Space-Time Loadings on Wind Turbine Blades Driven by Atmospheric Boundary Layer Turbulence

2011 ◽  
Author(s):  
Adam Lavely ◽  
Ganesh Vijayakumar ◽  
Michael Kinzel ◽  
James Brasseur ◽  
Eric Paterson
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Space Time ◽  
Wind Turbine Blades ◽  
Boundary Layer Turbulence

RESEARCH OF THE ROTATIONAL EFFECTS ON THE BOUNDARY LAYER OF WIND TURBINE BLADES

2009 ◽  
Vol 23 (03) ◽  
pp. 505-508 ◽  
Author(s):  
RUI YANG ◽  
REN-NIAN LI ◽  
WEI HAN ◽  
DE-SHUN LI
Keyword(s):  
Boundary Layer ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Aerodynamic Coefficients ◽  
Wind Turbine Blades ◽  
Pressure Distributions ◽  
Rotating Blade ◽  
Show Evidence ◽  
Layer Flow ◽  
Nrel Phase Vi

The flow field past the rotating blade of a horizontal axial wind turbine has been modeled with a full 3–D steady–RANS approach. Flow computations have been performed using the commercial finite–volume solver Fluent. The NREL phase VI wind turbine blade sections from the 3–D rotating geometry were chosen and the corresponding 2–D flow computations have been carried out for comparison with different angles of attack and in stalled conditions. The simulation results are analyzed. The main features of the boundary layer flow are described, for both the rotating blade and the corresponding 2–D profiles. Computed pressure distributions and aerodynamic coefficients show evidence of less lift losses after separation in the 3–D rotating case, mostly for the inward sections of the blade and the highest angles of attack, which is in agreement with the literature.

scholarly journals CFD–RANS analysis of the rotational effects on the boundary layer of wind turbine blades

2007 ◽  
Vol 75 ◽  
pp. 012031 ◽  
Author(s):  
Carlo E Carcangiu ◽  
Jens N Sørensen ◽  
Francesco Cambuli ◽  
Natalino Mandas
Keyword(s):  
Boundary Layer ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Rans Analysis

scholarly journals Towards reduced order modelling for predicting the dynamics of coherent vorticity structures within wind turbine wakes

2017 ◽  
Vol 375 (2091) ◽  
pp. 20160108 ◽  
Author(s):  
M. Debnath ◽  
C. Santoni ◽  
S. Leonardi ◽  
G. V. Iungo
Keyword(s):  
Boundary Layer ◽  
Velocity Field ◽  
Atmospheric Boundary Layer ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Dynamic Mode ◽  
Decomposition Techniques ◽  
Modal Decomposition ◽  
Tip Vortices ◽  
Reduced Order

The dynamics of the velocity field resulting from the interaction between the atmospheric boundary layer and a wind turbine array can affect significantly the performance of a wind power plant and the durability of wind turbines. In this work, dynamics in wind turbine wakes and instabilities of helicoidal tip vortices are detected and characterized through modal decomposition techniques. The dataset under examination consists of snapshots of the velocity field obtained from large-eddy simulations (LES) of an isolated wind turbine, for which aerodynamic forcing exerted by the turbine blades on the atmospheric boundary layer is mimicked through the actuator line model. Particular attention is paid to the interaction between the downstream evolution of the helicoidal tip vortices and the alternate vortex shedding from the turbine tower. The LES dataset is interrogated through different modal decomposition techniques, such as proper orthogonal decomposition and dynamic mode decomposition. The dominant wake dynamics are selected for the formulation of a reduced order model, which consists in a linear time-marching algorithm where temporal evolution of flow dynamics is obtained from the previous temporal realization multiplied by a time-invariant operator. This article is part of the themed issue ‘Wind energy in complex terrains’.

