Publication

The effect of atmospheric stability on wind-turbine wakes: A large-eddy simulation study

Fernando Porté Agel, Mahdi Abkar
2014
Conference Papers

Abstract

In this study, large-eddy simulation is used to investigate the influence of atmospheric stability on wind-turbine wakes. In the simulations, tuning-free Lagrangian scale-dependent dynamic models are used to model the subgrid-scale turbulent fluxes, while the turbine-induced forces are parameterized with an actuator-disk model. Emphasis is placed on studying the structure and characteristics of turbine wake in the cases where the incident flow to the turbine has the same mean velocity at the hub height but different thermal stability condition. The simulation results show that the atmospheric stability has a significant effect on the spatial distribution of the mean velocity deficit and turbulent fluxes in the wake region. In particular, in the convective boundary layer, the wake recovers faster, and the locations of the maximum turbulence intensity and turbulent stresses are closer to the turbine compared with the neutral and stable cases.

Official source

https://infoscience.epfl.ch/entities/publication/1ad97291-c3b2-40c2-a59a-09bd8a91368d

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Fernando Porté Agel, Mahdi Abkar
2014
Conference Papers

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/1ad97291-c3b2-40c2-a59a-09bd8a91368d

About this result

Related concepts (20)

Large eddy simulation

Large eddy simulation (LES) is a mathematical model for turbulence used in computational fluid dynamics. It was initially proposed in 1963 by Joseph Smagorinsky to simulate atmospheric air currents, and first explored by Deardorff (1970). LES is currently applied in a wide variety of engineering applications, including combustion, acoustics, and simulations of the atmospheric boundary layer. The simulation of turbulent flows by numerically solving the Navier–Stokes equations requires resolving a very wide range of time and length scales, all of which affect the flow field.

Wind-turbine aerodynamics

The primary application of wind turbines is to generate energy using the wind. Hence, the aerodynamics is a very important aspect of wind turbines. Like most machines, wind turbines come in many different types, all of them based on different energy extraction concepts. Though the details of the aerodynamics depend very much on the topology, some fundamental concepts apply to all turbines. Every topology has a maximum power for a given flow, and some topologies are better than others.

Turbulence

In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between those layers. Turbulence is commonly observed in everyday phenomena such as surf, fast flowing rivers, billowing storm clouds, or smoke from a chimney, and most fluid flows occurring in nature or created in engineering applications are turbulent.

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