Influences of Atmospheric Boundary Layer Turbulence Structure on the Space-time Variability in Wind Turbine Blade and Shaft Loadings

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

Prediction of laminar, transitional and turbulent flow regimes, based on three-equation k-ω turbulence model

2008 ◽  
Vol 112 (1134) ◽  
pp. 469-476 ◽  
Author(s):  
R. Taghavi-Zenouz ◽  
M. Salari ◽  
M. Etemadi
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Wind Turbine ◽  
Flat Plate ◽  
Turbine Blade ◽  
Wind Turbine Blade ◽  
Freestream Turbulence ◽  
Boundary Layer Flows ◽  
Laminar Separation ◽  
Transitional Boundary Layer

Abstract A recently developed transitional model for boundary-layer flows has been examined on a flat plate and the well-known S809 wind turbine blade. Proposed numerical model tries to simulate streamwise fluctuations, induced by freestream turbulence, in pre-transitional boundary-layer flows by introducing an additional transport equation for laminar kinetic energy term. This new approach can be used for modeling of transitional flows which are exposed to both the freestream turbulence intensity and streamwise pressure gradient, which are known as the most dominant factors in occurrence of transition. Computational method of this model is based on the solution of the Reynolds averaged Navier-Stokes (RANS) equations and the eddy-viscosity concept. The model includes three transport equations of laminar kinetic energy, turbulent kinetic energy and dissipation rate frequency. The present model is capable of predicting either natural or bypass transitional mechanisms, which may occur in attached boundary-layer flows. In addition, the model can simulate transition in the separated free shear layers and the subsequent turbulent re-attachment to form a laminar separation bubble. Flat plate was exposed to different freestream turbulence intensities and streamwise pressure gradients. Wind turbine blade was examined under two different Reynolds numbers, with one of them suitable for the occurrence of laminar separation bubbles on its surfaces. To evaluate the performance of this new model in resolving transitional boundary-layer flows, final results have been compared to those obtained through application of conventional turbulence models. Comparison of final results for the flat plate and the S809 aerofoil with available experimental data show very close agreements.

J056032 LDV Measurement of Boundary Layer on Wind Turbine Blade

2013 ◽  
Vol 2013 (0) ◽  
pp. _J056032-1-_J056032-5 ◽  
Author(s):  
Yasunari KAMADA ◽  
Tinnapob PHENGPOM ◽  
Takao MAEDA ◽  
Junsuke MURATA ◽  
Yosuke KAGISAKI ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Wind Turbine Blade ◽  
Ldv Measurement

scholarly journals The laminar boundary layer on a rotating wind turbine blade

2010 ◽  
Vol 2 (2) ◽  
pp. 40-49
Author(s):  
DUMITRESCU Horia ◽  
◽  
CARDOŞ Vladimir ◽  
DUMITRACHE Alexandru ◽  
FRUNZULICĂ Florin
Keyword(s):  
Boundary Layer ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Laminar Boundary Layer ◽  
Wind Turbine Blade

scholarly journals Investigation of Laminar-Turbulent Transition on a Rotating Wind Turbine Blade of Multi Megawatt Class with Thermography and a Microphone Array

2019 ◽  
Author(s):  
Torben Reichstein ◽  
Alois Peter Schaffarczyk ◽  
Christoph Dollinger ◽  
Nicolas Balaresque ◽  
Erich Schuelein ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Microphone Array ◽  
Turbine Blades ◽  
Suction Side ◽  
Wind Turbine Blade ◽  
Flow Transition ◽  
Turbulent Transition ◽  
Laminar Turbulent Transition

Knowledge about laminar-turbulent transition on operating multi-megawatt wind turbine blades needs sophisticated equipment like hot-films or microphone arrays. Contrarily thermographic pictures can easily be taken from the ground and temperature differences indicate different states of the boundary layer. The accuracy however, still is an open question, so that an aerodynamic glove known from experimental research on aero-planes was used to classify the boundary-layer state of a 2 megawatt wind turbine blade operating in the orthern part of Schleswig-Holstein, Germany. State-of-the-art equipment for measurering static surface pressure was used for monitoring the lift distribution. To distinguish laminar and turbulent parts of the boundary layer (suction side only) 48 microphones were applied together with ground-based thermographic cameras from two teams. Additionally, an optical camera mounted on the hub was used to survey vibrations. During start-up (from 0 to 9 rpm) extended, but irregularly shaped regions of a laminar boundary layer were observed which had the same extension measured both with microphones and Thermography. When an approximately constant rotor rotation (9 rpm corresponding to approximately 6 m/s wind-speed) was achieved, a flow transition was visible at the expected position of 40 % chord length on the rotor blade, which was fouled with dense turbulent wedges and an almost complete turbulent state on the glove was detected. In all observations, quantitative determination of the flow transition positions from thermography and microphones agree well within their accuracy.

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