In this study, the effect of natural convection affected by gas radiation on a spatially developing boundary layer was investigated through large-eddy simulations to evaluate the interaction between natural convection and thermal radiation in an open environment, wherein Tollmien–Schlichting instabilities dominate. The gas radiation was calculated using the discrete ordinate method considering gray gas as the medium, and the effect of the absorption coefficient of the medium on the boundary layer has been discussed. With gray gas medium with small and large absorption coefficient values, a turbulent boundary layer was observed, while with intermediate absorption coefficient values, little turbulence was observed. As the gas heated due to radiation, the thermal boundary layer thickness increased. With the thickening of the thermal boundary layer, the magnitude of the velocity gradient at the inflection point decreased, stabilizing the flow and damping the thermal boundary layer fluctuations owing to the Tollmien–Schlichting mechanism. The transition to turbulence of the boundary layer could be reduced when the fluid far from the heated wall was heated through thermal radiation and the shear stress at the infection point decreased. These results provide insights for the control of turbulence for natural convection.

在这项研究中，通过大涡模拟研究了受气体辐射影响的自然对流对空间发展边界层的影响，以评估开放环境中自然对流和热辐射之间的相互作用，其中 Tollmien-Schlichting 不稳定性占主导地位。以灰色气体为介质，采用离散纵坐标法计算气体辐射，讨论了介质吸收系数对边界层的影响。灰色气体介质在吸收系数值小的和大的情况下，观察到湍流边界层，而对于中等吸收系数值，几乎没有观察到湍流。随着气体因辐射而加热，热边界层厚度增加。随着热边界层的增厚，由于 Tollmien-Schlichting 机制，拐点处速度梯度的大小减小，稳定了流动并抑制了热边界层的波动。当远离受热壁的流体通过热辐射加热并且感染点处的剪应力降低时，可以减少边界层向湍流的转变。这些结果为控制自然对流湍流提供了见解。当远离受热壁的流体通过热辐射加热并且感染点处的剪应力降低时，可以减少边界层向湍流的转变。这些结果为控制自然对流湍流提供了见解。当远离受热壁的流体通过热辐射加热并且感染点处的剪应力降低时，可以减少边界层向湍流的转变。这些结果为控制自然对流湍流提供了见解。