紊流邊界層特性之數值模擬

隨著科技發展、醫學進步，人口逐漸現象，但在有限的土地上求生活空間，所以建築物有向上發展的趨勢，加上政府近年來推動都市更新的計畫，都市中存在著越來越多的高層建築。因此我們若要探討紊流邊界層流場上的特性，勢必要進行風洞實驗的模擬。如果要進行一個真實地形的邊界層模擬，在製作該地形的縮尺模型上需要耗費大量的人力與時間。本研究希望能藉由計算流體力學(CFD)模擬出紊流邊界層特性。本研究主要是使用大渦模擬法(LES)去模擬風場中的大氣邊界層，對紊流邊界層的模擬結果會與風洞實驗室的實驗結果對照；探討方向部分為。首先，第一部份在模擬大氣邊界層風速剖面的風場，在本研究入流口給予淡江大學風洞實驗室邊界層數據，即給予平均風速（mean velocity）、紊流能量（turb_kinetic_e）、紊流消散率（turb_dissipati），並將這些數據輸入Fluent 進行模擬大氣邊界層的紊流特性，此方法為Fluent 內置頻譜生成法。第二部份同樣的在本研究入流口給予淡江大學風洞實驗室邊界層數據，利用AR 時間序列模擬出不同高度的風速歷時，再使用User Define Functions (UDF)輸入模擬出大氣邊界層的紊流特性，此方法為AR 時間序列模擬頻譜合成法。兩種方法在分析模擬上都在地面給予表面剪應力當作在風洞實驗室在地面的粗糙元素，在距離上游入流32D 的位置會是我們放置建築物的位置，而模擬出來的風場能吻合實驗室的紊流邊界層特性。

關鍵字

數值模擬； LES ； AR時間序列；大氣邊界層

並列摘要

This study is the characteristics of the turbulent boundary layer flow field were simulated by large-eddy simulation method. The simulation results of atmospheric turbulent boundary where compare with those of wind-tunnel test.There are second parts would be study. First, a velocity profiles in the simulated atmospheric boundary layer wind field in the inflow port of this study give Tamkang University wind tunnel boundary layer data, giving the average wind speed (mean Velocity) turbulence energy (turb_kinetic_e,), the turbulent dissipation rate (turb_dissipati), and data input Fluent to simulate the atmospheric boundary layer turbulence characteristics. This method for the synthesis Fluent internal spectrum. Second,a part of the inflow port of this study give the same Tamkang University wind tunnel boundary layer data, the use of AR time series to simulate the different heights of wind speed lasted, and then use the User Define Functions (UDF) input to simulate the atmospheric boundary layer tangledThe flow characteristics of this spectrum synthesis method for AR time series simulation. Two methods in the analysis of simulation are given in the ground surface shear stress as in the rough elements of the wind tunnel laboratory on the ground. We assume place the location of the buildings at a distance upstream inflow 32D,simulation of wind field can effectively consistent with laboratory turbulent boundary layer characteristics

並列關鍵字

Numerical simulation ； LES ； boundary layer ； Autoregressive

參考文獻

Yi Yang a, MingGu ,, SuqinChen , XinyangJin , (2009) “New inflow boundary conditions for modelling the neutral equilibrium atmospheric boundary layer in computational wind engineering” Journal of Wind Engineering and Industrial Aerodynamics, pp. 88–95

[2]. Richards, P.J., Quinn, A.D., “A 6m cube in an atmosphere boundary layer flow, part 2. Computational solutions.” Wind and Structures 5, pp. 177–192.

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[5]. S.H. Huang , Q.S.Li , J.R.Wu , (2010) A general inflow turbulence generator for large eddy simulation. Journal of Wind Engineering and Industrial Aerodynamics

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國際替代計量

紊流邊界層特性之數值模擬

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