|
[Sponsors] |
December 8, 2018, 09:43 |
Reverse flow
|
#1 |
New Member
Greece
Join Date: May 2017
Posts: 20
Rep Power: 8 |
Hi guys
i am analyzing a 3d hydrofoil in ansys fluent 19.2 academic and for somw reason after 20 iterations i am getting the message of reverse flow in xxx faces in pressure outlet 6 I ve tried every solution available like changing from pressure outlet to outflow or mass outflow or even i ve tried to move outlet further away from the airfoil (right now my chord is 1m and the domain is 10m ) i ve tried to change the model ( i am using SST k-omega) but the message remains. I have even placed gauge pressure at the outlet in order to suck out any turbulence causing the reverse flow but nothing. I dont know if this is the main issue but the solution after one point does not converge and goes high up. (pictures attached) Any opinion on the matter? |
|
December 8, 2018, 10:54 |
|
#2 |
Member
subhankar das
Join Date: Jul 2018
Posts: 32
Rep Power: 7 |
Can you show residual image?
|
|
December 8, 2018, 11:35 |
|
#3 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,674
Rep Power: 65 |
These are common warnings and not necessarily anything going wrong here. The only real issue is the solution not converging after 10000 iterations.
It's either your boundary conditions are completely wrong, your initialization was crap, or your mesh is absolute garbage. I would investigate in that order. You could also remove the airfoil, try just a box to see if you can get a result with this simple setup. Build up some experience. |
|
December 8, 2018, 12:33 |
|
#4 | |
New Member
Greece
Join Date: May 2017
Posts: 20
Rep Power: 8 |
Quote:
finally me solution converged somehow but the reverse flow problem remains, My mesh is fine and i think the boundary are also fine as shown in the pictures attached. I get the cl=1.65 cd=0.3 at 8 degrees.. Is that ok for a naca0012? |
||
December 8, 2018, 12:37 |
|
#5 |
New Member
Greece
Join Date: May 2017
Posts: 20
Rep Power: 8 |
hi sir
here are the residuals you ve asked Thank you in advance |
|
December 10, 2018, 14:07 |
|
#6 |
Member
Piotr Prusinski
Join Date: Oct 2009
Location: Warsaw, Poland
Posts: 67
Rep Power: 16 |
Sorry for asking silly (little off-topic) questions, but is the idea behind meshing the airfoil itself?
BTW. I see some inconsitencies: 1) In the velocity-inlet, you set 4 m/s while in the initialization it is given 2 m/s 2) The backflow my came also due to pair of inlet-outlet conditions. Try pressure-inlet and pressure-outlet (or far-field if it still exists). /Piotrek |
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Solution is converging but have reverse flow on pressure outlet | Dinesh_Dhande | Main CFD Forum | 2 | March 11, 2018 01:02 |
Reverse flow at the outlet | Mohammad80 | FLUENT | 0 | March 30, 2016 04:31 |
Reverse flow at boundary | andyross33 | CFX | 2 | August 27, 2013 13:24 |
Flow simulation in reverse drum mixer | Patel Chirag | CFX | 0 | July 19, 2010 15:05 |
Reverse flow in the VOF model | yan | FLUENT | 1 | May 26, 2005 09:14 |