A study is made of steady axisymmetric flows of a doublediffusive stratified fluid in a differentially-rotating cylinder. The previous studies on the flow of a single-diffusive fluid are extended to the case of double-diffusive fluid flows. The rotational Reynolds number is large and the overall stratification number is 0(1). The fluid system is thermally stable and solutally unstable ; the overall density profile is gravitationally stable. The study is centered on the usual cases of the aspect ratio, A(= height/radius)∼0(1), but extreme cases, i. e., A ≫1 and A≪ 1, are also dealt with. Finite-difference techniques are employed to integrate the full Navier-Stokes equations. Results on the structures of flow, temperature and solute fields are presented. Specific comparisons are made with the flows of a single-diffusive fluid. For aspect ratios 0(1), the main body of the flow field is characterized by the thermal-wind relation. As the effect of double-diffusion increases, the meridional fluid transport intensifies ; the effective stratification decreases. These can be interpreted by the fountain effect. The solute boundary layers become very thin at large Lewis numbers. The effective stratification increases with the Prandtl number. For small aspect ratios, the flow field is principally occupied by strong shear flows and the effect of stratification is minor. The influence of double-diffusion on the flow is insubstantial. For large aspect ratios, the bulk of the flow field is in state of rigid body rotation. The fountain effect becomes appreciable only when the meridional flows are significant ; the impact of double-diffusion is unimportant in the bulk of the flow field.
회전하고 있는 용기내에 확산계수가 다른 두 가지 이상의 성분이 존재하는 이중확산 유체의 유동은 많은 실제 현상에서 응용과제로 대두되고 있다.
본 논문에서는 단일확산 성층화 유체의 회전유동에 관한 기존의 연구를 이중확산 유체의 범위까지 확장하였으며, 또한 형상비의 영향도 고려하였다.
회전하고 있는 원통용기내에서의 이중확산 유체의 경우, 같은 조건의 단일확산 유체의 경우보다 유효 성층화 정도가 약하였으며 이러한 현상은 fountain 효과로 설명할 수 있다. 그러나 형상비가 매우 크거나 작은 경우에는 이러한 이중확산의 영향이 매우 미소하다.
