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Biblio: Reformat

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\chapter{Literature Review}
In this chapter, literature relevant to the present study will be reviewed.
Three sections will be detailled: the separation of incident and reflected
components from wave measurements, the modelisation of wave impacts on a
@ -6,22 +7,26 @@ rubble-mound breakwater, and the modelisation of block displacement by wave
impacts.
\section{Separating incident and reflected components from wave buoy data}
\subsection{Introduction}
The separation of incident and reflected waves is a crucial step in numerically
modeling a sea state. Using the raw data from a buoy as the input of a wave
model will lead to incorrect results in the domain as the flow velocity at the
boundary will not be correctly generated.
Several methods exist to extract incident and reflected components in measured
sea states,
and they can generally be categorised in two types of methods: array methods
and PUV methods \parencite{inch2016accurate}. Array methods rely on the use of
multiple measurement points of water level to extracted the incident and
reflected waves, while PUV methods use co-located pressure and velocity
measurements to separate incident and reflected components of the signal.
sea states, and they can generally be categorised in two types of methods:
array methods and PUV methods \parencite{inch2016accurate}. Array methods rely
on the use of multiple measurement points of water level to extracted the
incident and reflected waves, while PUV methods use co-located pressure and
velocity measurements to separate incident and reflected components of the
signal.
\subsection{Array methods}
\subsubsection{2-point methods}
Array methods were developped as a way to isolate incident and reflected wave
components using multiple wave records.
\textcite{goda1977estimation,morden1977decomposition} used two wave gauges
@ -42,17 +47,19 @@ the wave environment is that wave frequencies are not modified by the
reflection process.
\subsubsection{3-point methods}
In order to alleviate the limitations from the 2-point methods,
\textcite{mansard1980measurement} introduced a 3-point method. The addition of
a supplementary measurement point along with the use of a least-squares method
most importantly provided less sensitivity to
noise, non-linear interactions, and probe spacing. The admissible frequency
range could also be widened. A similar method was proposed by
\textcite{gaillard1980}. The accuracy of the method for the estimation of
incident and reflected wave components was once again highlighted, while the
importance of adequate positioning of the gauges was still noted.
most importantly provided less sensitivity to noise, non-linear interactions,
and probe spacing. The admissible frequency range could also be widened. A
similar method was proposed by \textcite{gaillard1980}. The accuracy of the
method for the estimation of incident and reflected wave components was once
again highlighted, while the importance of adequate positioning of the gauges
was still noted.
\subsubsection{Time-domain method}
\textcite{frigaard1995time} presented a time-domain method for reflected and
incident wave separation. This method, called SIRW method, used discrete
filters to extract the incident component of an irregular wave field. The
@ -72,6 +79,7 @@ cases. The presented method could also be extended to three-dimensionnal waves
and bathymetry by considering the influence of refraction.
\subsubsection{Further improvements}
Further additions were made to array methods. \textcite{suh2001separation}
developped a method taking constant current into account to separate incident
and reflected waves. This method relies on two or more gauges, using a least
@ -90,17 +98,18 @@ non-linear waves, but are expected to be unreliable in the case of steep
seabeds, as shoaling is not part of the underlying model.
\subsubsection{Conclusion}
Array methods have been developped enough to provide accurate results in a wide
range of situations. Sensibility to noise has been reduced, and the influence
of shoaling has been considered. Those methods can also be applied to irregular
non-linear waves.
However, they require at least two wave gauges to be used.
That means that in some situations such as the Saint-Jean-de-Luz event of 2017,
other methods are needed since only one field measurement location is
available.
However, they require at least two wave gauges to be used. That means that in
some situations such as the Saint-Jean-de-Luz event of 2017, other methods are
needed since only one field measurement location is available.
\subsection{PUV methods}
The goal of PUV methods is to decompose the wave field into incident and
reflected waves using co-located wave elevation and flow velocity measurements
\parencite{tatavarti1989incoming}. \textcite{tatavarti1989incoming} presented a
@ -118,8 +127,9 @@ quasi-nonlinear approach gave the most accurate results.
%\textcite{walton1992} applied a separation method based on co-located pressure
%and velocity measurements on field, studying two natural beaches. This study
%showed that reflection is not significant on natural beaches. Additionnaly, the
%method that is used allowed for larger reflected energy than incident energy.
%showed that reflection is not significant on natural beaches. Additionnaly,
%the method that is used allowed for larger reflected energy than incident
%energy.
Research by \textcite{hughes1993} showed how co-located horizontal velocity and
vertical velocity (or pressure) sensors can be used to extract incident and
@ -139,11 +149,10 @@ of the sensors, showing that the time delay between sensors leads to a peak in
the reflection coefficient at a frequency related to this time delta.
%%% TODO? %%%
%\begin{itemize}
% \item \cite{sheremet2002observations}:
%\end{itemize}
%\begin{itemize} \item \cite{sheremet2002observations}: \end{itemize}
\subsection{Conclusion}
Numerous methods have been developped in order to separate incident and
reflected components from wave measurements. Array methods rely on the use of
multiple, generally aligned, wave gauges, while PUV methods rely on the use of
@ -162,6 +171,7 @@ breakwater and to separate the incident and reflected wave components from the
measured data.
\section{Modeling wave impact on a breakwater}
\subsection{SPH models}
\subsection{VARANS models}