Micro-scale model comparison (benchmark) at the moderately complex forested site Ryningsnäs

Stefan Ivanell*, Johan Arnqvist, Matias Avila, Dalibor Cavar, Roberto Aurelio Chavez-Arroyo, Hugo Olivares-Espinosa, Carlos Peralta, Jamal Adib, Björn Witha

*Corresponding author for this work

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Abstract

This article describes a study in which modellers were challenged to compute the wind field at a forested site with moderately complex topography. The task was to model the wind field in stationary conditions with neutral stratification by using the wind velocity measured at 100 m at a metmast as the only reference. Detailed maps of terrain elevation and forest densities were provided as the only inputs, derived from airborne laser scans (ALSs) with a resolution of 10 m × 10 m covering an area of 50 km × 50 km, that closely match the actual forest and elevation of the site. The participants were free to apply their best practices for the simulation to decide the size of the domain, the value of the geostrophic wind, and every other modelling parameter. The comparison of the results with the measurements is shown for the vertical profiles of wind speed, shear, wind direction, and turbulent kinetic energy. The ALS-based data resulted in reasonable agreement of the wind profile and turbulence magnitude. The best performance was found to be that of large-eddy simulations using a very large domain. For the Reynolds-averaged Navier–Stokes type of models, the constants in the turbulence closure were shown to have a great influence on the yielded turbulence level, but were of much less importance for the wind speed profile. Of the variety of closure constants used by the participating modellers, the closure constants from Sogachev and Panferov (2006) proved to agree best with the measurements. Particularly the use of Cμ≈0.03 in the kε model obtained better agreement with turbulence level measurements. All except two participating models used the full detailed ground and forest information to model the forest, which is considered significant progress compared to previous conventional approaches. Overall, the article gives an overview of how well different types of models are able to capture the flow physics at a moderately complex forested site.

Original languageEnglish
JournalWind Energy Science
Volume3
Issue number2
Pages (from-to)929-946
ISSN2366-7443
DOIs
Publication statusPublished - 2018

Keywords

  • Renewable energy sources
  • TJ807-830

Cite this

Ivanell, S., Arnqvist, J., Avila, M., Cavar, D., Chavez-Arroyo, R. A., Olivares-Espinosa, H., ... Witha, B. (2018). Micro-scale model comparison (benchmark) at the moderately complex forested site Ryningsnäs. Wind Energy Science, 3(2), 929-946. https://doi.org/10.5194/wes-3-929-2018
Ivanell, Stefan ; Arnqvist, Johan ; Avila, Matias ; Cavar, Dalibor ; Chavez-Arroyo, Roberto Aurelio ; Olivares-Espinosa, Hugo ; Peralta, Carlos ; Adib, Jamal ; Witha, Björn. / Micro-scale model comparison (benchmark) at the moderately complex forested site Ryningsnäs. In: Wind Energy Science. 2018 ; Vol. 3, No. 2. pp. 929-946.
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abstract = "This article describes a study in which modellers were challenged to compute the wind field at a forested site with moderately complex topography. The task was to model the wind field in stationary conditions with neutral stratification by using the wind velocity measured at 100 m at a metmast as the only reference. Detailed maps of terrain elevation and forest densities were provided as the only inputs, derived from airborne laser scans (ALSs) with a resolution of 10 m × 10 m covering an area of 50 km × 50 km, that closely match the actual forest and elevation of the site. The participants were free to apply their best practices for the simulation to decide the size of the domain, the value of the geostrophic wind, and every other modelling parameter. The comparison of the results with the measurements is shown for the vertical profiles of wind speed, shear, wind direction, and turbulent kinetic energy. The ALS-based data resulted in reasonable agreement of the wind profile and turbulence magnitude. The best performance was found to be that of large-eddy simulations using a very large domain. For the Reynolds-averaged Navier–Stokes type of models, the constants in the turbulence closure were shown to have a great influence on the yielded turbulence level, but were of much less importance for the wind speed profile. Of the variety of closure constants used by the participating modellers, the closure constants from Sogachev and Panferov (2006) proved to agree best with the measurements. Particularly the use of Cμ≈0.03 in the k–ε model obtained better agreement with turbulence level measurements. All except two participating models used the full detailed ground and forest information to model the forest, which is considered significant progress compared to previous conventional approaches. Overall, the article gives an overview of how well different types of models are able to capture the flow physics at a moderately complex forested site.",
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author = "Stefan Ivanell and Johan Arnqvist and Matias Avila and Dalibor Cavar and Chavez-Arroyo, {Roberto Aurelio} and Hugo Olivares-Espinosa and Carlos Peralta and Jamal Adib and Bj{\"o}rn Witha",
year = "2018",
doi = "10.5194/wes-3-929-2018",
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Ivanell, S, Arnqvist, J, Avila, M, Cavar, D, Chavez-Arroyo, RA, Olivares-Espinosa, H, Peralta, C, Adib, J & Witha, B 2018, 'Micro-scale model comparison (benchmark) at the moderately complex forested site Ryningsnäs', Wind Energy Science, vol. 3, no. 2, pp. 929-946. https://doi.org/10.5194/wes-3-929-2018