Application of Tubercles in Wind Turbine Blades: A Review

2017 ◽  
Vol 867 ◽  
pp. 254-260 ◽  
Author(s):  
Vivek V. Kumar ◽  
Dilip A. Shah
Keyword(s):  
Boundary Layer ◽  
Wind Turbine ◽  
Fossil Fuels ◽  
Turbine Blades ◽  
Leading Edge ◽  
Electrical Energy ◽  
Humpback Whale ◽  
Wind Turbine Blades ◽  
Horizontal Axis Wind Turbine ◽  
Turbulent Fluid Flow

Due to the rapid depletion of conventional energy resources like fossil fuels and their harmful effects on the environment, there is an urgent need to seek alternative and sustainable energy sources. Wind energy is considered as one of the efficient source of energy which can be converted to useful form of energy like electrical energy. Though the field of wind engineering has developed in the recent era there is still scope for improvement in the effective utilization of energy. Energy efficiency in wind turbine is largely determined by the aerodynamics of the turbine blades and the characteristics of the turbulent fluid flow. The objective of this paper is to have a review on the improvement of Horizontal Axis Wind Turbine (HAWT) blade design by incorporating biomimetics into blades. Biomimetics is the field of science in which we adapt designs from nature to solve modern problems. The morphology of the wing-like flipper of the humpback whale (Megaptera novaeangliae) has potential for aerodynamic applications. Instead of straight leading edges like that of conventional hydrofoils, the humpback whale flipper has a number of sinusoidal rounded bumps, called tubercles arranged periodically along the leading edge. The presence of tubercles modifies the flow over the blade surface, creating vortices between the tubercles. These vortices interact with the flow over the tubercle and accelerate that flow, helping to maintain a partially attached boundary layer. This aerodynamic effect can delay stall to higher angles of attack, increase lift and reduce drag compared to the post-stall condition of conventional airfoils. The modified airfoil is characterized by a superior lift/drag ratio (L/D ratio) due to greater boundary layer attachment from vortices energizing the boundary layer.

Three-dimensional boundary layer on wind turbine blades

PAMM ◽  
2004 ◽  
Vol 4 (1) ◽  
pp. 432-433 ◽  
Author(s):  
Horia Dumitrescu ◽  
Vladimir Cardos
Keyword(s):  
Boundary Layer ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Wind Turbine Blades ◽  
Dimensional Boundary

scholarly journals Measurements of High-Frequency Atmospheric Turbulence and Its Impact on the Boundary Layer of Wind Turbine Blades

2018 ◽  
Vol 8 (9) ◽  
pp. 1417 ◽  
Author(s):  
Alois Schaffarczyk ◽  
Andreas Jeromin
Keyword(s):  
Boundary Layer ◽  
Wind Turbine ◽  
Atmospheric Turbulence ◽  
Turbine Blades ◽  
Stable Stratification ◽  
Offshore Wind ◽  
Wind Turbine Blades ◽  
Gaussian Distributions ◽  
Neutral Boundary Layer ◽  
The Stability

To gain insight into the differences between onshore and offshore atmospheric turbulence, pressure fluctuations were measured for offshore wind under different environmental conditions. A durable piezo-electric sensor was used to sample turbulent pressure data at 50 kHz. Offshore measurements were performed at a height of 100 m on Germany’s FINO3 offshore platform in the German Bight together with additional meteorological data provided by Deutscher Wetterdienst (DWD). The statistical evaluation revealed that the stability state in the atmospheric boundary does not seem to depend on simple properties like the Reynolds number, wind speed, wind direction, or turbulence level. Therefore, we used higher statistical properties (described by so-called shape factors) to relate them to the stability state. Data was classified to be either within an unstable, neutral, or stable stratification. We found that, in case of stable stratification, the shape factor was mostly close to zero, indicating that a thermally stable environment produces closer-to Gaussian distributions. Non-Gaussian distributions were found in unstable and neutral boundary layer states, and an occurrence probability was estimated. Possible impacts on the laminar-turbulent transition on the blade are discussed with the application of so-called laminar airfoils on wind turbine blades.

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