Guidebook for CFD Predictions
of Urban Wind Environment
Architectural
Institute of Japan
Committee members
Japanese Page
Introduction
As computer facilities and Computational Fluid Dynamics (CFD) software have been significantly improved in recent years, the prediction and the assessment of pedestrian wind environment around buildings using CFD have become practical at design stages. Therefore, best practice guidelines, which summarize important points of using CFD technique for appropriate prediction of pedestrian wind environment, are needed. In 2007, the Architectural Institute of Japan (AIJ) published a guidebook [1] including the basics of wind engineering and CFD, the results of extensive cross comparisons between CFD simulation results and high-quality wind-tunnel experiments [2, 18], and the guidelines [19]. The feature of the guidelines was that it is based on the results of the cross comparison between the results of CFD predictions, wind tunnel tests and field measurements for the seven test cases, which have conducted for investigating the influence of many kinds of computational conditions for various flow fields [18].
The guidebook published in 2007 [1] basically expects the application of steady Reynolds-averaged Navier–Stokes equations (RANS) model to pedestrian wind environment problem. However, in recent years, increasing access to computing power has led to the computations using large-eddy simulation (LES). In 2020, the AIJ published an expanded and revised guidebook considering the recent expansion of the CFD applications to various wind environment problems in built-up areas. At this time, the guidebook is available in only Japanese.
Validation Benchmark Tests
In order to clarify the major factors which affecting the prediction accuracy, the AIJ carried out cross comparisons of wind tunnel experiments, field measurements and CFD results of flow around a single high-rise building placed within the surface boundary layer, flow within a building complex in an actual urban area, and flow around a tree, obtained from various k-ε models, DSM and LES for the guidebook (2007) [1, 18].
The detailed results of the benchmark tests conducted by the AIJ is available for purchase in the following link [2]:
http://www.aij.or.jp/eng/publish/index_ddonly.htm
The validation benchmark tests are much expanded for the guidebook published in 2020.
The following table shows the models for comparative and parametric studies as investigated by the working group. The boundary conditions and the experimental results for each case are available. By clicking on a data set name in the table, you can directly access to the individual dataset files (EXCEL) and CAD files. The geometry, the inflow boundary conditions and the measuring points for the experiment are described in their worksheets.
|
test case |
dataset |
Ref. |
||
|
A |
1:1:2 shape building model |
|
Data file : CaseA(1_1_2).xls |
[3] |
|
B |
1:4:4 shape building model |
|
Data file : CaseB(1_4_4).xls |
[5] |
|
C |
Simple building blocks |
|
Data file : CaseC(City_blocks).xls |
[6] |
|
D |
A high-rise building in city blocks |
|
Data file : CaseD(Highrise+Blocks).xls |
[14] |
|
E |
Building complexes with simple building shape in actual urban area (Niigata) |
|
Data file : CaseE(Niigata).xls |
- |
|
F |
Building complexes with complicated building shape in actual urban area (Shinjuku) |
|
Data file : CaseF(Shinjuku).xls |
[7][8] |
|
G |
Two-dimensional pine tree |
|
Data file : CaseG(Tree).xls |
[9] |
|
H |
1:1:2 shape building model with dispersion |
|
Data file : CaseH(Iso_1_1_2).xlsx |
[10] |
|
I |
A cubic building model with dispersion |
|
Data file : CaseI(Cube_AIST).xlsx |
[11][12] |
|
J |
1:1:2 shape building model with dispersion in Non-isothermal flow |
|
Data file : CaseJ(NonIso_1_1_2).xlsx |
[10] |
|
K |
Cube arrays with point-source dispersion |
|
Data file : CaseK(Arrays).xlsx |
- |
|
L |
Cube arrays with line-source dispersion in non-isothermal flow |
|
Data file : CaseL(NonIso_Arrays).xlsx |
[13] |
|
M |
Campus building model with dispersion (TPU) |
|
Data file : CaseM(TPU).xlsx |
[14][20] |
AIJ guidelines for practical applications of CFD to pedestrian wind environment around buildings [19]
The guidelines for practical application of CFD to the pedestrian wind environment around buildings were proposed by the working group of the AIJ in 2008 [1, 18]. They are based on the results of cross-comparison between CFD predictions, wind tunnel test results and field measurements for seven test cases, which have been conducted to investigate the influence of many kinds of computational conditions for various flow fields. They summarize important points in using CFD techniques to predict the pedestrian wind environment. The authors believe that the guidelines presented here give useful information for predicting and assessing the pedestrian wind environment around buildings using CFD. The results of cross-comparisons for the seven test cases conducted within this project will be utilized to validate the accuracy of CFD codes used in the practical applications of wind environment assessments. The AIJ is currently establishing appropriate LES guidelines for the pedestrian wind environment in built-up areas [16].
