大規模乱流場中の乱流熱拡散に関する風洞実験(乱流熱物質拡散・伝達(2),一般講演)

概要

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Thermal diffusion was experimentally investigated in turbulent shear flow fields and quasi-isotropic turbulence fields. A thermal jet was ejected from a pipe of 5.4mm in diam. in the large-scale turbulence fields of R_λ=310〜490. Taylor's short-time dispersion accompanied by the plume's meandering motion was realized in the large-scale turbulence fields. The influences of velocity gradient on the thermal diffusion were examined in the turbulent shear flow by comparing with the results of a quasi-isotropic turbulence. Temperature fluctuation and two velocity fluctuation components were simultaneously measured by a high precision thermo-anemometer system. In the case of sheared grid turbulence, the plume was transported to the lower velocity side by the effect of Reynolds stress. Meandering motion of the plume was caused by the large scale turbulent eddies, also in the large-scale turbulent shear flow fields, where the streamwise growth of the plume width was affected by the local values of the turbulent eddy scale.
日本流体力学会の論文
2007-08-06