打印

作者

来源

URBAN FORESTRY & URBAN GREENING,Vol.34,P.29-43

语言

英文

关键字

CFD; Drag coefficient; Laser scanning; Urban tree; Wind; UNITED-STATES; LEAF-AREA; TREES; CANOPY; TURBULENCE; MODELS; TUNNEL; FOREST; PLANTS; JETS

作者单位

[Li, Yangyang; Law, Adrian Wing-Keung] Nanyang Technol Univ, Interdisciplinary Grad Sch, EPMC, Clean Tech One 05-PG119, Singapore 637141, Singapore. [Rahardjo, Harianto; Law, Adrian Wing-Keung] Nanyang Technol Univ, Sch Civil & Environm Engn, Block N1,1B-36,50 Nanyang Ave, Singapore 639798, Singapore. [Irvine, Kim Neil] Natl Inst Educ, Sch Humanities & Social Studies Educ, Block 03,03-155,1 Nanyang Walk, Singapore 637616, Singapore. Rahardjo, H (reprint author), Nanyang Technol Univ, Sch Civil & Environm Engn, Block N1,1B-36,50 Nanyang Ave, Singapore 639798, Singapore. E-Mail: chrahardjo@ntu.edu.sg; kim.irvine@nie.edu.sg; CWKLAW@ntu.edu.sg

摘要

The drag coefficients of one mature Khaya Senegalensis tree and one Eugenia Grandis tree in Singapore were analysed using computational fluid dynamics (CFD) modelling and validated with field measurements. For the numerical method, an innovative laser scanning approach was used to generate the tree geometries and to calculate the three-dimensional (3D) leaf area density distribution within the canopies. The canopies were represented by multiple porous domains and the turbulent effect of leaves was simulated by source and sink terms as a function of the calculated leaf area density. Computational fluid dynamics analyses using ANSYS 17.2 software were carried out on both leafless and leafed tree models. Three turbulent models, the Realizable k-epsilon model, Transition Shear Stress Transport model and Reynolds Stress Model were compared, and it was found that the differences in the drag forces among the turbulent models were negligible when they were meshed appropriately based on the grid independence study. The computed drag coefficient of the Khaya Senegalensis tree and the Eugenia Grandis tree from CFD modelling were similar within the range between 0.6 and 0.7. From field monitoring including the wind velocity and stem strains, the drag coefficients of both trees were calculated to be 0.51 and 0.40. Possible reasons causing the difference and limitations of the numerical method are discussed.