the prescribed oscillatory forcing. The simulation results are validated qualitatively and quantitatively with previous laboratory experiments and numerical simulations. Our numerical simulations allow to analyze the presence of "ribs", strong flow rotational features in the spanwise direction developing perpendicular to the ripple crest. We show that ribs tend to appear on the upslope and crest of ripples and display a dominant spacing, ranging from 0.5λ to λ, during wave phases associated to flow acceleration. When the vortex is transported over the downstream ripple during the flow deceleration, ribs appear for the second time over the upslope of the downstream ripple, with the dominant spacing about 1/8 ripple wavelength. The presence of flow three-dimensionality corresponds to a large variability of the shear stress over ripples in the spanwise direction, which could ultimately favor the development of three-dimensional geometry. The threedimensional vortex dynamics are evaluated using the concept of vortex strength. Peak vortex strength is observed at the maximum free stream velocity, but the largest variation of the vortex strength and vortex size in the spanwise direction occurs prior to the flow reversal. The variability of the vortex structures might provide a favorable setting for the development of ribs and might relate to the spacing of ribs.

show abstract

Section: Methodsmentioning

confidence: 99%

Large Eddy Simulation of three‐dimensional flow structures over wave‐generated ripples

Jin

Coco

Tinoco

et al. 2021

Earth Surf Processes Landf

View full text Add to dashboard Cite

show abstract

“…Very close agreement is obtained between the two simulations, aside from the slight underprediction of TKE in the inner region, consistent with the grid resolution study of figure 24. The insensitivity of solutions to further grid refinement (in the outer and channel core regions) and the close agreement with DNS justifies the use of modal based explicit filtering (Fischer & Mullen 2001;Chatterjee & Peet 2018) and the choice of grid resolution.…”

Section: Appendix a Grid Sensitivity And Validation Studymentioning

confidence: 84%

The coupled dynamics of internal waves and hairpin vortices in stratified plane Poiseuille flow

2022

View full text Add to dashboard Cite

A simulation of stably stratified plane Poiseuille flow at a moderate Reynolds number ( $\textit {Re}_\tau = 550$ ) and Richardson number ( $\textit {Ri}_\tau = 480$ ) is presented. For the first time, the dynamics in the channel core are shown to be described as a series of internal waves that approximately obey a linear wave dispersion relationship. For a given streamwise wavenumber $k_x$ there are two internal wave solutions, a dominant low frequency mode and a weaker-amplitude high-frequency mode, respectively corresponding to ‘backward’ and ‘forward’ propagating internal waves relative to the mean flow. Analysis of linearised equations shows that the dominant low-frequency mode appears to arise due to a particularly sensitive response of the mean flow profiles to incoherent forcing. Instantaneous visualisations reveal that hairpin vortices dominate the outer region of the channel flow, neighbouring the buoyancy dominated channel core. These hairpins are fundamentally different from those observed in canonical unstratified boundary layer flows, as they arise via quasi-linear local processes far from the wall, governed by background shear. Outer region ejection events are common and can be induced by high amplitude waves. Ejected hairpins are transported into the channel core, in turn ‘ringing’ the prevailing strong buoyancy gradient and thus generating high-amplitude internal waves, high dissipation and wave breaking, induced by spanwise vortex stretching and baroclinic vorticity generation. Such spontaneous and sustained generation of quasi-linear internal waves by wall-bounded sheared turbulence may provide novel idealised solutions for, and insight into, large-scale turbulent mixing in a wide range of environmental and industrial flows.

show abstract

“…This is about 5 times more grid points than [16]. An explicit filteringbased regularization model [7] is used to ensure stabilty and is found to agree well with eddy-viscosity subgrid-scale models in turbulent channel flow [4]. The third-order temporal discretization scheme is used to step forward in time.…”

Section: Computational Setupmentioning

confidence: 99%

Turbulent Flow Over a Mounted Fence Confined in a Channel

Chan¹,

Skvortsov²,

Ooi³

2020

Australasian Fluid Mechanics Conference (AFMC)

View full text Add to dashboard Cite

Numerical simulation of a fence mounted in a channel is conducted at a friction Reynolds number of 180. The flow field is characterized by the blockage ratio, β, which is the ratio between the height of the fence to the height of the channel. Two different blockage ratios were simulated (β = 0.5 and 0.75) and the mean statistics, the separation and reattachment locations of the flow are analysed. It is observed that the streamwise structures in the flow are stretched as the flow accelerates through the gap between the fence and the channel walls. As expected, higher wall-normal turbulence intensities occur downstream of the fence for the case with higher blockage ratio due to the large favourable and adverse pressure gradient. The wall-normal velocity spectra of the flow downstream of the fence is constant at low frequencies and decay with a -19/3 and -23/3 slope for β = 0.5 and 0.75 respectively at high frequencies. The decay in the spectra for β = 0.75 occurs at a frequency about 4 times higher than for β = 0.5.

show abstract

Regularization modelling for large‐eddy simulation in wall‐bounded turbulence: An explicit filtering‐based approach

Cited by 13 publications

References 79 publications

Large Eddy Simulation of three‐dimensional flow structures over wave‐generated ripples

Large Eddy Simulation of three‐dimensional flow structures over wave‐generated ripples

The coupled dynamics of internal waves and hairpin vortices in stratified plane Poiseuille flow

Turbulent Flow Over a Mounted Fence Confined in a Channel

Contact Info

Product

Resources

About