update: auto commit
This commit is contained in:
+9
-11
@@ -12,8 +12,6 @@
|
||||
|
||||
\usepackage{appendixnumberbeamer}
|
||||
|
||||
\newcommand{\Schwarzschild}{Schwarzschild}
|
||||
|
||||
\tikzset{zigzag/.style={decorate, decoration=zigzag}}
|
||||
\def \L {2.}
|
||||
|
||||
@@ -295,7 +293,7 @@
|
||||
|
||||
|
||||
\begin{frame}{Methods on evolving black holes: moving puncture}
|
||||
In the isotropic coordinate for \Schwarzschild{} black hole, the spacial metric
|
||||
In the isotropic coordinate for Schwarzschild black hole, the spatial metric
|
||||
\begin{equation}
|
||||
\dd{l^2} = \left( 1+\frac{M}{2r} \right)^4 (\dd{r^2} + r^2 \dd{\Omega^2})
|
||||
\end{equation}
|
||||
@@ -313,7 +311,7 @@
|
||||
|
||||
\begin{frame}{Methods on evolving black holes: moving puncture}
|
||||
|
||||
In the moving puncture mothod, we won't cut out the black hole singularity, but choose a gauge condition that makes the singularity invisible to the numerical evolution.
|
||||
In the moving puncture method, we won't cut out the black hole singularity, but choose a gauge condition that makes the singularity invisible to the numerical evolution.
|
||||
\begin{figure}
|
||||
\centering
|
||||
\includegraphics[width=0.7\textwidth, trim=4bp 4bp 4bp 4bp, clip]{imgs/moving_puncture_penrose_1.png}
|
||||
@@ -354,7 +352,7 @@
|
||||
\begin{equation}
|
||||
\left(v_a, \pdvt{u}\right) + \left(v_a, A^i \pdv{u}{x^i}\right) = (v_a, S),
|
||||
\end{equation}
|
||||
which reduce to a linear system of $\{ u_a = (v_a, u)\}$ after intergrating by parts. Boundary terms are replaced by numerical fluxes.
|
||||
which reduce to a linear system of $\{ u_a = (v_a, u)\}$ after integrating by parts. Boundary terms are replaced by numerical fluxes.
|
||||
|
||||
In \texttt{nmesh}, we use Lagrange polynomials over Gauss-Legendre points on each element.
|
||||
\begin{center}
|
||||
@@ -465,7 +463,7 @@
|
||||
\vspace{-0.5cm}
|
||||
\begin{itemize}
|
||||
\item Z4 and GH evolve the physical metric, and thus not compatible with the moving puncture method.
|
||||
\item The rests are using the conformal metric.
|
||||
\item The rests use the conformal metric.
|
||||
\begin{itemize}
|
||||
\item Z4c damps the constraints better than BSSN, as the constraint violations propagate at the speed of light and thus move out.
|
||||
\item Unstable in CCZ4 for black hole spacetime was reported with some parameters.
|
||||
@@ -527,7 +525,7 @@
|
||||
\begin{itemize}
|
||||
\item GH
|
||||
\begin{itemize}
|
||||
\item Not compatible with moving puncture mothod
|
||||
\item Not compatible with moving puncture method
|
||||
\end{itemize}
|
||||
\item FOCCZ4
|
||||
\begin{itemize}
|
||||
@@ -712,7 +710,7 @@ $}
|
||||
\dsmetric*{_i_j_k} \definedby \Partial{_i} \smetric*{_j_k},
|
||||
$}
|
||||
\]
|
||||
and replace all the spatical derivatives of the original variables with the new auxiliary variables, we got this
|
||||
and replace all the spatial derivatives of the original variables with the new auxiliary variables, we got this
|
||||
\[
|
||||
\scalebox{0.47}{$\displaystyle
|
||||
\begin{aligned}
|
||||
@@ -859,18 +857,18 @@ $}
|
||||
Another way to speed up is, maybe we can start from FOCCZ4:
|
||||
\begin{itemize}
|
||||
\item FOCCZ4 is already strongly hyperbolic
|
||||
\item FOCCZ4 only differs from our naive first order reduction of Z4c by some constraint terms, to be specific, sone terms proportional to $\tensor{\tilde{Z}}{^i}$ or it's derivatives. We can remove these differing terms and watch how the hyperbolicity changes, and find out how to recover the hyperbolicity
|
||||
\item FOCCZ4 only differs from our naive first order reduction of Z4c by some constraint terms, to be specific, some terms proportional to $\tensor{\tilde{Z}}{^i}$ or it's derivatives. We can remove these differing terms and watch how the hyperbolicity changes, and find out how to recover the hyperbolicity
|
||||
\item We also add constraint damping terms, which will break the hyperbolicity, and then find out how to recover the hyperbolicity.
|
||||
\end{itemize}
|
||||
|
||||
In short, we are looking for a series of hyprbolicity-preserving modifications to FOCCZ4, to get a first order reduction of Z4c with constraint damping. This is working in progress.
|
||||
In short, we are looking for a series of hyperbolicity-preserving modifications to FOCCZ4, to get a first order reduction of Z4c with constraint damping. This is working in progress.
|
||||
\end{frame}
|
||||
|
||||
\begin{frame}{Searching for a first order Z4c}{Current status}
|
||||
\begin{itemize}
|
||||
\item What we have:
|
||||
\begin{itemize}
|
||||
\item A mathematica note book that takes readable tensor equations as input, and automatically computes the principal symbol matrix
|
||||
\item A Mathematica notebook that takes readable tensor equations as input, and automatically computes the principal symbol matrix
|
||||
\end{itemize}
|
||||
\item What we are doing:
|
||||
\begin{itemize}
|
||||
|
||||
Reference in New Issue
Block a user