a	length of triangular wave (m)
b	height of triangular wave (m)
B${}_0$	magnetic field strength
Da	Darcy number, $\frac{\kappa }{H^2}$
Gr	Grashof number, $\frac{g{\beta }_f(T_h-T_c{H}^3}{{\nu }_f^2}$
h	local heat transfer coefficient (W/m${}^2$K)
Ha	Hartmann number, $B_{0}H\sqrt{\frac{{\sigma }_{nf}}{{\rho }_{nf}{\nu }_f}}$
k	thermal conductivity (W/m·K)
H	length of the enclosure (m)
n	unit normal vector
Nu	local Nusselt number
p	pressure (Pa)
P	non-dimensional pressure
Pr	Prandtl number, $\frac{{\nu }_f}{{\alpha }_f}$
T	temperature (K)
u, v	x-y velocity components (m/s)
U, V	dimensionless velocity components
x, y	Cartesian coordinates (m)
X, Y	dimensionless coordinates
Greek characters:
$\alpha$	thermal diffusivity (m${}^2$/s)
$\beta$	expansion coefficient (1/K)
$\varphi$	nanoparticle volume fraction
$\theta$	non-dimensional temperature,
$\frac{\mathit{T}-{\mathit{T}}_{\mathit{c}}}{{\mathit{T}}_{\mathit{h}}-{\mathit{T}}_{\mathit{c}}}$
$\nu$	kinematic viscosity (m${}^2$/s)
$\rho$	density of the fluid (kg/m${}^3$)
$\sigma$	electrical conductivity (S/m)
Subscripts:
c	cold wall
m	average
h	hot wall