Cp	Specific heat at constant pressure (J/kg·K)
d	Dimensionless opening width
g	Gravitational acceleration (m/s2)
h	Dimensionless opening length, h’/l’
k	Thermal conductivity (W/m·K)
l	Dimensionless cavity width
Nu	Local Nusselt number
Nuav	Average Nusselt number
Pr	Prandtl number
Ra	Rayleigh number
t	Dimensionless time ($t^{\prime }\times \alpha /l^2$)
T	Dimensionless temperature [$(T^{\prime }-{T^{\prime }}_c)/({T^{\prime }}_h-{T^{\prime }}_c)]$
${T^{\prime }}_c$	Cold temperature (K)
${T^{\prime }}_h$	Hot temperature (K)
$\overrightarrow{V}$	Dimensionless velocity vector (${\overrightarrow{V}}^{\prime }·l/\alpha$)
x, y, z	Dimensionless Cartesian coordinates ($x^{\prime }/l$, $y^{\prime }/l$, $z^{\prime }/l$)
Greek Symbols
$\alpha$	Thermal diffusivity (m2/s)
$\beta$	Thermal expansion coefficient (1/K)
$\rho$	Density (kg/m3)
$\mu$	Dynamic viscosity (kg/m·s)
$\nu$	Kinematic viscosity (m2/s)
$\overrightarrow{\psi }$	Dimensionless vector potential ($\overrightarrow{\psi }\prime /\alpha$)
$\overrightarrow{\omega }$	Dimensionless vorticity (${\overrightarrow{\omega }}^{\prime }\times \alpha /l^2$)
$\Delta T$	Dimensionless temperature difference
Subscripts
av	Average
x, y, z	Cartesian coordinates