Abstract: We established a twodimensional numerical model and comparatively investigated the impact of heating wall on vortex shedding of microcylinders with different diameters of 2 cm, 20 μm and 2 μm for low Reynolds number (0~100). We further addressed the cause and influence of diameter, wall and fluid temperature difference on vortex growth and shedding law, velocity at wake region, temperature field and distribution of vortex street parameters.We also fitted the quantitative relationship between Strouhal number and low Reynolds number.We found that vortices street of a microcylinder at wake region appeared much earlier than that of a conventionsized cylinder when its diameter reduced to 2 μm. However, heating wall reduced the discrepancies among the cylinders with three different diameters and made the appearance of the lowest Re all less than 40 for the vortex street at leeward region. The ratio of row distance h to line distance l of vortex street increased with the increase of temperature difference between the wall and the fluid, but the ratio of vortex street at wake region of different diameter cylinders decreased with the increase of Re for identical temperature difference. The ratio significantly increased with the decrease of the diameter of microcylinders for identical Re. Sr of a microcylinder with heating wall was greater than that without heating wall, the biggest discrepancy of 20% available.

Key words: microcylinder, heating wall, numerical simulation, vortex shedding