A wind tunnel study of the aerodynamic characteristics of a scaled, aeroelastic, model tree

Hao, Yanfeng; Kopp, Gregory A.; Wu, Chieh-Hsun; Gillmeier, Stefanie

doi:10.1016/j.jweia.2019.104088

Cited by 11 publications

(4 citation statements)

References 32 publications

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“…For instance, as discussed in § 2.3, the slenderness ratio and Cauchy number both play a role in the ultimate tree response, and prior work has also shown that the detailed tree and crown geometry can have a substantial effect on the tree dynamics in response to wind. Examples of geometric features that impact the tree response include branch size and insertion angle (Sellier & Fourcaud, 2009), branching structure (Hao, Kopp, Wu, & Gillmeier, 2020;James, 2003;Moore & Maguire, 2004) and trunk taper (Gardiner, 1992;Morgan & Cannell, 1987). Tree response also exhibits seasonal variation.…”

Section: Application To Anemometry and Calibration Reference Point Considerationsmentioning

confidence: 99%

Wind speed inference from environmental flow–structure interactions. Part 2. Leveraging unsteady kinematics

Cardona

Dabiri

2022

Flow

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This work explores the relationship between wind speed and time-dependent structural motion response as a means of leveraging the rich information visible in flow–structure interactions for anemometry. We build on recent work by Cardona, Bouman and Dabiri (Flow, vol. 1, 2021, E4), which presented an approach using mean structural bending. Here, we present the amplitude of the dynamic structural sway as an alternative signal that can be used when mean bending is small or inconvenient to measure. A force balance relating the instantaneous loading and instantaneous deflection yields a relationship between the incident wind speed and the amplitude of structural sway. This physical model is applied to two field datasets comprising 13 trees of 4 different species exposed to ambient wind conditions. Model generalization to the diverse test structures is achieved through normalization with respect to a reference condition. The model agrees well with experimental measurements of the local wind speed, suggesting that tree sway amplitude can be used as an indirect measurement of mean wind speed, and is applicable to a broad variety of diverse trees.

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Section: Application To Anemometry and Calibration Reference Point Considerationsmentioning

confidence: 99%

Wind speed inference from environmental flow–structure interactions. Part 2. Leveraging unsteady kinematics

Cardona

Dabiri

2022

Flow

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“…However, these studies may not meet similarity criteria because of mismatches between the stem, the branch and leaf sizes. This makes it challenging to transfer the measured results to full-scale for a large wind speed range (Hao et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Drag relationships for full-grown Scots pine trees

2022

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The wind force acting on full-grown pine trees as they free fall was calculated based on comparison of the results of the field experiment and numerical simulation (Borisevich and Vikhrenko 2018). A number of improvements were proposed in order to increase the accuracy of the method. Field experiments of the free fall of five pine trees previously cut were carried out. Then, computer simulations of their motion assuming the linear dependence of drag force on air velocity were performed. Comparisons of the data of the field experiments and computer simulations showed that the linear dependence with a constant scaling parameter gives a good approximation of the drag force at a wide range of air velocity values. Error analysis was carried out to assess the quality of the numerical model. At all times during the movement, the deviations in the center mass positions observed in the field experiment and obtained in the numerical experiment do not exceed the diameter of the tree stem. The scaling parameter for five full-grown Scots pines (Pinus sylvestris L.) growing in stands ranged between 25.5 to 90.0 kg/s.

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“…Furthermore, in a wind tunnel, it is also possible to study (i) the dispersion processes of pollutants, dust and pollen, and (ii) the evolution of parameters such as the Reynolds number in the presence of obstacles such as a group of trees and/or buildings. 3,4 Based on the shape, wind tunnels are classified into two main types: open-circuit wind tunnel and closed-circuit wind tunnel. In an open-circuit tunnel, the air flow follows a straight path from the entrance through a contraction zone to the test section, followed by a diffuser, a fan section, and an outlet.…”

Section: Introductionmentioning

confidence: 99%

Air flow quality analysis of an open-circuit boundary layer wind tunnel and comparison with a closed-circuit wind tunnel

et al. 2020

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The wide use of wind tunnels, as a tool to measure the flow properties and the flow effects on different structures/ecosystems, makes it necessary to guarantee the correct functioning of the facility and to carry out a continuous monitoring. The aim of this work is (i) to check the homogeneity and quality of the air flow in an open-circuit boundary layer wind tunnel, (ii) to provide data and ideas that could help other researchers to improve similar tunnels, and (iii) to compare some of the results with the behavior of a classic closed-circuit wind tunnel. Experiments are carried out working with a constant reference velocity, using a hot cross wire anemometry system to obtain high resolution measurements, in the entrance and test sections for different longitudinal and cross planes. The results concern the characteristics of the mean and turbulent flow. In this manuscript, we report the analysis of the turbulence production, the Reynolds stresses, the vertical velocity skewness, the vorticity, and the spectral properties, and a quadrant decomposition is also performed. Finally, comparing the results with respect to a closed-circuit wind tunnel, it is shown that the turbulence intensity is generally higher and the mean flow is more homogeneous in the present open-circuit wind tunnel. Moreover, the Reynolds number is similar in both tunnels, which indicates that both tunnels are mechanically similar.

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A wind tunnel study of the aerodynamic characteristics of a scaled, aeroelastic, model tree

Cited by 11 publications

References 32 publications

Wind speed inference from environmental flow–structure interactions. Part 2. Leveraging unsteady kinematics

Wind speed inference from environmental flow–structure interactions. Part 2. Leveraging unsteady kinematics

Drag relationships for full-grown Scots pine trees

Air flow quality analysis of an open-circuit boundary layer wind tunnel and comparison with a closed-circuit wind tunnel

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