The Effect of Large-Scaled Eddies in the Wind Flows on the Windbreak of Forest Canopies
| Project/Area Number |
11650182
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | Miyazaki University |
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Principal Investigator |
HIRANO Kimitaka Miyazaki University, Department of Mechanical Systems Engineering, professor, 工学部, 教授 (40094081)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1999: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | forest canopy / wind tunnel testing / finite difference method / turbulent energy / leaf area index / wind break / 植生流体力学 / 大気乱流 / エネルギー減衰 / 数値シミュレーション / 環境流体力学 |
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| Research Abstract |
The effect of the large-scaled eddies in the wind flows on the windbreak function of forest canopies is analyzed with two methods, wind tunnel testing and numerical simulation.
(1) As the first approximation of turbulent flows, uniformly oscillating flows are made in the multi-fun wind tunnel. Forest canopy models are placed in this oscillating flow. At the downstream region of the canopies, time-mean velocity profile, intensity of turbulence and Reynolds stress are measured with the CTA anemometer. Intensity of turbulence in the oscillating flows is stronger at above and below crowns of forest canopies.
(2) The linear shear flows with about 20 % intensity of turbulence are made in the wind tunnel. Effects of shear and turbulence in the main flows are measured on the downstream region of the forest canopy models. In the high-leveled turbulent flows the windbreak effect of forest canopy is decreased because vertical diffusion of momentum is enhanced by turbulence.
(3) Flow fields are simulated with the FDM-SMAC method. The crowns of canopy are approximated with a lot of particles that are connected with neighbor particles by spring and damper. The motion of air flows and the motion of particles in the crown are linked in the time-marching. Flow fields around the canopies of various sparse and dense crowns are calculated numerically. These results are good agreement with the results of the experiments with the wind tunnel testing.
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Report
(3 results)
Research Products
(14 results)
