A special case that stands out in thermosolutal convection is that for which the thermal and solutal convection forces are equal and generate opposite effects (N = −1). This antagonistic effect between the two buoyancy forces is expected to generate unpredictable and unique behaviors when combined with thermodiffusion and internal heating phenomena. The present numerical study is dedicated to this particular case considering a binary mixture confined in a vertical rectangular cavity with an aspect ratio A = 2. The lattice Boltzmann method with multiple relaxation time is used to analyze the effect of the control parameters which are the Soret parameter (Sr = −0.5, 0 and 0.5), and the internal to external Rayleigh numbers ratio (0 ≤ R ≤ 80) while maintaining constant the external Rayleigh number (Ra_E = 10⁵), the Prandtl number (Pr = 0.71) and the Lewis number (Le = 2). The results obtained show that, in the absence of Soret effect, there are three small ranges of R characterized by flow instabilities. These ranges are located below R = 1.85. The increase of R may accentuate or attenuate the complexity of the oscillations depending on the range of the heating parameter. It is also shown that the positive value of the Soret parameter leads to a stabilizing effect of thermodiffusion by eliminating the instabilities, while the negative value of this parameter engenders an extension of the instability range until R = 20, accompanied by important changes in terms of behaviors.

在热溶质对流中突出的一个特殊情况是热对流力和溶质对流力相等并产生相反效果 ( N = -1)。当与热扩散和内部加热现象相结合时，两种浮力之间的这种对抗作用预计会产生不可预测的独特行为。目前的数值研究专门针对这种特殊情况，考虑限制在纵横比A  = 2 的垂直矩形腔中的二元混合物。使用具有多个弛豫时间的晶格 Boltzmann 方法来分析控制参数的影响，即 Soret参数 ( Sr = −0.5, 0 和 0.5)，以及内部与外部瑞利数比 (0 ≤  R ≤ 80) 同时保持外部瑞利数 ( Ra _E  = 10 ⁵ )、普朗特数 ( Pr = 0.71) 和路易斯数 ( Le = 2)不变。获得的结果表明，在没有 Soret 效应的情况下，存在三个以流动不稳定性为特征的小范围的R。这些范围位于R  = 1.85 以下。R的增加取决于加热参数的范围，可能会加剧或减弱振荡的复杂性。还表明，Soret 参数的正值通过消除不稳定性导致热扩散的稳定作用，而该参数的负值导致不稳定范围扩大，直到R  = 20，伴随着重要的变化行为。