以數值計算方法評估方柱形狀建築物之受風效應

Evaluation of Wind Effect of a Square Prism by Numerical Simulation

本研究以大氣邊界層中平坦空曠地形上高寬比為4 之單一方柱為基準問題，先以風洞建築模型試驗量取風場與柱體之風力係數作為數值模擬結果驗證之基本資料，繼以微可壓縮流的計算流體動力學數值方法，配合以空間平均的大渦模擬與次網格紊流模型進行風場之計算，並將數值與量測結果相互比對驗證，進而評估數值模擬在建築風力分析之適用性與可行性。最後，研究中再依據數值模擬結果與風洞實驗數據之比對與探討，初步研擬工程實務上可接受的CFD 模擬參考原則。

In the study, a single square building with an aspect ratio of 4 in a flat territory is set as the benchmark problem to assess how the application of numerical simulation is valid for the evaluation of the wind effects of the building. Wind tunnel measurements were firstly performed to measure the force coefficients associated with a building model and the results were taken as the basis for the verification of the numerical results. Numerical simulations, based on a weakly-compressible-flow method with a space-averaged large-eddy-simulation technique and a subgrid-scale turbulence model, were then carried out in parallel and the results were compared to the measurement data. After the accuracy and validity of the numerical method was verified, extensive numerical investigations were conducted to propose certain general guidelines for the applications of CFD methods in evaluating the wind effect buildings.