CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > FLUENT

flow over cylinder

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

Reply
 
LinkBack Thread Tools Display Modes
Old   November 21, 2008, 03:27
Default flow over cylinder
  #1
pang
Guest
 
Posts: n/a
Hi All,

i doing a 'CFD simulation of Riser VIV'. i started it with very simple things first just like flow(water)over a cylinder in order to obtain drag coefficient using Fluent 6.1. i have try many time but the solution is not converge!may i know which setting is wrong?

first i used this link to calculated my cell height: http://geolab.larc.nasa.gov/APPS/Yplus/ with Re=500000,Y+=3, charac length=1 so my calculated ds=0.0000875 Meter

then i used the ds value as my first length when doing meshing in Gambit

After that i start to run my fluent with below setting Solverressure based viscous model: Spalart-Allmaras Spalart-Allmaras option=strain/vorticity based production material:water-liquid Operatin pressure=101325

For my velocity Inlet boundary condition: velocity Spec Method= Component (is this option correct?) X velocity= 0.5 Y velocity= 0(because i intend to start with simple flow which only have x direction flow). Turbulence Spec. Method=Modified Turbulence Viscosity (is this correct? or should i choose other?if yes, why) Modified Turbulence Viscosity=0.001 (this is default value,is it correct? or elso how to calculate?)

For my pressure outlet boundary condition: gauge Pressure= 0 Backflow direction Spec. Method:= Normal to boundary Turbulence Spec. Method= Modified Turbulence Viscosity (is this correct? or should i choose other?if yes, why) Modified Turbulence Viscosity=0.001 (this is default value,is it correct? or elso how to calculate?)

Solution Control: Pressure=Standard Pressure-velocity coupling=simple Momentum=Second order upwind Modified Turbulence Viscosity=second order upwind

Residuals Monitor Convergence criterio=1e-06

Force Monitor: Coeefficient=Drag Force vector,X=1 Force vector,Y=0

then i make sure my Report>reference value is same as my previous input before i start the iteration

i run until 10000 iteration n yet it converge Can anybody help me to solve it? i may send you my meshing file if needed. Thank a lot!

  Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Flow in cylinder andesameer OpenFOAM Running, Solving & CFD 1 February 25, 2009 07:06
Flow over a flat plate & Flow over a cylinder cfdxue Main CFD Forum 0 November 27, 2007 00:26
Flow over a cylinder taran FLUENT 4 July 17, 2007 15:15
Flow behind a cylinder Vasily FLUENT 3 October 30, 2003 18:34
flow around cylinder kchoukairy Main CFD Forum 1 June 12, 2002 08:31


All times are GMT -4. The time now is 20:51.