Time-dependent Inflow Turbulence Data
Inflow turbulence data that can be used to perform LES analysis for Case H, Case K, and Case M of the experiments in this validation database can be downloaded from the following links. This inflow turbulence data was created by performing an LES analysis that reproduced the spires and roughness blocks in the wind tunnel where the experiments were conducted [15-17, 21].
Refer to this document for notes on the use of the data.
http://news-sv.aij.or.jp/kankyo/s35/data/20200130/inflow.7z.001
http://news-sv.aij.or.jp/kankyo/s35/data/20200130/inflow.7z.002
http://news-sv.aij.or.jp/kankyo/s35/data/20200130/inflow.7z.003
http://news-sv.aij.or.jp/kankyo/s35/data/20200130/inflow.7z.004
http://news-sv.aij.or.jp/kankyo/s35/data/20200130/inflow.7z.005
http://news-sv.aij.or.jp/kankyo/s35/data/20200130/inflow.7z.006
http://news-sv.aij.or.jp/kankyo/s35/data/20200130/inflow.7z.007
http://news-sv.aij.or.jp/kankyo/s35/data/20200130/inflow.7z.008
(These are compressed in 7zip format and divided into eight files.)
References
[1] Architectural Institute of Japan, 2007. Guidebook for Practical Applications of CFD to Pedestrian Wind Environment around Buildings. Architectural Institute of Japan.
[2] Architectural Institute of Japan, 2016. AIJ benchmarks for validation of CFD simulations applied to pedestrian wind environment around buildings. Architectural Institute of Japan. ISBN978-4-8189-5001-6. (English Download sales only) https://www.aij.or.jp/eng/publish/index_ddonly.htm
[3] Meng, Y., Hibi, K., 1998. Turbulent measurements of the flow field around a high-rise building. Journal of Wind Engineering, Japan Association for Wind Engineering, 76, 55-64. (in Japanese) https://doi.org/10.5359/jawe.1998.76_55
[4] Uehara, K., Wakamatsu, S., Ooka, R., 2003. Studies on critical Reynolds number indices for wind-tunnel experiments on flow within urban areas. Boundary-Layer Meteorology, 107, 353-370. https://link.springer.com/article/10.1023/A:1022162807729
[5]Miyazaki, T., Tominaga, Y., 2003. Wind tunnel experiment on flow field around a building model with a scale ratio of 4:4:1 placed within the surface boundary layer. Proceedings of Annual Meeting of Hokuriku Chapter, Architectural Institute of Japan, 201-204. (in Japanese) https://www.aij.or.jp/paper/detail.html?productId=313933
[6] Nonomura, Y., Kobayashi, N., Tominaga, Y., Mochida, A., 2003. The cross comparison of CFD results for flow field around building models (part 3): The wind tunnel test for the varification models on the flowfield around building blocks. Japan Association for Wind Engineering, 95, 83-84. (in Japanese) https://doi.org/10.14887/jaweam.2003.0.41.0
[7] Fujii, K., Asami, Y., Iwasa, Y., Fukao, Y., et al., 1978. Wind in Shinjuku sub-central area: Comparison between field measurement and wind tunnel experiment. Proceedings of 5th Symposium on Wind Resistance of Structures, 91-98. (in Japanese)
[8] The Research Committee on Strong Wind Around High-rise Buildings, Development Council of Shinjuku Sub-central Area, 1985. Technical Report on Wind in Shinjuku Sub-central Area -Field Measurement, Experiment, and Observation. (in Japanese)
[9] Kurotani, Y., Kiyota, N., Kobayashi, S., 2001. Windbreak effect of Tsuijimatsu in Izumo Part. 2. Summaries of technical papers of annual meeting Architectural Institute of Japan, D-2, 745-746. (in Japanese) https://www.aij.or.jp/paper/detail.html?productId=241654
