CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

Problem with vortex shedding frequency

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 26, 2014, 08:31
Default Problem with vortex shedding frequency
  #1
New Member
 
Saravana Kumar Lakshmanan
Join Date: Feb 2013
Posts: 11
Rep Power: 10
aerosaravanan is on a distinguished road
Hi friends,
I am currently trying to simulate flow past a circular cylinder for my thesis in OpenFOAM. I am having problem in getting the correct strouhal number. Drag coefficient is comparatively good. The following are the BCs and details about mesh


Dia=0.034 m; velocity=20 m/s; Re=45,000 ; Solver- PISOFOAM; RANS Model-kOmegaSST


P-freestreamPressure at inlet & outlet, zeroGradient on cylinder (wall), Symmetry on Top & Bottom


U-freeStreamVelocity at inlet & outlet, fixedValue (0) on wall, Symmetry on Top & Bottom


k-fixedValue at inlet (based on k=3/2(UI)^2),zerogradient at outlet, FixedValue (0) on wall and kqrwallfunction, Symmetry on Top & Bottom


omega-fixedvalue at inlet & outlet (based on omega=k^3/2/kcmul) basically took from one journal paper.For wall omega wall function and value =60nu/betaXdely^2. Symmetry for Top & Bottom


nut-fixedvalue(0) at inlet, zerogradient at outlet,nutuspaladingwallfunction on wall, symmetry on Top and bottom.


Mesh details:
Y+=1, Four meshes are tested 50K,65K,80K,and 95K with max aspect ratio less than 22. The domain size is sufficiently long was used.
fvSchmes:


Time- Euler, gradschmes-Gauss linear, Divergence-Gauss limitedlinear,Laplacian-Gauss linear corrected
Interpolation-linear, Sngrad-corrected


Fvsolution:
PCG with DIC as preconditioner for pressure with tolerance of 1e-06, reltol=0
For other terms PBiCG with DILU ,tolerance 1e-08


Ncorrectors=2,northogonalcorrectors=3


Please help me to solve this friends, Hope I described all important details
aerosaravanan is offline   Reply With Quote

Old   November 19, 2020, 19:35
Default
  #2
Member
 
Chris Harding
Join Date: Dec 2016
Posts: 75
Rep Power: 6
HappyS5 is on a distinguished road
Hello,

I wish I could help you, but I cannot.

I am working on a tutorial that requires that the Strouhal Number be calculated and compared to literature. How did you calculate the frequency that is used to calculate the Strouhal Number?

I appreciate any assistance you might have.
HappyS5 is offline   Reply With Quote

Old   November 20, 2020, 06:16
Default
  #3
Senior Member
 
Santiago Lopez Castano
Join Date: Nov 2012
Posts: 317
Rep Power: 12
Santiago is on a distinguished road
Quote:
Originally Posted by aerosaravanan View Post
Hi friends,
I am currently trying to simulate flow past a circular cylinder for my thesis in OpenFOAM. I am having problem in getting the correct strouhal number. Drag coefficient is comparatively good. The following are the BCs and details about mesh


Dia=0.034 m; velocity=20 m/s; Re=45,000 ; Solver- PISOFOAM; RANS Model-kOmegaSST


P-freestreamPressure at inlet & outlet, zeroGradient on cylinder (wall), Symmetry on Top & Bottom


U-freeStreamVelocity at inlet & outlet, fixedValue (0) on wall, Symmetry on Top & Bottom


k-fixedValue at inlet (based on k=3/2(UI)^2),zerogradient at outlet, FixedValue (0) on wall and kqrwallfunction, Symmetry on Top & Bottom


omega-fixedvalue at inlet & outlet (based on omega=k^3/2/kcmul) basically took from one journal paper.For wall omega wall function and value =60nu/betaXdely^2. Symmetry for Top & Bottom


nut-fixedvalue(0) at inlet, zerogradient at outlet,nutuspaladingwallfunction on wall, symmetry on Top and bottom.


Mesh details:
Y+=1, Four meshes are tested 50K,65K,80K,and 95K with max aspect ratio less than 22. The domain size is sufficiently long was used.
fvSchmes:


Time- Euler, gradschmes-Gauss linear, Divergence-Gauss limitedlinear,Laplacian-Gauss linear corrected
Interpolation-linear, Sngrad-corrected


Fvsolution:
PCG with DIC as preconditioner for pressure with tolerance of 1e-06, reltol=0
For other terms PBiCG with DILU ,tolerance 1e-08


Ncorrectors=2,northogonalcorrectors=3


Please help me to solve this friends, Hope I described all important details
What is the maxCourant?
Santiago is offline   Reply With Quote

Reply

Tags
cylinder, komegasst, pisofoam, shedding

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Which Foam for vortex shedding problem Madeleine P. Vincent OpenFOAM 7 November 20, 2018 06:31
Vortex shedding comparing tools Apocolapse STAR-CCM+ 0 February 25, 2012 08:52
Vortex shedding? rbel038 CFX 4 April 27, 2008 19:57
vortex shedding not captured Deloat CFX 6 February 28, 2008 04:25
Shedding Frequency Oliver Main CFD Forum 2 September 5, 2000 07:40


All times are GMT -4. The time now is 15:13.