\expandafter\ifx\csname doTocEntry\endcsname\relax \expandafter\endinput\fi
\doTocEntry\tocchapter{1}{\csname a:TocLink\endcsname{2}{x2-10001}{QQ2-2-1}{Introduction}}{4}\relax 
\doTocEntry\tocsection{1.1}{\csname a:TocLink\endcsname{2}{x2-20001.1}{QQ2-2-2}{Goals}}{5}\relax 
\doTocEntry\tocchapter{2}{\csname a:TocLink\endcsname{3}{x3-30002}{QQ2-3-3}{NACA wing}}{8}\relax 
\doTocEntry\toclof{2.1}{\csname a:TocLink\endcsname{3}{x3-30061}{}{\ignorespaces Visualisation of streamwise velocity field at $t=2.5$.}}{figure}\relax