SimCafe

Space shortcuts

Child pages
  • FLUENT - Unsteady Flow Past a Cylinder - Step 5

Versions Compared

Old Version 78

changes.mady.by.user user-8c4ec

Saved on

compared with

New Version Current

changes.mady.by.user user-8c4ec

Saved on

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.
Comment: Migration of unmigrated content due to installation of a new plugin

...

Info
titleCalculating Time Step Size

The Strouhal number for flow past cylinder is roughly 0.183 as reported by Williamson .
In order to capture the shedding correctly, we should have at least 20 to 25 time steps in one shedding cycle. Let's use 25 for our case.

{} \large $$ {\rm{Sr}} = {fD \over U} = 0.183 $$ {latex}
Wiki Markup
Latex
For our case, D = 2, U = 1 
 Therefore, shedding frequency f = 0.0915 
 Cycle time,
unmigrated-inline-wiki-markup
{}
\large
$$
{\rm{t}} = {1 \over f} = 10.9 sec
$$
{latex}
 Latex
Therefore, Time Step Size = 10.9/25 = 0.436 sec ~ 0.4 sec
...