Table 1.

Grid independency study for $Ri=1,N=3$, and $\varphi =1$.

Mesh size	Mesh elements	Boundary elements	$N{u}_{avg}$	Percentage error $\left(\text{\%}\right)$
Normal	1540	130	9.1572
Fine	2280	160	9.4310	2.9
Finer	5155	285	9.6738	2.5
Extra fine	13653	551	10.580	9.3
Extremely fine	18881	551	10.576	0.03