Numerical study of fractal characteristics of heat transfer interface in two-dimensional thermal planer jets

A numerical study of fractal characteristics of heat transfer interface in incompressible two-dimensional thermal planar jets is conducted. The fractal characteristics of heat transfer interface are investigated under three typical Prandtl numbers and two-types of inflow velocity profiles. The results show that heat transfer interface is fractal, and the fractal dimension decreases as the Prandtl number increases. It is caused mainly by the non-negligible effect of rapider development of thermal diffusion than momentum diffusion, which could produce finer structures in lower Pr flows. Moreover, this trend is enhanced by the increased inflow momentum thickness of the jets, as a thicker inflow boundary layer could initiate more space for heat transfer development.