Resolved-scale turbulence in the atmospheric surface layer from a large eddy simulation

1995 ◽  
Vol 75 (3) ◽  
pp. 301-314 ◽  
Author(s):  
Xiaoming Cai ◽  
D. G. Steyn ◽  
I. S. Gartshore
Keyword(s):  
Surface Layer ◽  
Large Eddy Simulation ◽  
Atmospheric Surface Layer ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Scale Turbulence

Structure of subfilter-scale fluxes in the atmospheric surface layer with application to large-eddy simulation modelling

2003 ◽  
Vol 482 ◽  
pp. 101-139 ◽  
Author(s):  
PETER P. SULLIVAN ◽  
THOMAS W. HORST ◽  
DONALD H. LENSCHOW ◽  
CHIN-HOH MOENG ◽  
JEFFREY C. WEIL
Keyword(s):  
Surface Layer ◽  
Large Eddy Simulation ◽  
Atmospheric Surface Layer ◽  
Simulation Modelling ◽  
Eddy Simulation ◽  
Large Eddy

scholarly journals Vertically nested LES for high-resolution simulation of the surface layer in PALM (version 5.0)

2019 ◽  
Vol 12 (6) ◽  
pp. 2523-2538 ◽  
Author(s):  
Sadiq Huq ◽  
Frederik De Roo ◽  
Siegfried Raasch ◽  
Matthias Mauder
Keyword(s):  
Boundary Layer ◽  
Surface Layer ◽  
High Resolution ◽  
Large Eddy Simulation ◽  
Grid Resolution ◽  
Computational Power ◽  
Fine Grid ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Nesting Algorithm

Abstract. Large-eddy simulation (LES) has become a well-established tool in the atmospheric boundary layer research community to study turbulence. It allows three-dimensional realizations of the turbulent fields, which large-scale models and most experimental studies cannot yield. To resolve the largest eddies in the mixed layer, a moderate grid resolution in the range of 10 to 100 m is often sufficient, and these simulations can be run on a computing cluster with a few hundred processors or even on a workstation for simple configurations. The desired resolution is usually limited by the computational resources. However, to compare with tower measurements of turbulence and exchange fluxes in the surface layer, a much higher resolution is required. In spite of the growth in computational power, a high-resolution LES of the surface layer is often not feasible: to fully resolve the energy-containing eddies near the surface, a grid spacing of O(1 m) is required. One way to tackle this problem is to employ a vertical grid nesting technique, in which the surface is simulated at the necessary fine grid resolution, and it is coupled with a standard, coarse, LES that resolves the turbulence in the whole boundary layer. We modified the LES model PALM (Parallelized Large-eddy simulation Model) and implemented a two-way nesting technique, with coupling in both directions between the coarse and the fine grid. The coupling algorithm has to ensure correct boundary conditions for the fine grid. Our nesting algorithm is realized by modifying the standard third-order Runge–Kutta time stepping to allow communication of data between the two grids. The two grids are concurrently advanced in time while ensuring that the sum of resolved and sub-grid-scale kinetic energy is conserved. We design a validation test and show that the temporally averaged profiles from the fine grid agree well compared to the reference simulation with high resolution in the entire domain. The overall performance and scalability of the nesting algorithm is found to be satisfactory. Our nesting results in more than 80 % savings in computational power for 5 times higher resolution in each direction in the surface layer.

Physics and modeling of small scale turbulence for large eddy simulation

1999 ◽  
pp. 221-231
Author(s):  
C. Meneveau ◽  
J. O’Neil ◽  
F. Porte-Agel ◽  
S. Cerutti ◽  
M. B. Parlange
Keyword(s):  
Large Eddy Simulation ◽  
Small Scale ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Scale Turbulence

Large-Eddy Simulation of Transition in a Separation Bubble

2005 ◽  
Author(s):  
Stephen K. Roberts ◽  
Metin I. Yaras
Keyword(s):  
Large Eddy Simulation ◽  
Separation Bubble ◽  
Suction Side ◽  
Transition Process ◽  
Numerical Dissipation ◽  
Free Stream Turbulence ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Scale Turbulence ◽  
Turbine Airfoils

In this paper, large-eddy simulation of the transition process in a separation bubble is compared to experimental results. The measurements and simulations are conducted under low free-stream turbulence conditions over a flat plate with a streamwise pressure distribution typical of those encountered on the suction side of turbine airfoils. The computational grid is sufficiently refined that the effects of sub-grid scale turbulence are adequately represented by the numerical dissipation of the computational algorithm. The large-eddy simulations are shown to accurately capture the transition process in the separated shear layer. The results of these simulations are used to gain further insight into the breakdown mechanisms in transitioning separation bubbles.

Validation of Large-Eddy Simulation Methods for Gravity Wave Breaking

2015 ◽  
Vol 72 (9) ◽  
pp. 3537-3562 ◽  
Author(s):  
Sebastian Remmler ◽  
Stefan Hickel ◽  
Mark D. Fruman ◽  
Ulrich Achatz
Keyword(s):  
Large Eddy Simulation ◽  
Gravity Wave ◽  
Wave Breaking ◽  
Three Dimensional ◽  
Small Scale ◽  
Turbulence Parameterization ◽  
Eddy Simulation ◽  
Numerical Studies ◽  
Large Eddy ◽  
Scale Turbulence

Abstract To reduce the computational costs of numerical studies of gravity wave breaking in the atmosphere, the grid resolution has to be reduced as much as possible. Insufficient resolution of small-scale turbulence demands a proper turbulence parameterization in the framework of a large-eddy simulation (LES). The authors validate three different LES methods—the adaptive local deconvolution method (ALDM), the dynamic Smagorinsky method (DSM), and a naïve central discretization without turbulence parameterization (CDS4)—for three different cases of the breaking of well-defined monochromatic gravity waves. For ALDM, a modification of the numerical flux functions is developed that significantly improves the simulation results in the case of a temporarily very smooth velocity field. The test cases include an unstable and a stable inertia–gravity wave as well as an unstable high-frequency gravity wave. All simulations are carried out both in three-dimensional domains and in two-dimensional domains in which the velocity and vorticity fields are three-dimensional (so-called 2.5D simulations). The results obtained with ALDM and DSM are generally in good agreement with the reference direct numerical simulations as long as the resolution in the direction of the wave vector is sufficiently high. The resolution in the other directions has a weaker influence on the results. The simulations without turbulence parameterization are only successful if the resolution is high and the level of turbulence is comparatively low.

Sign in / Sign up

Export Citation Format

Share Document