# Page History

## Key

• This line was removed.
• Formatting was changed.

HTML
<div style="background-color: yellow; border: 2px solid red; margin: 4px; padding: 2px; font-weight: bold; text-align: center;">
<br>
Click in the link above if you are not automatically redirected in 10 seconds.
</div>
<meta http-equiv="refresh" content="10; URL='https://courses.ansys.com/index.php/courses/unsteady-flow-past-a-cylinder/'" />

Include Page
Include Page
 Unsteady Flow Past a Cylinder - Panel Unsteady Flow Past a Cylinder - Panel

# Unsteady Flow Past a Cylinder

...

Compared to the steady case, the unsteady case includes an additional time-derivative term in the Navier-Stokes equations:

{latex}
Wiki Markup
Latex
\begin{eqnarray}
\frac{\partial \vec{u}}{\partial t} + \rho (\vec{u}\cdot \triangledown)\vec{u} = -\triangledown p + \mu \triangledown^{2} \vec{u}
\end{eqnarray}
{latex}

The methods implemented by FLUENT to solve a time dependent system are very similar to those used in a steady-state case.  In this case, the domain and boundary conditions will be the same as the Steady Flow Past a Cylinder.  However, because this is a transient system, initial conditions at t=0 are required.  To solve the system, we need to input the desired time range and time step into FLUENT.  The program will then compute a solution for the first time step, iterating until convergence or a limit of iterations is reached, then will proceed to the next time step, "marching" through time until the end time is reached.

Go to Step 1: Pre-Analysis & Start-Up

...