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Computational Fluid Dynamics (CFD) has been applied
in engineering predictions of turbulent fluid flow for
about two decades. Above all, turbulence modeling is
very important for predicting the performance of fluid
machines with sufficient reliability since most of them
involve complex turbulent phenomena. So far, the k-ε
model has been most frequently used to predict various
engineering turbulent flows with a certain degree of
success. On the other hand, with the recent advances
in computers, Large Eddy Simulation (LES) has become
applicable to engineering prediction. The advantages
of LES over the k-ε model are: (1) high prediction accuracy;
(2) capability of resolving the unsteadiness of turbulent
motion over a broad range of scales; (3) simplicity
of modeling the turbulent effects in fluid phenomena
containing multiphysics. For achieving the practical
use of LES, we have developed a new subgrid-scale (SGS)
model and a discretization method with high conservation
property in curvilinear grids. The present paper provides
descriptions thereof. In addition, the validity of LES
using these techniques is investigated in some basic
flows and engineering-relevant problems. LES is expected
to become a powerful engineering tool for analyzing
complex turbulent flows including heat and mass transfer,
aerodynamic noise generation, combustion and so forth.
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Air quality in auto-cabin is reported from various
viewpoints including recent trends.
Regarding the volatile organic compounds in the auto-cabin,
the generating mechanism, method of measurement from
within the auto-cabin, method of analysis, method of
measuring from the parts, etc. are introduced. Regarding
the odor, the generating mechanism, masking function,
relation with humidity, etc. are introduced along with
the characteristics of the human sense of smell. In
addition, the importance of ventilation of the air in
the auto-cabin is discussed.
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