Recent studies have suggested that a cyclonic vortex, which has the same signed vorticity as that of background shear, can lead to dissimilar heat transfer enhancement, i.e. more heat transfer than momentum transfer. However, it has not yet been known how the cyclonic vortex achieves dissimilarity, or if other types of vortices would also lead to dissimilarity. In order to tackle these problems, we introduce a straight vortex tube into laminar plane Couette flow under various conditions and numerically investigate heat and momentum transfer therein. The essential process for dissimilarity is isolated from complex ingredients of realistic flow to consider the interaction of a vortex with background shear. It is found that introduction of a strong spanwise anti-cyclonic vortex, which has the opposite signed vorticity to that of background shear, can realize more dissimilar heat transfer than the known cyclonic vortex as a consequence of the long-term interaction with the background flow, whereas the spanwise cyclonic vortex achieves larger dissimilarity in the early stage of its time evolution. The physical mechanisms of dissimilarity due to these vortices are elucidated by interpreting the distribution of the streamwise pressure gradient and the resulting difference between temperature and streamwise velocity around the vortex.

最近的研究表明，旋风涡与背景剪切具有相同的符号涡，可以导致不同的传热增强，即比动量传递更多的传热。但是，还不知道气旋涡旋如何达到异样，或者其他类型的涡旋是否也会导致异样。为了解决这些问题，我们在各种条件下将直线涡流管引入层状库埃特流中，并对其中的热和动量传递进行了数值研究。相异性的基本过程是从现实流动的复杂成分中分离出来的，以考虑涡旋与背景切变的相互作用。发现引入了强的展向反旋风涡旋，该旋涡旋涡与背景剪切的旋涡相反。由于与背景气流的长期相互作用，与已知的旋风涡旋相比，可以实现更多的不同传热，而翼展方向旋风旋涡在其时间演化的早期阶段则实现了更大的相异性。通过解释流向压力梯度的分布以及围绕涡流的温度与流向速度之间的差异，阐明了由于这些涡流而引起的相异性的物理机制。