Study on Numerical Prediction of Aeroacoustic Noise Radiated from Balusters of Buildings

建筑物栏杆辐射气动声噪声数值预测研究

• 批准号: 12450231
• 负责人: HIRATE Kotaroh
• 金额: $ 4.8万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450231/
• 关键词: Building Exterior Subsidiaries; Aeroacoustics; Numerical Analysis; CFD; Bluff Body; Computational Cost Reduction; LES; Sound Source Correlation; 強風; 空力騒音; Lighthill-Curle 理論; 流入風向; 放射音圧推定; 相関係数; Lighthill-Curle理論; Smagorinskyモデル

True-scale analysis : Sound generation by airflow over square-section balusters of buildings is numerically calculated by a hybrid technique of near-field incompressible flow analysis and far-field integral of Curle equation. Under the conditions of inflow wind velocity of 12m/s and the side length of the square-section balusters of 21mm (the Reynolds number 16,000), the result approximately matched an experimental result in peak frequency, which is higher in Strouhal number than the case of an isolated square cylinder in the same Reynolds number.Computational cost reduction method : An estimation method of total sound pressure radiated from such body is introduced by conducting an analysis of its partial span, taking frequency-dependent spanwise correlation of the fluctuating aeroacoustic source into account. The presented method is validated through comparison of the sound pressure estimated by the method and that obtained by a full-span analysis.Extension to the method above : To reduce computational resources required for CFD computation further, the authors present a method to estimate the noise from a row of cylinders like balusters by computing its part. The idea is to extrapolate the sound pressure obtained by partial computation using correlation function of the phase angles of fluid forces at each frequency between the cylinders. A computation of a balustrade with eight balusters with the method applied is attempted, where correlation is hardly observed even at the Karman frequency.

真实比例分析：本文采用近场不可压缩流动分析和Curle方程远场积分相结合的方法，对气流绕建筑物方形截面栏杆的声辐射进行了数值计算。在来流风速为12 m/s，方形截面栏杆边长为21 mm的条件下，（雷诺数16，000）时，计算结果与实验结果在峰值频率上基本一致，在相同雷诺数下，Strouhal数下的峰值频率高于孤立方柱的峰值频率。通过对该类物体部分翼展的分析，提出了一种估算该类物体辐射总声压的方法，该方法考虑了脉动气动声源的频率相关展向相关性。通过与全跨分析结果的比较，验证了该方法的有效性。对上述方法的扩展：为了进一步减少CFD计算所需的计算资源，提出了一种通过计算一排圆柱体（如栏杆）的一部分来估计其噪声的方法。其思想是外推的声压获得的部分计算使用相关函数的相位角的流体力在每个频率之间的气缸。用该方法计算了一个有八根栏杆的栏杆，即使在卡门频率下也几乎没有观察到相关性。