The paper discusses several aspects of the construction of approaches that combine statistical (RANS) models with large eddy simulation, with the objective of making LES an economically viable method for predicting complex, high-Reynolds-number turbulent flows. The first part provides a review of alternative approaches, highlighting their rationale and major elements. Next, two particular methods are introduced in greater detail - one based on coupling near-wall RANS models to the outer LES domain on a single contiguous mesh, and the other involving the application of the RANS and LES procedures on separate zones, the former confined to a thin near-wall layer. Examples for their performance are included for channel flow and, in the case of the zonal strategy, for three separated flows. Finally, a discussion of prospects is given, as viewed from the writer's perspective.

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[in Japanese]

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The nonlinear bifurcation analysis is employed to investigate the effect of the system rotation to the fluid flow in a vertical slot laterally heated. It is observed that secondary and tertiary solutions are annihilated by the rotation oriented in the streamwise direction. Moreover, we found a quasi 2-dimensional solution, which supercritically connects the tertiary solutions.

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[in Japanese]

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Static pressure fluctuations are an important ingredient in turbulence, but little is known about it. We have developed the accurate pressure measurement technique. The results were carefully compared with DNS results. In this study this technique is extended into the pressure gradient measurement and two point correlation measurement. Also, new idea to correct the HR resonance and low frequency fluctuation is presented. The acceleration vector is given by N.S. equation as follows; a^^→=∇(p/ρ)+v∇^2u^^→. In a fully developed turbulence, the viscous damping term is small compared with the pressure gradient term, therefore, the acceleration is closely related to the pressure gradient, and particle acceleration is evaluated by measuring the instantaneous pressure fluctuations.

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