2

I'm trying to generate an aligned pair of equations with the alignat environment. However, I have two major problems:

  1. There is extra horizontal space before my aligned points.
  2. The euqation numbers are far too close to the page margin. I have already searched for a solution online but couldn't find anything that would help. I would really appreciate if somebody has a solution or work-around!

screen output

\begin{alignat}{5}
  & \frac{\partial \rho k}{\partial t} &{}+{}&
  \frac{\partial \rho u_j k}{\partial x_j} &{}={}&
  \tau_{ij} \frac{u_i}{\partial x_j} -
  \beta^* \rho \omega k +
  \frac{\partial \left( \rho \left( \nu + \sigma_k \nu_\text{turb} \right )\frac{\partial k}{\partial x_j} \right )}{\partial x_j}
\\
  & \frac{\partial \rho \omega}{\partial t} &{}+{}&
  \frac{\partial \rho u_j \omega}{\partial x_j} &{}={}&
  \frac{\gamma}{\nu_\text{turb}} {}\tau_{ij} \frac{\partial u_i}{\partial u_j} -
  \beta \rho \omega^2 +
  \frac{\partial \left(\rho \left(\nu + \sigma_\omega \nu_\text{turb} \right ) \frac{\partial \omega}{\partial k} \right )}{\partial x_j}
  \notag
 \\
  & && && + 2 \left(1-F_1 \right ) \frac{\rho \sigma_{\omega2}}{\omega} \frac{\partial k}{\partial x_j}
  \frac{\partial \omega}{\partial x_j}
\end{alignat}
2
  • I get this with your code, and it seems to be okay.
    – user156344
    Apr 10, 2019 at 16:18
  • Welcome to tex.sx. Extra space is added before the relation when you enter it as &{}=; omit the {}. Apr 10, 2019 at 16:30

2 Answers 2

2

I can't reproduce your picture with the code you show.

Anyway, here's a simplified version.

\documentclass{article}
\usepackage{amsmath}

\newcommand{\pder}[2]{\frac{\partial #1}{\partial #2}}

\begin{document}

\begin{alignat}{3}
  & \pder{\rho k}{t} &&+ \pder{\rho u_j k}{x_j} &&=
  \tau_{ij} \frac{u_i}{\partial x_j} -
  \beta^* \rho \omega k +
  \pder{\bigl( \rho (\nu + \sigma_k \nu_{\mathrm{turb}}) \pder{k}{x_j} \bigr)}{x_j}
\\
  & \pder{\rho \omega}{t} &&+
  \pder{\rho u_j \omega}{x_j} &&=
  \frac{\gamma}{\nu_{\mathrm{turb}}} \tau_{ij} \pder{u_i}{u_j} -
  \beta \rho \omega^2 +
  \pder{\bigl(\rho (\nu + \sigma_\omega \nu_{\mathrm{turb}}) \pder{\omega}{k} \bigr)}{x_j}
  \notag
 \\
  & && && \qquad + 2 (1-F_1) \frac{\rho \sigma_{\omega2}}{\omega} \pder{k}{x_j}
  \pder{\omega}{x_j}
\end{alignat}

\end{document}

Note that \nu_\text{turb} is improper, because the word should be upright independently on the font in the surrounding text. Use \nu_{\mathrm{turb}}.

I also simplified the input for partial derivatives, that makes formulas shorter and more readable.

enter image description here

1

Welcome to TeX-SE! With align instead of alignat I get

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{align}
   \frac{\partial \rho k}{\partial t} +
  \frac{\partial \rho u_j k}{\partial x_j} &=
  \tau_{ij} \frac{u_i}{\partial x_j} -
  \beta^* \rho \omega k +
  \frac{\partial \left( \rho \left( \nu + \sigma_k \nu_\text{turb} \right )\frac{\partial k}{\partial x_j} \right )}{\partial x_j}
\\
   \frac{\partial \rho \omega}{\partial t} +
  \frac{\partial \rho u_j \omega}{\partial x_j} &=
  \frac{\gamma}{\nu_\text{turb}} {}\tau_{ij} \frac{\partial u_i}{\partial u_j} -
  \beta \rho \omega^2 +
  \frac{\partial \left(\rho \left(\nu + \sigma_\omega \nu_\text{turb} \right ) \frac{\partial \omega}{\partial k} \right )}{\partial x_j}
  \notag
 \\
  &\hphantom{=} + 2 \left(1-F_1 \right ) \frac{\rho \sigma_{\omega2}}{\omega} \frac{\partial k}{\partial x_j}
  \frac{\partial \omega}{\partial x_j}
\end{align}
\end{document}

enter image description here

1
  • It seems that the OP is trying to align the elements in the left hand side also.
    – user156344
    Apr 10, 2019 at 16:22

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .