| Project/Area Number |
20K14889
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 23020:Architectural environment and building equipment-related
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| Research Institution | Hiroshima University (2021)
Niigata Institute of Technology (2020) |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2021: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2020: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
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| Keywords | Urban airflow simulation / Stochastic optimization / Accuracy improvement / CFD / Calibration / Turbulence mode / Pedestrian / Shape optimization / Wind Environment / Model optimization / Acuraccy / Rapidity / Urban airflow |
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| Outline of Research at the Start |
In this research, a systematic framework for improving the accuracy of two-equation RANS turbulence models will be proposed in which different statistical and approximation models, machine-learning tools, and optimization solvers are utilized to optimize the RANS closure coefficients for urban flows in five steps: 1)Case study definition, 2) High-quality data acquisition and validation metrics definition, 3)Development of a stochastic optimization solver for RANS parameters, 4) Calibration of RANS models for Benchmarks, 5) Development of adaptive correlations for RANS closure coefficients.
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| Outline of Final Research Achievements |
The computational fluid dynamics (CFD) models based on the Reynold-averaged Navier-Stoke (RANS) turbulence modes are frequently used for urban air simulations because of their low computational cost. However, their accuracy is not so high in the weak wind regions in street canyons. The default values of the RANS’ closure coefficients are adapted from other fields, which are not perfectly suitable for urban airflow simulations. Hence, in this study, a systematic approach was proposed to find the optimum values for the RANS’ closure coefficients by using a novel stochastic optimization method to significantly improve the computational accuracy and rapidity of urban CFD simulations. Different benchmarks, ranging from simple buildings to buildings in an actual city were considered to demonstrate the applicability of the proposed framework.
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| Academic Significance and Societal Importance of the Research Achievements |
This research results help the CFD users to increase the accuracy of their numerical prediction and finally can improve the reliability of practical designs in urban applications in cities to have more sustainable and safe cities.
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