As the ANSYS FLUENT Theory guide mentioned, there exists a transition of Turbulent Viscosity Ratio from the minimun to the maximum and then back to the minor value again, however, in my simulation ( a circular tube with diameter of 10mm and inlet velocity of 10m/s, the fluid flow is air under the standard condition, it's obvious that the flow is turbulent), the transition phenomenon does not appear, but with the a trend of inreasing from the minimum at the near all region to the maximum in the tube center. So, can someone please explain what's wrong with my simulation ?
BEST REGARDS
Hi R. Wally,
There is no problem with your simulation. The text you highlighted is related to the boundary layer in external flows. In internal flows, two boundary layers reach together at the tube center, and in that area, the maximum turbulent viscosity occurs.
The fluid which flows is air, so the velocity has big values in the cross section at your diameter. The turbulent zone is very extended to the walls. I am sure that your Reynolds number has a very big value, so the velocity distribution in the cross section is almost uniform, like for an ideal fluid. It appears normal that nothing special happends.
- Badges
- Science topic