|
[Sponsors] |
What does 2D laminar model for turbulent flow imply? |
![]() |
|
LinkBack | Thread Tools | Search this Thread | Display Modes |
![]() |
![]() |
#1 |
New Member
Yu Wang
Join Date: Sep 2021
Posts: 3
Rep Power: 4 ![]() |
I know that laminar model is solving Navier-Stokes equations without any averaging. For 3D simulation, transient analysis of laminar model with time averaging and very fine mesh should give the result similar to that of turbulence modeling with relatively coarser mesh. Since turbulence is inherently 3D, then for a flow with high enough Reynolds number, does a 2D transient analysis of laminar model with very fine mesh and time averaging give the result similar to that obtained by turbulence modeling? Can the 2D laminar model give the correct turbulence velocity profile in the boundary layer?
|
|
![]() |
![]() |
![]() |
![]() |
#2 | |
Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,830
Rep Power: 73 ![]() ![]() ![]() |
Quote:
|
||
![]() |
![]() |
![]() |
![]() |
#3 |
New Member
Yu Wang
Join Date: Sep 2021
Posts: 3
Rep Power: 4 ![]() |
Let me clarify, if I use 2D laminar model for mid-to-high Reynolds flow problem, even though I get convergence and grid-independence, that still means its the wrong result and wouldn't exactly correspond to real world physics? If so, then for 2D model, is it based on user's experience to choose the right model? for example, the user should only use laminar model for very low Reynolds flow (Re<2000) in which based on user's experience for that particular flow problem has definitely no turbulence and if somehow there is some turbulence in the real world version of the same problem, then the results from the 2D laminar model are not correct? Does this mean that, for a 2D problem, I should always use turbulence model for the flow problem which I am not sure is completely laminar?
|
|
![]() |
![]() |
![]() |
![]() |
#4 | |
Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,830
Rep Power: 73 ![]() ![]() ![]() |
Quote:
2D laminar model only for: - low Re flow - LES/DNS of geophysical flows (with some care) You can use 2D model for turbulence only for steady RANS. |
||
![]() |
![]() |
![]() |
![]() |
#5 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,728
Rep Power: 66 ![]() ![]() ![]() |
Note that 2D model even for laminar flows can still be wrong because of the same vortex stretching mechanism being missing. Laminar flows can also have vortexes.
Getting any solution, whether this be numerical, analytical, or even experimental, its merit is judged based not only on the tools and methods used but also the hypothesis it is trying to assess. Getting an exact solution to a Schrodinger equation for example doesn't help you do fluids. |
|
![]() |
![]() |
![]() |
Tags |
turbulence and laminar |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
unable to run dynamic mesh(6dof) and wave UDF | shedo | Fluent UDF and Scheme Programming | 0 | July 1, 2022 17:22 |
Laminar model solves seemingly turbulent flow | nmartin9319 | Main CFD Forum | 4 | August 10, 2018 11:33 |
Wrong flow in ratating domain problem | Sanyo | CFX | 17 | August 15, 2015 06:20 |
Using a turbulent model when the flow is entirely laminar. | mwhyte | FLUENT | 1 | June 7, 2012 10:35 |
Laminar flow in species transport model? | Neha Rao | FLUENT | 7 | February 25, 2006 02:23 |