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ISSN Онлайн: 2642-0554

PREDICTIONS OF WALL-PRESSURE FLUCTUATION IN SEPARATED COMPLEX FLOWS WITH IMPROVED LES AND QUASI-DNS

Masahide Inagaki
Toyota Central Research & Development Laboratories, Inc., Nagakute, Aichi 480-1192, Japan

Nariaki Horinouchi
Digital Engineering Lab., Toyota Central Research & Development Laboratories, Inc. Nagakute, Aichi 480-1192, Japan

Ken-ichi Ichinose
Vehicle Engineering Div., Toyota Motor Corporation Toyota-cho, Toyota, Aichi 471-8571, Japan

Yasutaka Nagano
Nagoya Industrial Science Research Institute; Department of Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan

Аннотация

To seek a practical methodology for predicting the wall-pressure fluctuation associated with the aerodynamic noise radiated from the flow around bluff bodies at low Mach number, we conducted some calculations of the flow around a circular cylinder, which includes some LES using the Smagorinsky model, the dynamic Smagorinsky model and a new mixed-time-scale SGS model (Inagaki et al. 2002a), as well as Quasi-DNS. The comparative results are examined, revealing that LES with the new mixed-time-scale SGS model is most accurate in predicting not only the mean flow field and turbulent intensities but also the wall-pressure fluctuation, and is more stable than the dynamic model. It is also confirmed that Quasi-DNS is less accurate than LES using any SGS model, and that LES using QUICK scheme for the convection term gives similar results to those obtained by Quasi-DNS. Furthermore, calculations of the flow around a simplified front-pillar model of an automobile are also performed. The corresponding experiment shows that the wall-pressure fluctuation has a wide-range spectrum. The results of LES using the new SGS model show better agreement with the experimental data in a high-frequency range than those of quasi-DNS. Thus, it is concluded that LES with the mixed-time-scale SGS model is an effective method for predicting certain kinds of wall-pressure fluctuations.