Thermocapillary instability of self-rewetting films on vertical fibers.

The self-rewetting fluid has a quadratic temperature dependence of surface tension with a well-defined minimum, which is distinct from that of normal fluids whose surface tension decreases linearly with temperature. The instability of a self-rewetting film on a vertical hot or cold fiber is investigated using the long-wave asymptotic model, which discovers that the role of the thermocapillarity varies in three different regimes. In the normal regime, the behavior of this fluid is similar to that of a normal fluid while in another anomalous regime, it shows a reverse feature of instability. It is this reverse behavior that guarantees the potentials of this fluid in heat transfer applications. Transient numerical simulations are also performed to be compared with the linear theory and to explore the saturate states as well as the breakup for this special fluid. Apart from supporting the conclusions obtained in the linear analysis, noticeably, the numerical results predict a flatter saturate shape and a weaker breakup in the anomalous regime. [ABSTRACT FROM AUTHOR]