where n is the normal direction along the boundary and the characteristic
length S is defined as the perimeter of the circular cylinder
and square enclosure. Table 1 shows the comparisons of
NuMean for different uniform grids with those of Moukalled and
Acharya [11] and Shu et al. [12]. All simulated surface-averaged
Nusselt number are consistent with literature data and the difference
by using the coarse (200 200, 300 300, 400 400) and
finest grids (600 600) are about 0.46%, 0.02% and 0.03%. Therefore,
the uniform grid resolution of 300 300 cells is adopted in the
following simulated cases.
It should be noted that in Refs. [11,12] boundary conforming
grids are adopted. Instead, the present study adopts the immersed
boundary technique to mimic the complex geometry using Cartesian
grid. The present results showgood agreement with the results