The publisher apologises that upon publication of this article a typographical error was introduced with [-4pt] being added to equation 2.1.
The equation should read:
(2.1)
\begin{equation}\left.
\begin{gathered} {\dfrac{{\partial
{u_i}}}{{\partial {x_i}}} = 0,}\\ {\dfrac{{\partial
{u_i}}}{{\partial t}} + \dfrac{{\partial
{u_i}{u_j}}}{{\partial {x_j}}} ={-} \dfrac{{\partial
p}}{{\partial {x_i}}} +
\dfrac{1}{{Re}}\dfrac{{{\partial^2}{u_i}}}{{\partial
{x_j}\partial {x_j}}},}\\ {\dfrac{{\partial \theta
}}{{\partial t}} + \dfrac{{\partial \theta
{u_j}}}{{\partial {x_j}}} =
\dfrac{1}{{ReSc}}\dfrac{{{\partial^2}\theta }}{{\partial
{x_j}\partial {x_j}}}.} \end{gathered}
\right\}\end{equation}