Anemometer plan view.

\begin{figure}[htbp] \begin{center}
\mbox{
\subfigure[Case 1] {
\def\subfigcapskip{300pt}
\def\farskip{200pt}
\begin{tikzpicture} [scale=0.6]
\draw (0,0) circle (2.5cm); % anemometer body, top down.
\draw (120:1.1) circle (0.9cm) node {$a$};
\draw (0:1.1) circle (0.9cm) node {$b$}; % polar coordinates!
\draw (240:1.1) circle (0.9cm) node {$c$};
\draw [white] (5,-3); % forcing space below subfigure
\draw[->] (-5,0) -- node [above] {flow} (-3,0) ;

% Support pillars
\foreach \x in {0 + 30, 60 + 30, 120 + 30, 180 + 30, 240 + 30, 300 + 30}
\draw (\x-3:2.5) -- (\x-3:2.5-0.25) -- (\x + 3:2.5-0.25) -- (\x+3:2.5);

\end{tikzpicture} }

\subfigure[Case 2] {
\def\subfigcapskip{300pt}
\def\farskip{200pt}
\begin{tikzpicture} [scale=0.6]
\draw (0,0) circle (2.5cm); % anemometer body, top down.
\draw (120+30:1.1) circle (0.9cm) node {$a$};
\draw (0+30:1.1) circle (0.9cm) node {$b$}; % polar coordinates!
\draw (240 + 30:1.1) circle (0.9cm) node {$c$};
\draw [white] (0,-3); % forcing space below subfiure

% Support pillars
\foreach \x in {0 + 60, 60 + 60, 120 + 60, 180 + 60, 240 + 60, 300 + 60}
\draw (\x-3:2.5) -- (\x-3:2.5-0.25) -- (\x + 3:2.5-0.25) -- (\x+3:2.5);

\end{tikzpicture} } }
\caption{Orientation of the anemometer with respect to flow direction, for the
two experiments.}
\label{fig:TwoMeasurements}
\end{center}
\end{figure}