[10] Tokyo Polytechnic University, Wind Tunnel Experimental Database of Air Pollution around a Building: Database on Indoor / Outdoor Air Pollution. http://www.wind.arch.t-kougei.ac.jp/info_center/pollution/pollution.html
[11] National Institute of Advanced Industrial Science and Technology, 2011. Wind tunnel tests for validating the DiMCFD model. (in Japanese)
[12] National Institute of Advanced Industrial Science and Technology (in Japanese): https://unit.aist.go.jp/emri/ja/results/db/01/db_01.html
[13] Yoshie, R., Nomura, K., Katada, K., Jiang, G., 2012. Non-isothermal large eddy simulation of pollutant and thermal dispersion in urban street canyons. 22nd Proceedings of National Symposium on Wind Engineering, 61-66. (in Japanese) https://doi.org/10.14887/kazekosymp.22.0.61.0
[14] AIJ, 2015. AIJ Recommendations for Loads on Buildings (2015). (English Download sales only) http://www.aij.or.jp/eng/publish/index_ddonly.htm
[15] Ono H. et al., 2016. Data Storing Method for Large Eddy Simulation of Flow Around a Building, Proceedings of 11th OpenFOAM Workshop.
[16] Okaze, T., Kikumoto, H., Ono, H., Imano, M., Ikegaya, N., Hasama, T., Nakao, K. Kishida, T., Tabata, Y., Yoshie, R., Tominaga, Y., 2017. Large-Eddy Simulation of Flow around Buildings: Validation and Sensitivity Analysis. 9th Asia-Pacific Conference on Wind Engineering (APCWE9), Auckland, New Zealand, December 3-7, 2017. https://doi.org/10.17608/k6.auckland.5630887.v1
[17] Okaze,T., Kikumoto, H., Ono, H., Imano, M., Ikegaya, N., Hasama, T., Nakao, K., Kishida, T., Tabata, Y., Nakajima, K., Yoshie, R., Tominaga, Y., 2020. Benchmark test of flow field around a 1:1:2 shaped building model using LES: Influences of various calculation conditions on simulation result. Journal of Technology and Design, AIJ, 26(62), 179-184. (in Japanese) https://doi.org/10.3130/aijt.26.179
[18] Yoshie, R., Mochida, A., Tominaga, Y., Kataoka, H., Harimoto, K., Nozu, T., Shirasawa, T., 2007. Cooperative project for CFD prediction of pedestrian wind environment in the Architectural Institute of Japan. Journal of Wind Engineering and Industrial Aerodynamics, 95(9-11), 1551-1578. http://dx.doi.org/10.1016/j.jweia.2007.02.023
[19] Tominaga, Y., Mochida, A., Yoshie, R., Kataoka, H., Nozu, T., Yoshikawa, M., Shirasawa, T., 2008. AIJ guidelines for practical applications of CFD to pedestrian wind environment around buildings. Journal of Wind Engineering and Industrial Aerodynamics, 96(10-11), 1749-1761. http://dx.doi.org/10.1016/j.jweia.2008.02.058
[20] Tachibana, T., Yoshie, R., Nakayama, S., Kishida, T., Miyashita, K., Sasaki, R., 2022. Comparison between field measurement and wind tunnel experiments of gas dispersion in an urban area and verification of similarity law. Journal of Wind Engineering, 47(3), 39-52. (in Japanese) http://dx.doi.org/10.5359/jwe.47.39
[21] Okaze, T., Kikumoto, H., Ono, H., Imano, M., Ikegaya, N., Hasama, T., Nakao, K., Kishida, T., Tabata, Y., Nakajima, K., Yoshie, R., Tominaga, Y., 2021. Large-eddy simulation of flow around an isolated building: A step-by-step analysis of influencing factors on turbulent statistics. Building and Environment, 202, 108021. http://dx.doi.org/10.1016/j.buildenv.2021.108021