107 lines
4 KiB
TeX
107 lines
4 KiB
TeX
\chapter{OlaFlow}
|
|
|
|
\section{2D Model}
|
|
A 2Dv model was built on a small domain around the breakwater (\SI{250}{\m}
|
|
from the crest).
|
|
|
|
A tool that allows mapping the output fields from swash to the initial fields
|
|
in olaFlow was built. Alpha.water and U fields are mapped from swash to
|
|
olaFlow.
|
|
|
|
Boundary conditions are set using the output from the swash model.
|
|
|
|
A regular mesh is generated and snapped to the bathymetry (mesh resolution: \SI{.5}{\m}).
|
|
|
|
Simulation is run for 400 seconds using the largest wave from the swash model with the buoy spectrum as an input
|
|
(\autoref{fig:wave}).
|
|
|
|
\begin{figure}
|
|
\centering
|
|
\includegraphics{wave.pdf}
|
|
\caption{Boundary condition for olaflow model.}\label{fig:wave}
|
|
\end{figure}
|
|
|
|
Results are plotted using python \autoref{fig:resola}.
|
|
\begin{figure}
|
|
\centering
|
|
\includegraphics{resola.pdf}
|
|
\caption{Results from olaFlow model.}\label{fig:resola}
|
|
\end{figure}
|
|
|
|
\subsection{Porosity parameters}
|
|
Several parameters should be calibrated in order to accurately model the porous media: $a$, $b$ and $c$ are friction
|
|
parameters in Forcheimer's equation; D50 is the median diameter of the elements constituting the porous media; $p$ is
|
|
the porosity of the media.
|
|
|
|
7 cases were run with the values in \autoref{tab:porotest}.
|
|
|
|
\begin{table}
|
|
\centering
|
|
\begin{tabular}{cccccc}
|
|
\toprule
|
|
\textbf{Case} & $a$ & $b$ & $c$ & D50 (\si{\m}) & $\phi$ \\
|
|
\midrule
|
|
\textbf{0} & \num{50} & \num{1.2} & \num{0.34} & \num{4} & \num{0.4} \\
|
|
\textbf{1} & \intersemibold\num{0} & \num{1.2} & \num{0.34} & \num{4} & \num{0.4} \\
|
|
\textbf{2} & \intersemibold\num{5000} & \num{1.2} & \num{0.34} & \num{4} & \num{0.4} \\
|
|
\textbf{3} & \num{50} & \intersemibold\num{0} & \num{0.34} & \num{4} & \num{0.4} \\
|
|
\textbf{4} & \num{50} & \intersemibold\num{3.0} & \num{0.34} & \num{4} & \num{0.4} \\
|
|
\textbf{5} & \num{50} & \num{1.2} & \num{0.34} & \intersemibold\num{2} & \num{0.4} \\
|
|
\textbf{6} & \num{50} & \num{1.2} & \num{0.34} & \num{4} & \intersemibold\num{0.25} \\
|
|
\bottomrule
|
|
\end{tabular}
|
|
\caption{Test cases for porosity parameters.}\label{tab:porotest}
|
|
\end{table}
|
|
|
|
Some results are displayed in \autoref{fig:diff} and \autoref{fig:diff2}. No major differences are noticable
|
|
between cases (excepted for case 3, where $b=0$).
|
|
|
|
\begin{figure}
|
|
\centering
|
|
\includegraphics{diff.pdf}
|
|
\caption{Tests for porosity parameters; water - air border at \SI{-50}{\m}.}\label{fig:diff}
|
|
\end{figure}
|
|
\begin{figure}
|
|
\centering
|
|
\includegraphics{diff2.pdf}
|
|
\caption{Tests for porosity parameters; water - air border at \SI{-20}{\m}.}\label{fig:diff2}
|
|
\end{figure}
|
|
|
|
Another run with a different value for $b$ was made (\autoref{tab:porotestb}). Results are in \autoref{fig:diff3b}.
|
|
The value of $b$ seems to have a major effect how wave energy is dissipated / how waves break, as seen in
|
|
\autoref{fig:diff3b175}.
|
|
|
|
\begin{table}
|
|
\centering
|
|
\begin{tabular}{cccccc}
|
|
\toprule
|
|
\textbf{Case} & $a$ & $b$ & $c$ & D50 (\si{\m}) & $\phi$ \\
|
|
\midrule
|
|
\textbf{0} & \num{50} & \num{1.2} & \num{0.34} & \num{4} & \num{0.4} \\
|
|
\textbf{1} & \num{50} & \intersemibold\num{0} & \num{0.34} & \num{4} & \num{0.4} \\ % 3
|
|
\textbf{2} & \num{50} & \intersemibold\num{0.2} & \num{0.34} & \num{4} & \num{0.4} \\ % 3b
|
|
\bottomrule
|
|
\end{tabular}
|
|
\caption{Test cases for porosity parameters.}\label{tab:porotestb}
|
|
\end{table}
|
|
|
|
\begin{figure}
|
|
\centering
|
|
\includegraphics{diff3b.pdf}
|
|
\caption{Tests for porosity parameters; water - air border at \SI{-20}{\m}.}\label{fig:diff3b}
|
|
\end{figure}
|
|
\begin{figure}
|
|
\centering
|
|
\includegraphics{diff3b175.pdf}
|
|
\caption{Tests for porosity parameters; water - air border at \SI{175}{\s}.}\label{fig:diff3b175}
|
|
\end{figure}
|
|
|
|
\subsection{Turbulence model}
|
|
A case with the $k-\omega$ SST turbulence model was run to compare with the $k-\varepsilon$ model.
|
|
Results displayed in \autoref{fig:sst}. Significant differences are found between both models.
|
|
|
|
\begin{figure}
|
|
\centering
|
|
\includegraphics{diffsst.pdf}
|
|
\caption{Case 1: $k-\varepsilon$ model; case 2: $k-\omega$ SST model.}\label{fig:sst}
|
|
\end{figure}
|