CAJ | 학술논문

壁面湍流脉动压力是重要的流噪声声源，对壁面湍流脉动压力及其波数-频率谱进行数值计算是流声耦合领域的重要课题，开展相应的研究十分必要。文章采用大涡模拟方法（LES）结合动态亚格子涡模型（DSL）与千万量级的精细网格，对平板壁面湍流脉动压力及其波数-频率谱进行了数值计算，并与试验结果进行了对比分析，验证了数值计算方法的可靠性。首先，介绍了大涡模拟的物理内涵与基本方程，给出了所采用亚格子涡模型的表达式。其次，描述了Abraham试验中矩形试验段的几何特征，给出了网格的剖分形式，并给出了相应的离散求解数值方法以及边界条件的设置。再次，探讨了湍流脉动压力变化规律及其相似律，基于Fourier变换计算得到了湍流脉动压力波数-频率谱，并详细讨论了壁面湍流脉动压力及其波数-频率谱计算值与试验值之间的差异，进行了定量与定性的验证分析，结果表明，计算结果与试验结果吻合良好，计算方法合理可靠，为今后复杂几何模型壁面湍流脉动压力及其波数-频率谱的计算研究工作奠定了基础。最后，基于试验和计算结果，比较分析了常用波数-频率谱理论模型，为波数-频率谱的工程应用提供了参考。
벽면단류맥동압력시중요적류조성성원，대벽면단류맥동압력급기파수-빈솔보진행수치계산시류성우합영역적중요과제，개전상응적연구십분필요。문장채용대와모의방법（LES）결합동태아격자와모형（DSL）여천만량급적정세망격，대평판벽면단류맥동압력급기파수-빈솔보진행료수치계산，병여시험결과진행료대비분석，험증료수치계산방법적가고성。수선，개소료대와모의적물리내함여기본방정，급출료소채용아격자와모형적표체식。기차，묘술료Abraham시험중구형시험단적궤하특정，급출료망격적부분형식，병급출료상응적리산구해수치방법이급변계조건적설치。재차，탐토료단류맥동압력변화규률급기상사률，기우Fourier변환계산득도료단류맥동압력파수-빈솔보，병상세토론료벽면단류맥동압력급기파수-빈솔보계산치여시험치지간적차이，진행료정량여정성적험증분석，결과표명，계산결과여시험결과문합량호，계산방법합리가고，위금후복잡궤하모형벽면단류맥동압력급기파수-빈솔보적계산연구공작전정료기출。최후，기우시험화계산결과，비교분석료상용파수-빈솔보이론모형，위파수-빈솔보적공정응용제공료삼고。
Turbulent wall pressure fluctuations beneath turbulent boundary layers are important sources of flow noise. The computation of wall pressure fluctuation and its wavenumber-frequency spectrum is a hot topic in the field of flow-acoustic coupling. It is necessary to carry out corresponding research. In this pa-per, wall pressure fluctuation and its wavenumber-frequency spectrum are computed using large eddy sim-ulation (LES) with approriate sub-grid scale model, grid number and discretization methods. The results are compared with the experiment of Abraham and discussed in detail. Firstly, some fundamentals of the nu-merical simulation are presented, including the philosophy of LES, formulations of sub-grid scale models, discretization methods and boundary conditions, etc. Secondly, the rectangular test section of Abraham’s experiment and its computational domain are depicted. Thirdly, the scaling of turbulent wall pressure fluc-tuations and its variations due to different free stream velocities are discussed. The wavenumber-frequency spectra of turbulent wall pressure fluctuations are computed by taking FFT of the correlation function of the simulation data, the computed spectra of the wall pressure fluctuations are compared with those of Abra- ham’s experiment and analyzed qualitatively and quantitatively. Finally, comparison of typical theoretical models of wavenumber-frequency spectra is made based on computational and Abraham’s experimental results. Groundwork is made for further research in turbulent wall pressure fluctuation and its wavenumberfrequency spectrum.