AM05-12-015 鉛直平板間の自然対流場における秩序構造の再生(乱流渦構造3,一般講演)

概要

論文の詳細を見る
To develop the effective method of heat transfer in natural convection, Direct Numerical Simulations (DNS) of differentially heated vertical slot is conducted Rayleigh number (Ra) which is defined with the slot width and the temperature difference between both walls, is 5.4×10^4. Since it is found in our previous works that the large-scale high/low speed regions, streaky structures are dominant in the core region, their behavior is examined with the minimal channel flow. The most part of regeneration cycle is similar to that of near-wall turbulence in forced convection, i.e. streaky structure is generated and then broken repeatedly. Meanwhile it is reveled via two simplified model simulations that markedly difference exists in the occurence of streaky structures, that is, the streaky structures in forced convection are generated due to the conversion of vortical flow, but in natural convection buoyancy force contributes to the generation of streaky structures. And also it is demonstrated that these structures govern the heat transfer on the wall and that the regeneration cycles are established in the case of larger Ra=5.4×10^5.
2005-09-05