Generating atmospheric turbulence using passive grids in an expansion test section of a wind tunnel

Vita, Giulio; Hemida, Hassan; Andrianne, Thomas; Baniotopoulos, Charalampos

doi:10.1016/j.jweia.2018.02.007

Cited by 39 publications

(37 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In general, for z/D > 0.2, I u~Iw , meaning that the turbulence is rather uniform and isotropic, close to grid turbulence and therefore easy to be reproduced in wind tunnels. This shows that it could be possible to use grid turbulence in wind tunnel testing for practitioners to design and test wind turbines in turbulent flows [40]. Such isotropic behaviour is not present at lower heights (z/D < 0.2), where the longitudinal component is significantly higher than the vertical one.…”

Section: Turbulence Intensitymentioning

confidence: 94%

On the Wind Energy Resource above High-Rise Buildings

et al. 2020

Self Cite

View full text Add to dashboard Cite

One of the main challenges of urban wind energy harvesting is the understanding of the flow characteristics where urban wind turbines are to be installed. Among viable locations within the urban environment, high-rise buildings are particularly promising due to the elevated height and relatively undisturbed wind conditions. Most research studies on high-rise buildings deal with the calculation of the wind loads in terms of surface pressure. In the present paper, flow pattern characteristics are investigated for a typical high-rise building in a variety of configurations and wind directions in wind tunnel tests. The aim is to improve the understanding of the wind energy resource in the built environment and give designers meaningful data on the positioning strategy of wind turbines to improve performance. In addition, the study provides suitable and realistic turbulence characteristics to be reproduced in physical or numerical simulations of urban wind turbines for several locations above the roof region of the building. The study showed that at a height of 10 m from the roof surface, the flow resembles atmospheric turbulence with an enhanced turbulence intensity above 10% combined with large length scales of about 200 m. Results also showed that high-rise buildings in clusters might provide a very suitable configuration for the installation of urban wind turbines, although there is a strong difference between the performance of a wind turbine installed at the centre of the roof and one installed on the leeward and windward corners or edges, depending on the wind direction.

show abstract

Section: Turbulence Intensitymentioning

confidence: 94%

On the Wind Energy Resource above High-Rise Buildings

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…The grid characteristics are the following; the width of the bars b = 5 cm, mesh size M = 35 cm (i.e., the distance between the centreline of the bars), and the downstream distance from the grid to the section where measurements were performed x = 5 m, see Figure 12. The x/M > 14 rate assures a homogeneous and isotropic turbulent flow [34], whose main characteristics are a turbulence intensity of I = 4.2% and an integral length L = 0.2 m.…”

Section: Wind Tunnel Experimentsmentioning

confidence: 99%

Single Output and Algebraic Modal Parameters Identification of a Wind Turbine Blade: Experimental Results

et al. 2021

View full text Add to dashboard Cite

This paper describes the evaluation of a single output, online, and time domain modal parameters identification technique based on differential algebra and operational calculus. In addition, an analysis of the frequency response function (FRF) of the system is conducted in a specific set up, emulating its nominal or operational conditions to determine the influence of the non-linearities over the dynamic behavior of the system in those particular magnitudes of deformations; thus, this influence is quantified by a numerical index. This methodology is applied to a wind turbine blade submitted to wind tunnel experiments. The natural frequencies and modal damping ratios of six bending modes associated with the blade are estimated using real-time velocity measurements from one single point of the blade. A comparison with the usual impact hammer modal testing is performed to evaluate and establish the proposed approach’s main contributions. The developed modal parameter identification algorithms are implemented to run into a standard personal computer (PC) where the data acquisition system’s measurements are conditioned and processed. The results show the performance and the fast parametric estimation of the proposed algebraic identification approach.

show abstract

“…A recent and synthetic review of these techniques can be found in the paper of Vita et al [2]. According to literature [2][3][4], turbulence grid generation is the most effective and reliable technique to produce turbulence in a wind tunnel. These grids can be classified in three categories: passive grids, active grids and fractal grids.…”

Section: Contextmentioning

confidence: 99%

Actuator line method applied to grid turbulence generation for large-Eddy simulations

Houtin-Mongrolle

Bricteux

Bénard

et al. 2020

Journal of Turbulence

View full text Add to dashboard Cite

The constant growth of computational resources allows performing Large-Eddy Simulation (LES) on realistic flow configurations. In this context, it is important to properly model boundary conditions and particularly inflow turbulence. This study addresses wind tunnel applications where the object under investigation is downstream of a turbulence grid. This grid aims at generating a highly turbulent sheared flow for further use in wind turbines applications. In this work, an original strategy based on the actuator line method (ALM) is proposed to emulate the grid and generate realistic flow structures downstream at a moderate computational cost. As a first validation test of the proposed method, the LES of a single square rod is performed and the results are compared to a scale resolving simulation. In a second phase, the method is applied to a passive grid with non-homogeneous spacing, which generates fully-developed turbulence. Results are compared to experimental data and other state-of-the-art turbulence injection strategies such as homogeneous isotropic turbulence injection and also scale resolving simulations.

show abstract

Generating atmospheric turbulence using passive grids in an expansion test section of a wind tunnel

Cited by 39 publications

References 55 publications

On the Wind Energy Resource above High-Rise Buildings

On the Wind Energy Resource above High-Rise Buildings

Single Output and Algebraic Modal Parameters Identification of a Wind Turbine Blade: Experimental Results

Actuator line method applied to grid turbulence generation for large-Eddy simulations

Contact Info

Product

Resources

About