Micro-scale model comparison (benchmark) at the moderately complex forested site Ryningsnäs. / Ivanell, Stefan; Arnqvist, Johan; Avila, Matias; Cavar, Dalibor; Chavez-Arroyo, Roberto Aurelio; Olivares-Espinosa, Hugo; Peralta, Carlos; Adib, Jamal; Witha, Björn.

In: Wind Energy Science, Vol. 3, No. 2, 2018, p. 929-946.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Micro-scale model comparison (benchmark) at the moderately complex forested site Ryningsnäs

AU - Ivanell, Stefan

AU - Arnqvist, Johan

AU - Avila, Matias

AU - Cavar, Dalibor

AU - Chavez-Arroyo, Roberto Aurelio

AU - Olivares-Espinosa, Hugo

AU - Peralta, Carlos

AU - Adib, Jamal

AU - Witha, Björn

PY - 2018

Y1 - 2018

N2 - This article describes a study in which modellers were challenged to compute the wind field at a forested site with moderately complex topography. The task was to model the wind field in stationary conditions with neutral stratification by using the wind velocity measured at 100 m at a metmast as the only reference. Detailed maps of terrain elevation and forest densities were provided as the only inputs, derived from airborne laser scans (ALSs) with a resolution of 10 m × 10 m covering an area of 50 km × 50 km, that closely match the actual forest and elevation of the site. The participants were free to apply their best practices for the simulation to decide the size of the domain, the value of the geostrophic wind, and every other modelling parameter. The comparison of the results with the measurements is shown for the vertical profiles of wind speed, shear, wind direction, and turbulent kinetic energy. The ALS-based data resulted in reasonable agreement of the wind profile and turbulence magnitude. The best performance was found to be that of large-eddy simulations using a very large domain. For the Reynolds-averaged Navier–Stokes type of models, the constants in the turbulence closure were shown to have a great influence on the yielded turbulence level, but were of much less importance for the wind speed profile. Of the variety of closure constants used by the participating modellers, the closure constants from Sogachev and Panferov (2006) proved to agree best with the measurements. Particularly the use of Cμ≈0.03 in the k–ε model obtained better agreement with turbulence level measurements. All except two participating models used the full detailed ground and forest information to model the forest, which is considered significant progress compared to previous conventional approaches. Overall, the article gives an overview of how well different types of models are able to capture the flow physics at a moderately complex forested site.

AB - This article describes a study in which modellers were challenged to compute the wind field at a forested site with moderately complex topography. The task was to model the wind field in stationary conditions with neutral stratification by using the wind velocity measured at 100 m at a metmast as the only reference. Detailed maps of terrain elevation and forest densities were provided as the only inputs, derived from airborne laser scans (ALSs) with a resolution of 10 m × 10 m covering an area of 50 km × 50 km, that closely match the actual forest and elevation of the site. The participants were free to apply their best practices for the simulation to decide the size of the domain, the value of the geostrophic wind, and every other modelling parameter. The comparison of the results with the measurements is shown for the vertical profiles of wind speed, shear, wind direction, and turbulent kinetic energy. The ALS-based data resulted in reasonable agreement of the wind profile and turbulence magnitude. The best performance was found to be that of large-eddy simulations using a very large domain. For the Reynolds-averaged Navier–Stokes type of models, the constants in the turbulence closure were shown to have a great influence on the yielded turbulence level, but were of much less importance for the wind speed profile. Of the variety of closure constants used by the participating modellers, the closure constants from Sogachev and Panferov (2006) proved to agree best with the measurements. Particularly the use of Cμ≈0.03 in the k–ε model obtained better agreement with turbulence level measurements. All except two participating models used the full detailed ground and forest information to model the forest, which is considered significant progress compared to previous conventional approaches. Overall, the article gives an overview of how well different types of models are able to capture the flow physics at a moderately complex forested site.

KW - Renewable energy sources

KW - TJ807-830

U2 - 10.5194/wes-3-929-2018

DO - 10.5194/wes-3-929-2018

M3 - Journal article

VL - 3

SP - 929

EP - 946

JO - Wind Energy Science

JF - Wind Energy Science

SN - 2366-7443

IS - 2

ER -