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update theory doc
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juddmehr committed Jun 27, 2024
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18 changes: 18 additions & 0 deletions docs/src/DuctAPE/theory_latex/customcommands.tex
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Expand Up @@ -602,3 +602,21 @@ \section*{Chapter~\thechapter~Appendices}

%%%%% ------ allow newlines inside table cells with the \makecell{} environment
\usepackage{makecell}


% fancy table alignment
\usepackage{array}
\newcommand{\PreserveBackslash}[1]{\let\temp=\\#1\let\\=\temp}
\newcolumntype{C}[1]{>{\PreserveBackslash\centering}m{#1}}
\newcolumntype{R}[1]{>{\PreserveBackslash\raggedleft}m{#1}}

\usepackage{multirow}
\usepackage{array, makecell}
\renewcommand\theadfont{}
\renewcommand\theadalign{tc}
\renewcommand\cellalign{tr}
\setcellgapes{5pt}
\newcolumntype{/}{!{\color{plotsgray!50}\vrule width 0.001pt}}

% decimal aligned columns in table
\usepackage{siunitx} % for 'S' column type
2 changes: 1 addition & 1 deletion docs/src/DuctAPE/theory_latex/ductape.tex
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Expand Up @@ -12,7 +12,7 @@ \chapter{DuctAPE Theory}

\input{ductpostprocessing}

\input{ductsolveralgorithm}
\input{ductverification}

% %%% --- Chapter Appendices --- %%%
\clearpage
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23 changes: 4 additions & 19 deletions docs/src/DuctAPE/theory_latex/ductbodymethods.tex
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Expand Up @@ -225,7 +225,7 @@ \subsubsection{Discretizing bodies into panels}
%
\Cref{fig:flatbandgeometry} shows what is intended by a flat, axisymmetric band, and \cref{fig:flatpanelgeometry} shows the panel representation of said band.

\begin{figure}[htb]
\begin{figure}[h!]
\centering
\begin{subfigure}[t]{0.45\textwidth}
\centering
Expand Down Expand Up @@ -329,28 +329,13 @@ \subsubsection{Calculating Panel Induced Velocities}

Because the surface integrals of velocities induced by axisymmetric vortex rings are exceptionally difficult to solve analytically, we will take a numerical approach.
%
Specifically, we will utilize Gauss-Kronrod quadrature via the QuadGK.jl\sidenote{\url{https://juliamath.github.io/QuadGK.jl/stable/gauss-kronrod/}}
package in the Julia\scite{Julia_2017} language.
%
In general, quadrature is the process of approximating an integral of a function using a sum of weighted samples of the function:

\begin{equation}
\int_a^b f(x) \d x \approx \sum_k^N w_k f(x_k),
\end{equation}

\where the main task of the setup is to decide where along the integration interval to place the sample points, \(x_k\), and what weights, \(w_k\), to apply to those samples.
%
Gauss-Kronrod quadrature is based on Gauss-Legendre quadrature, which uses orthogonal polynomial theory to select sample points and weights that allow for exact integration of polynomials up to degree \(2N-1\) (where \(N\) is the number of sample points), and other sufficiently smooth functions remarkably well.
%
Despite being based on Gauss-Legendre quadrature, however, Gauss-Kronrod quadrature is not quite as accurate as pure Gauss-Legendre quadrature in a one-to-one comparison.
%
Gauss-Kronrod quadrature can exactly integrate polynomials up to \(3N+1\) for \(2N+1\) sample points.
%
The decrease in accuracy for the same conditions is the trade off required to be able to both calculate the integral approximation and the error in the integral approximation.
%
The ability to quickly estimate error directly leads to capabilities for \(h\)-adaptive quadrature, which is an adaptive method that refines the integration range along portions that require further refinement for accuracy (such as sharp peaks, or perhaps discontinuities).
%
So although not as accurate out of the box, obtaining more accurate integrals over domains that would be difficult for pure Gauss-Legendre quadrature becomes relatively simple, and a worthwhile trade.

