updated: spalart allmaras documentation with some verification data

git-svn-id: http://svn.sintef.no/trondheim/IFEM/trunk@1263 e10b68d5-8a6e-419e-a041-bce267b0401d
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akva
2011-10-13 12:55:25 +00:00
committed by Knut Morten Okstad
parent 341fd41ecc
commit cb8cb697c2
10 changed files with 72 additions and 1 deletions

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\documentclass[twoside, 11pt, a4paper]{article}
\usepackage{amsmath,amsfonts,amssymb,graphicx,parskip}
\usepackage[utf8]{inputenc}
\usepackage{subfigure}
\DeclareMathOperator{\eps}{\epsilon}
\newcommand{\dee}{\mathrm{d}}
\title{Spalart-Allmaras turbulence model - SplineFEM implementation}
\title{Spalart-Allmaras turbulence model - IFEM implementation}
\author{Arne Morten Kvarving}
\begin{document}
\maketitle
This document describe the derivation of the weak form, and the associated
Jacobian, for the Spalart-Allmaras turbulence model given in \cite{sa}.
It is implemented in SplineFEM in the SpalartAllmaras
Integrand, see src/Integrands/SpalartAllmaras.h/C, while
you can find a test application (and SIM classes) in Apps/SpalartAllmaras.
\section{Equations}
Initial expression:
\begin{equation}
\frac{\partial\tilde{\nu}}{\partial t} + \mathbf{u}\cdot\nabla\tilde{\nu} = c_{b1}\tilde{S}\tilde{\nu}+\frac{1}{\sigma}\left(\nabla\cdot\left(\nu + \tilde{\nu}\right)\nabla\tilde{\nu} + c_{b2}\left|\nabla\tilde{\nu}\right|^2\right) - c_{w1}f_w\left(\frac{\tilde{\nu}}{d}\right)^2.
@@ -115,6 +119,73 @@ The weak form gives a simple mass term.
\bf Weak form, second term:\rm \\
Straight forward, no integration by parts have to be performed.
\newpage
\section{Verification}
We have performed some verification studies to confirm that the model
The first one is a two-dimensional backward facing step with a sharp step. The grid and
geometry definition can be found in Figure \ref{fig:bfsgrid}.
\begin{figure}[h]
\begin{center}
\includegraphics[width=14cm]{bfs2dgrid}
\end{center}
\caption{The geometry (and) grid used for BFS2D code validation test. The grid consists of 18751 nodes.}
\label{fig:bfsgrid}
\end{figure}
The boundary conditions for the velocity and pressure are given in Figure \ref{fig:bfsupbc}.
\begin{figure}[h]
\begin{center}
\includegraphics[width=14cm]{bfs2dupbc}
\end{center}
\caption{The boundary conditions for the velocity and pressure in the BFS2D code validation test.}
\label{fig:bfsupbc}
\end{figure}
\begin{figure}[h]
\begin{center}
\includegraphics[width=8cm]{inflow}
\end{center}
\caption{The inflow velocity profile.}
\label{fig:bfsinflow}
\end{figure}
The boundary conditions for the turbulent viscosity are given in Figure \ref{fig:bfsnutbc}.
\begin{figure}[h]
\begin{center}
\includegraphics[width=14cm]{bfs2dnutbc}
\end{center}
\caption{The boundary conditions for the turbulent viscosity in the BFS2D code validation test.}
\label{fig:bfsnutbc}
\end{figure}
Some important parameters;
\[
\begin{split}
u_{\infty} &= 1 \\
\nu &= 0.000331 \\
\rho &= 1 \\
Re &= 3025 \\
\Delta t &= 0.005
\end{split}
\]
The following results were obtained using a second order scheme with SUPG stabilization for both the
turbulence model and the velocity solver. No substantial differences compared to the results without
can be observed using the naked eye.
\newpage
\begin{figure}[h]
\begin{center}
\subfigure[$\frac{x}{S}=4$]{\includegraphics[width=5.5cm]{x0}}
\subfigure[$\frac{x}{S}=6$]{\includegraphics[width=5.5cm]{x2}}
\subfigure[$\frac{x}{S}=8$]{\includegraphics[width=5.5cm]{x4}}
\subfigure[$\frac{x}{S}=10$]{\includegraphics[width=5.5cm]{x6}}
\subfigure[$\frac{x}{S}=12$]{\includegraphics[width=5.5cm]{x8}}
\subfigure[$\frac{x}{S}=16$]{\includegraphics[width=5.5cm]{x12}}
\end{center}
\caption{Comparison of velocity profiles.}
\label{fig:bfsx1}
\end{figure}
\end{document}

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