results

tex/main.tex

@@ -9,7 +9,8 @@
 \textinput{reynold}
 \section{Results}
 \textinput{steady-state}
-\textinput{diagrams}
+\textinput{unsteadystate}
+% \textinput{diagrams}
 % \begin{appendices}
   % \textinput{some-appendix-section}
 % \end{appendices}

tex/steady-state.tex

@@ -3,7 +3,7 @@
 \input{.maindir/tex/header/preamble-section}
 % inputs the preamble only if necessary
 \docStart
-\subsection{Steady state}
+\subsection{Steady state} \label{sec:steady}
 The configuration with $\Rey = 20$ and $\bar u = \SI{0.2}{\metre\per\second}$ results in a steady state.
 After a very short time (\SI{0.6}{\second}) of adjusting, the flow reaches a situation that (almost) does not change anymore. Hence only the first $2$ instead of $20$ seconds were calculated.
 
@@ -23,7 +23,7 @@ The calculations were performed with $N = 6$ ($1728$ cells), $6$ correctors, $2$
 \end{figure}
 In figure \ref{fig:steadystate} we can see the recirculation zone with a length of approximately \SIrange{15}{20}{\centi\metre}.
 Here I take the area where the flow is disturbed, hence not a straight flow as the recirculation zone.
-In the literature the length of the recirculation is zone is about \SI{8}{\centimetre},
+In the literature the length of the recirculation is zone is about \SI{8}{\centi\metre},
 about half of my value.
 But the paper does not define what this zone is, hence those values are not comparable.
 
@@ -34,7 +34,7 @@ The captions include the comparison with the literature.
   \tikzinput{bothpressures}
   \caption{Pressure in front and behind the cylinder and the difference.
     The pressure difference quickly steadies at \SI{0.5}{\square\metre\per\square\second}.
-    In the literature, the pressure difference is in most cases about \num{0.1}{\square\metre\per\second} which is a fifth of my value.
+    In the literature, the pressure difference is in most cases about \SI{0.1}{\square\metre\per\second} which is a fifth of my value.
   }
 \label{fig:steadyP}
 \end{figure}

tex/unsteadystate.tex

+%! TEX program = lualatex
+
+\input{.maindir/tex/header/preamble-section}
+% inputs the preamble only if necessary
+\docStart
+\subsection{Unsteady state}
+The literature claims that at a Reynolds number of $\Rey = 100$ ($\bar u = \SI{1}{\metre\per\second}$) the flow becomes unsteady.
+
+My experiments did not support this claim.
+With $u = \SI{1}{\metre\per\second}$ a steady state is reached before \SI{0.86}{\second}.
+This steady state can be seen in figure \ref{fig:unsteady}.
+\begin{figure}[htpb]
+  \centering
+  \newcommand{\picwidth}{0.95\linewidth}
+  \includegraphics[width=\picwidth]{.maindir/zeichnungen/100_u_x}
+  \includegraphics[width=\picwidth]{.maindir/zeichnungen/100_u_y}
+  \includegraphics[width=\picwidth]{.maindir/zeichnungen/100_p}
+  \caption{The steady state is reached at time \SI{0.6}{\second}.
+    Those images are from $t ="\SI{0.86}{\second}$.
+    From top to bottom we have the velocity in flow direction,
+    the velocity perpendicular to it and the pressure.%
+  }
+  \label{fig:steadystate}
+\end{figure}
+
+The recirculation zone in this case is approximately \SIrange{25}{30}{\centi\metre} long.
+The same uncertainty as in section \ref{sec:steady} applies.
+
+The pressure values in front and behind the cylinder and the coefficiants are plotted in  the figures \ref{fig:unsteadyP}, \ref{fig:unsteadyCd} and \ref{fig:unsteadyCl}.
+The captions include the comparison with the literature.
+\begin{figure}[ht]
+  \centering
+  \tikzinput{unsteady_bothpressures}
+  \caption{Pressure in front and behind the cylinder and the difference.
+    The pressure difference quickly steadies at \SI{3.85}{\square\metre\per\square\second}.
+    In the literature, the pressure difference is in most cases about \SI{2.4}{\square\metre\per\second} which are two thirds of my value.
+  }
+  \label{fig:unsteadyP}
+\end{figure}
+\begin{figure}[ht]
+  \centering
+  \tikzinput{unsteady_Cd}
+  \caption{The drag coefficiant over time. It steadies at \num{219.5}.
+    In the literature $C_{D\max}$ is about \num{3.2} which is about \SI{1.5}{\percent} of my value but it is a maximum value.
+  }
+  \label{fig:unsteadyCd}
+\end{figure}
+\begin{figure}[ht]
+  \centering
+  \tikzinput{unsteady_Cl}
+  \caption{The lift coefficiant over time. It steadies at \num{2.68}.
+    In the literature $C_{L\max}$ is about \num{1} which is about \SI{40}{\percent} of my value.
+  }
+  \label{fig:unsteadyCl}
+\end{figure}
+
+The comparisons to the literature indicate that there is a major flaw in the setup.
+In particular I cannot see a turbulent flow and therefore a Strouhal number cannot be calculated.
+\docEnd