Skip to content
Snippets Groups Projects
Commit e6528523 authored by Florian Atteneder's avatar Florian Atteneder
Browse files

fix more typos; realize that the spherical accretion initial data likely does...

fix more typos; realize that the spherical accretion initial data likely does not satisfy the geometric constraints
parent b29902a8
No related branches found
No related tags found
No related merge requests found
......@@ -1639,8 +1639,7 @@ The 3+1 decomposition of the metric yields
\end{align}
in particular, the shift vector $\beta^\mu$ does not vanish in this case.
For the evaluation of the source terms in the GRHD equations we need the following
quantities
For the evaluation of the source terms in the GRHD equations we need the following quantities
\begin{align}
T^{tt} &= h \rho (u^t)^2 - (\frac{2M}{r} + 1) p \, ,
&
......@@ -1651,9 +1650,9 @@ quantities
T^{\theta\theta} &= \sin(\theta)^2 T^{\phi\phi} = \frac{p}{r^2} \, .
\end{align}
\begin{align}
K_{rr} &= \frac{2M(M+r)}{\sqrt{r^5( 2M+r )}} \, ,
K_{rr} &= -\frac{2M(M+r)}{\sqrt{r^5( 2M+r )}} \, ,
&
K_{\theta\theta} &= \frac{K_{\varphi\varphi}}{\sin(\theta)^2} = - 2M \sqrt{\frac{r}{2M+r}} \, ,
K_{\theta\theta} &= \frac{K_{\varphi\varphi}}{\sin(\theta)^2} = 2M \sqrt{\frac{r}{2M+r}} \, ,
\end{align}
\begin{align}
\tensor{\hGa}{^r_r_r} &= - \frac{M}{r(2M+r)} \, ,
......@@ -1669,6 +1668,7 @@ quantities
\tensor{\hGa}{^\phi_\theta_\phi} &= \frac{\cos(\theta)}{\sin(\theta)} \, ,
\end{align}
where $\tensor{\hGa}{^i_j_k}$ are the Christoffels of the induced metric $\tensor{\hat{\gamma}}{_i_j}$.
The expression for the extrinsic curvature is also given in \cite[Table 2.1]{baumgarte2010}.
For the choice of reference metric and conformal metric we use
$\tensor{\gamma}{_i_j} = \tensor{\bar{\gamma}}{_i_j} = \tensor{\hat{\gamma}}{_i_j}$,
......@@ -1681,13 +1681,21 @@ with $\vec{g}^{i}, \vec{r}$ being the SRHD values.
\detail{
Here follow unnecessary details which I wrote down before I realized the following:
The initial data construction for this test, outlined in \autoref{ssec:spherical-accretion},
assumes the Schwarzschild solution as a fixed background spacetime.
Consequently, the geometric constraint equations need not be satisfied, because the
Schwarzschild solution is a solution to the vacuum EFEs.
Nevertheless, it is possible to have a stationary or static state solution in the hydro
sector only.
To evaluate the geometric constraints we need to compute the following values too,
\begin{align}
\partial_r K_{rr} &= \frac{2M}{\sqrt{r^5(2M+r)}} - \frac{5M(M+r)}{\sqrt{r^7(2M+r)}} - \frac{M(M+r)}{\sqrt{r^5(2M+r)^3}} \, ,
\\
\partial_r K_{\theta\theta} &= \partial_r \frac{K_{\phi\phi}}{\sin(\theta)^2} =
- \frac{M}{\sqrt{r(2M+r)}} + M \sqrt{\frac{r}{(2M+r)^3}} \, ,
\\
\partial_r K_{rr} &= \frac{2M(5M^2+2r^2+6Mr)}{\sqrt{r^7(2M+r)^3}} \, ,
&
\partial_r K_{\theta\theta} &= \partial_r \frac{K_{\phi\phi}}{\sin(\theta)^2} = \frac{2M^2}{\sqrt{r(2M+r)^3}} \, ,
&
\partial_\theta \tensor{K}{_\phi_\phi} \sim \cos(\theta) &\xrightarrow{\theta = \pi/2} 0 \, ,
\end{align}
......@@ -1756,7 +1764,7 @@ With this we can evaluate the $r$ component of the momentum constraint
\begin{align}
D_j (K^{rj} - \gamma^{rj} K) = 8\pi S^r \, .
\end{align}
}
......@@ -1991,6 +1999,7 @@ computed in the following references
\subsubsection{Spherical accretion}
\label{ssec:spherical-accretion}
The construction of the initial data is discussed in \cite[section 4.2]{bugner2015} and
......
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment