Table 1.

Grid sensitivity checks: ${\mathrm{\Psi }}_{\min }$, ${\overline{\mathit{Nu}}}_{\mathit{nf}}$ and ${\overline{\mathit{Nu}}}_s$ for $Ra={10}^6$, $H=10$, $B=0.5$, $Da={10}^{-3}$, $\varphi =0.02$, $N=2$, $\gamma =10$, $D=0.5$.

Size of grid	# of elements	${\mathrm{\Psi }}_{\min }$	${\overline{\mathit{Nu}}}_{\mathit{nf}}$	${\overline{\mathit{Nu}}}_s$
G1	2971	$-2.5253$	3.9993	2.9993
G2	3403	$-2.5422$	4.0531	3.0531
G3	3909	$-2.5707$	4.0668	3.0668
G4	4810	$-2.59014$	4.1051	3.1051
G5	11794	$-2.6276$	4.2542	3.2542
G6	27151	$-2.6407$	4.2552	3.2552
G7	32745	$-2.6443$	4.2562	3.2562