\begin{figure}
   \begin{tikzpicture}[scale=1.6, spy using outlines={circle, magnification=4, size=3cm, connect spies}]
   \node[anchor=south,inner sep=0] {\includegraphics[height=80mm,clip=true,trim=105mm 0mm 50mm 0mm]%,frame]
    {figures/figure16/{liquidfractioncolouredbytemperature_cooledinlets}.jpg}\label{fig:16:a}};
   \node[anchor=north,inner sep=0] {\includegraphics[height=80mm,clip=true,trim=115mm 0mm 50mm 0mm]%,frame]
    {figures/figure16/{liquidfractioncolouredbytemperature_cooledcore}.jpg}\label{fig:16:b}};
   \spy [black] on (-1.15,-4.1) in node at (2.5,-0.5); 
  \end{tikzpicture}
 \caption[
Temperature fields for 3D coupled flow and heat transfer cases at different wall temperatures with frozen salt films. Upper: Cooled core inlets after \SI{26.5}{\second} of simulation time; Lower: Core cooled up to a core radius of \SI{1.6}{\metre} after \SI{17.7}{\second} of simulation time; Thick black arrows indicate flow direction. The zoomed circle indicates the region where a hot spot forms and the salt is molten in the location of the white cells.
]{}
\label{fig:16} % second figure in \S\,\ref{casestud:07} 
\end{figure}
