Turbulent Fluxes and Coherent Structures in Marine Boundary Layers: Investigations by Large-Eddy Simulation

1999 ◽  
pp. 507-538 ◽  
Author(s):  
James C. McWilliams ◽  
Chin-Hoh Moeng ◽  
Peter P. Sullivan
Keyword(s):  
Large Eddy Simulation ◽  
Boundary Layers ◽  
Coherent Structures ◽  
Turbulent Fluxes ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Marine Boundary Layers

Transitions of cloud-topped marine boundary layers characterized by AIRS, MODIS, and a large eddy simulation model

2013 ◽  
Vol 118 (15) ◽  
pp. 8598-8611 ◽  
Author(s):  
Qing Yue ◽  
Brian H. Kahn ◽  
Heng Xiao ◽  
Mathias M. Schreier ◽  
Eric J. Fetzer ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Simulation Model ◽  
Boundary Layers ◽  
Large Eddy Simulation Model ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Marine Boundary Layers

scholarly journals Large-eddy simulation of subtropical cloud-topped boundary layers: 2. Cloud response to climate change

2017 ◽  
Vol 9 (1) ◽  
pp. 19-38 ◽  
Author(s):  
Zhihong Tan ◽  
Tapio Schneider ◽  
João Teixeira ◽  
Kyle G. Pressel
Keyword(s):  
Climate Change ◽  
Large Eddy Simulation ◽  
Boundary Layers ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Cloud Response

Large Eddy Simulation of Coherent Structures over Forest Canopy

2010 ◽  
pp. 143-149 ◽  
Author(s):  
K. Gavrilov ◽  
G. Accary ◽  
D. Morvan ◽  
D. Lyubimov ◽  
O. Bessonov ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Coherent Structures ◽  
Forest Canopy ◽  
Eddy Simulation ◽  
Large Eddy

Large-eddy Simulation of Accelerating Boundary Layers

2007 ◽  
pp. 137-143
Author(s):  
G. De Prisco ◽  
A. Keating ◽  
U. Piomelli ◽  
E. Balaras
Keyword(s):  
Large Eddy Simulation ◽  
Boundary Layers ◽  
Eddy Simulation ◽  
Large Eddy

Large-Eddy Simulation of Unsteady Surface Pressure Over a LP Turbine Blade Due to Interactions of Passing Wakes and Inflexional Boundary Layer

2005 ◽  
Author(s):  
S. Sarkar ◽  
Peter R. Voke
Keyword(s):  
Large Eddy Simulation ◽  
Turbine Blade ◽  
Coherent Structures ◽  
Pressure Fluctuations ◽  
Time Dependent ◽  
Suction Surface ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Grid Points ◽  
Lp Turbine

The unsteady pressure over the suction surface of a modern low-pressure (LP) turbine blade subjected to periodically passing wakes from a moving bar wake generator is described. The results presented are a part of detailed Large-Eddy Simulation (LES) following earlier experiments over the T106 profile for a Reynolds number of 1.6×105 (based on the chord and exit velocity) and the cascade pitch to chord ratio of 0.8. The present LES uses coupled simulations of cylinder for wake, providing four-dimensional inflow conditions for successor simulations of wake interactions with the blade. The three-dimensional, time-dependent, incompressible Navier-Stokes equations in fully covariant form are solved with 2.4×106 grid points for the cascade and 3.05×106 grid points for the cylinder using a symmetry-preserving finite difference scheme of second-order spatial and temporal accuracy. A separation bubble on the suction surface of the blade was found to form under the steady state condition. Pressure fluctuations of large amplitude appear on the suction surface as the wake passes over the separation region. Enhanced receptivity of perturbations associated with the inflexional velocity profile is the cause of instability and coherent vortices appear over the rear half of the suction surface by the rollup of shear layer via Kelvin-Helmholtz (K-H) mechanism. Once these vortices are formed, the steady-flow separation changes remarkably. These coherent structures embedded in the boundary amplify before breakdown while traveling downstream with a convective speed of about 37 percent of the local free-stream speed. The vortices play an important role in the generation of turbulence and thus to decide the transitional length, which becomes time-dependent. The source of the pressure fluctuations on the rear part of the suction surface is also identified as the formation of these coherent structures. When compared with experiments, it reveals that LES is worth pursuing as an understanding of the eddy motions and interactions is of vital importance for the problem.

Subgrid-scale modelling for the large-eddy simulation of high-Reynolds-number boundary layers

1997 ◽  
Vol 336 ◽  
pp. 151-182 ◽  
Author(s):  
BRANKO KOSOVIĆ
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Large Eddy Simulation ◽  
Boundary Layers ◽  
Nonlinear Model ◽  
High Reynolds Number ◽  
Subgrid Scale ◽  
Eddy Simulation ◽  
Large Eddy ◽  
High Reynolds

It has been recognized that the subgrid-scale (SGS) parameterization represents a critical component of a successful large-eddy simulation (LES). Commonly used linear SGS models produce erroneous mean velocity profiles in LES of high-Reynolds-number boundary layer flows. Although recently proposed approaches to solving this problem have resulted in significant improvements, questions about the true nature of the SGS problem in shear-driven high-Reynolds-number flows remain open.We argue that the SGS models must capture inertial transfer effects including backscatter of energy as well as its redistribution among the normal SGS stress components. These effects are the consequence of nonlinear interactions and anisotropy. In our modelling procedure we adopt a phenomenological approach whereby the SGS stresses are related to the resolved velocity gradients. We show that since the SGS stress tensor is not frame indifferent a more general nonlinear model can be applied to the SGS parameterization. We develop a nonlinear SGS model capable of reproducing the effects of SGS anisotropy characteristic for shear-driven boundary layers. The results obtained using the nonlinear model for the LES of a neutral shear-driven atmospheric boundary layer show a significant improvement in prediction of the non-dimensional shear and low-order statistics compared to the linear Smagorinsky-type models. These results also demonstrate a profound effect of the SGS model on the flow structures.

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