In the nominal case when a panel induces velocity on the surface, but not on itself, we set things up as follows for a given panel and surface point, \(t\):
%
Expand Down Expand Up @@ -1393,7 +1378,7 @@ \subsubsection{Multi-body System Verification}
%
We now place both in a single system in order to verify that multi-body systems work properly.

\begin{figure}[hb!]
\begin{figure}[h!]
\centering
\input{figures/duct-and-hub-validation-geom.tikz}%
\caption{Isolated duct and center body geometry together.}
Expand All @@ -1402,7 +1387,7 @@ \subsubsection{Multi-body System Verification}
%
As can be seen in \cref{fig:dfdclewiscomp}, the surface velocity on the hub and pressure on the duct match very well to DFDC, lending confidence in DuctAPE's ability to model both a duct and hub together.

\begin{figure}[htb]
\begin{figure}[h!]
\centering
\begin{subfigure}[b]{0.45\textwidth}
\raggedright
Expand Down Expand Up @@ -1435,7 +1420,7 @@ \subsubsection{Multi-body System Verification}
%
We see in \cref{fig:dfdcexamplecomp} that DuctAPE also matches well with DFDC in this case.

\begin{figure}[htb]
\begin{figure}[h!]
\centering
\begin{subfigure}[b]{0.45\textwidth}
\raggedright
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8 changes: 5 additions & 3 deletions docs/src/DuctAPE/theory_latex/ductintro.tex
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Expand Up @@ -5,7 +5,7 @@ \section{Introduction}
%
It may also be desirable to sacrifice some flexibility to further decrease computation time costs in the beginning stages of design.
%
To this end, a low-fidelity tool for the evaluation of ducted propulsors, catered specifically to electric ducted fans, is described in this chapter.
To this end, a low-fidelity tool for the evaluation of ducted propulsors, catered specifically to electric ducted fans, is described in this document.
%
One of the major limitations in flexibility is that we require that:

Expand All @@ -24,11 +24,13 @@ \section{Introduction}

\end{assumption}

\noindent Therefore, we call our tool Ducted Axisymmetric Propulsor Evaluation, or DuctAPE for short.
\noindent Therefore, we call our tool \textbf{Duct}ed \textbf{A}xisymmetric \textbf{P}ropulsor \textbf{E}valuation, or DuctAPE for short.
%
We also required a steady-state assumption, meaning the solution is stationary in time.
%
As alluded to, the overall goal of DuctAPE is to provide a computationally inexpensive tool to be used in a multidisciplinary design and optimization setting for preliminary and conceptual design.

In this chapter we cover the methodology derivation required for DuctAPE as well as some implementation details and various verification and validation along the way.
In this document we cover the methodology derivation required for DuctAPE as well as some implementation details and various verification and validation along the way.
%
The solver is comprised of two major components, which will be first presented in isolation before the full coupling is considered.
%
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11 changes: 4 additions & 7 deletions docs/src/DuctAPE/theory_latex/ductrotorwakemethods.tex
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Expand Up @@ -298,7 +298,7 @@ \subsubsection{Rotor Profile Drag}
%
\Cref{fig:rvf_eif} shows visually this concept.
%
\begin{figure}[htb]
\begin{figure}[h!]
\centering
\begin{subfigure}[t]{0.45\textwidth}
\centering
Expand Down Expand Up @@ -488,7 +488,7 @@ \subsection{Wake Model}
h_B \approx \frac{2\pi}{B} \left(\frac{W_m}{-W_\theta}\right).
\end{equation}

\begin{figure}[htb]
\begin{figure}[h!]
\centering
\begin{subfigure}[t]{0.45\textwidth}
\centering
Expand Down Expand Up @@ -1674,9 +1674,6 @@ \subsubsection{Elliptic Wake Grid}
%
In contrast to the centerbody trailing edge panel, we only apply the vorticity portion of the wake panel strength based on the last wake node along the streamline.

\subsubsection{Solution Approach:}
re-write


\subsection{Verification and Validation of Isolated Rotor+Wake Aerodynamics}
\label{ssec:rwvv}
Expand All @@ -1696,7 +1693,7 @@ \subsubsection{Verification of Induced Velocities}
Note that the swirl velocity as modeled in DuctAPE is zero upstream of the rotor, and the far-field value at any point aft of the rotor as described by \cref{eqn:vtheta,eqn:vthetaself}.


\begin{figure}[htb]
\begin{figure}[h!]
\centering
\begin{subfigure}[t]{0.45\textwidth}
\centering
Expand Down Expand Up @@ -1724,7 +1721,7 @@ \subsubsection{Validation of Thrust and Power Coefficients}
%
As can be seen in \cref{fig:rotval1}, DuctAPE matches well with BEMT, and both are within expectations when compared to experimental data.

\begin{figure}[htb]
\begin{figure}[h!]
\centering
\begin{subfigure}[t]{0.45\textwidth}
\centering
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