Imperial College London
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ProfessorSylvainLaizet

Faculty of Engineering, Department of Aeronautics

Professor in Computational Fluid Mechanics
 
 
 
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Contact

 

+44 (0)20 7594 5045s.laizet Website

 
 
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Location

 

339City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Frantz:2021:10.1016/j.compfluid.2021.104902,
author = {Frantz, R and Deskos, G and Laizet, S and Silvestrini, J},
doi = {10.1016/j.compfluid.2021.104902},
journal = {Computers and Fluids},
pages = {1--18},
title = {High-fidelity simulations of gravity currents using a high-order finite-difference spectral vanishing viscosity approach},
url = {http://dx.doi.org/10.1016/j.compfluid.2021.104902},
volume = {221},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - This numerical work investigates the potential of a high-order finite-difference spectralvanishing viscosity approach to simulate gravity currents at high Reynolds numbers.The method introduces targeted numerical dissipation at small scales through alteringthe discretisation of the second derivatives of the viscous terms in the incompressibleNavier-Stokes equations to mimic the spectral vanishing viscosity (SVV) operator, originally designed for the regularisation of spectral element method (SEM) solutions of pureadvection problems. Using a sixth-order accurate finite-difference scheme, the adoption ofthe SVV method is straightforward and comes with a negligible additional computationalcost. In order to assess the ability of this high-order finite-difference spectral vanishingviscosity approach, we performed large-eddy simulations (LES) of a gravity current ina channelised lock-exchange set-up with our SVV model and with the well-known explicit static and dynamic Smagorinsky sub-grid scale (SGS) models. The obtained dataare compared with a direct numerical simulation (DNS) based on more than 800 millionmesh nodes, and with experimental measurements. A framework for the energy budgetis introduced to investigate the behaviour of the gravity current. First, it is found thatthe DNS is in good agreement with the experimental data for the evolution of the frontlocation and velocity field as well as for the stirring and mixing inside the gravity current. Secondly, the LES performed with less than 0.4% of the total number of mesh nodescompared to the DNS, can reproduce the main features of the gravity currents, with theSVV model yielding slightly more accurate results. It is also found that the dynamicSmagorinsky model performs better than its static version. For the present study, thestatic and dynamic Smagorinsky models are 1.8 and 2.5 times more expensive than theSVV model, because the latter does not require the calculation of explicit SGS terms inthe Navier-Stokes equa
AU  - Frantz,R
AU  - Deskos,G
AU  - Laizet,S
AU  - Silvestrini,J
DO  - 10.1016/j.compfluid.2021.104902
EP  - 18
PY  - 2021///
SN  - 0045-7930
SP  - 1
TI  - High-fidelity simulations of gravity currents using a high-order finite-difference spectral vanishing viscosity approach
T2  - Computers and Fluids
UR  - http://dx.doi.org/10.1016/j.compfluid.2021.104902
UR  - https://www.sciencedirect.com/science/article/pii/S0045793021000682?via%3Dihub
UR  - http://hdl.handle.net/10044/1/86238
VL  - 221
ER  -
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