RANS Simulations of Neutral ABL and Wind
نویسندگان
چکیده
It is known that wind turbines actually operate in the lower part of the atmospheric 11 boundary layer (ABL), the modelling of this ABL flow is an important precondition for the 12 simulations of wind turbine wakes. So, the capabilities of various inlet boundary conditions with 13 related modelling methodologies in constructing equilibrium ABL are validated firstly through 14 cases of a neutral ABL over uniformly rough terrain, to ascertain there are no substantial changes in 15 the prescribed profiles throughout the whole computational domain. In this process, six commonly 16 used inflow turbulence profiles, including four uniform and two un-uniform ones, are considered 17 and investigated. Then, sensitivity studies on inflow profiles for predicting wind turbine wake 18 development are carried out. Through comparing with the Sexbierum field experimental data, in 19 terms of wake velocity and turbulence intensity along the cross-wind direction at several 20 downstream positions, this study finds out that the shape and magnitude of wake velocity and 21 turbulence profiles are significantly affected by different input turbulence profiles specified at the 22 inlet boundary. Possible reasons for this sensibility are discussed, and accordingly, some 23 suggestions are given to improve the wind turbine wake simulation. 24
منابع مشابه
Wind Energy Applications of Unified and Dynamic Turbulence Models
This study investigates linear and nonlinear dynamic LES and unified RANS-LES models obtained by stochastic analysis regarding the simulation of the atmospheric boundary layer. The advantages of dynamic LES methods are their accuracy, the ability to account for anisotropy and backscatter, and their computational stability. The advantage of unified RANS-LES models is their ability to provide res...
متن کاملRevealing the impact of changing land use of the annual spatiotemporal boundary layer height (Kermanshah Case Study)
Introduction Atmospheric boundary layer (ABL), is the lowest part of the atmosphere. Its behavior is directly influenced by its contact with earth surface. On earth it usually responds to changes in surface radiative forcing in an hour or less. In this layer physical quantities such as flow velocity, temperature, moisture, etc., display rapid fluctuations (turbulence) and vertical mixing is st...
متن کاملLarge-eddy simulation of neutral atmospheric boundary layer flow over heterogeneous surfaces: Blending height and effective surface roughness
[1] A new generation large-eddy simulation (LES), based on a Lagrangian scaledependent dynamic subgrid model, is applied to neutral atmospheric flow over heterogeneous land surfaces. This LES is faithful to the physics of the interaction of the lower atmosphere and the land surface based on classical validation tests of the simulated mean wind profile and the atmospheric turbulence. Simulations...
متن کاملSimplified Wind Flow Model for the Estimation of Aerodynamic Effects on Small Structures
The reliable measurement of pressures on low-rise buildings in the atmospheric boundary layer (ABL) flow remains a challenge, as has been shown by the large discrepancies among results obtained in different wind tunnel facilities or even in the samewind tunnel. Twomajor causes of the discrepancies are the difficulty of simulating large-scale, low-frequency turbulent fluctuations uniformly acros...
متن کاملDependence of offshore wind turbine fatigue loads on atmospheric stratification
The stratification of the atmospheric boundary layer (ABL) is classified in terms of the M-O length and subsequently used to determine the relationship between ABL stability and the fatigue loads of a wind turbine located inside an offshore wind farm. Recorded equivalent fatigue loads, representing blade-bending and tower bottom bending, are combined with the operational statistics from the ins...
متن کامل