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

1-way time step problem in doing FSI between Fluent and Transient Structural

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 21, 2013, 03:45
Default 1-way time step problem in doing FSI between Fluent and Transient Structural
  #1
Senior Member
 
starter
Join Date: Sep 2012
Posts: 125
Rep Power: 16
sihaqqi is on a distinguished road
I am having this strange error in Ansys during FSI. I am using Fluent and Transient Structural. Main source of error occurs in Analysis settings while defining time steps. When I run in Fluent for initial time step of 0.0001 and final step of 0.1s, and import loads in transient using WB, the Analysis settings in transient structural wants to have final time of value of 1. Though this shall never be the case but for the purpose of testing, when I run Fluent for time steps finishing at 5 seconds, it again gives the message "Time specified for an imported load does not match any of the step end times. Please enter a valid time value so that imported time match as step end time". Either I use 1 as the last time step or somewhere in the middle does it solve my problem but due to this reason I do not know if it is evaluating for time steps after 1 as well. It only solves with extremely large displacements for time value of 1 and due to this lot of non-convergence is happening as it starts giving me erroneous results. I have visited this link http://www.eureka.im/4470.html which tells the method to address this situation but when I open this file, all values that I get are 1 at the place in the file mentioned. I have attached this file for review. Also it is giving me some errors which I cannot understand but if this issue can be resolved, there is a possibility that all the other issues will fade away as they may be generated as a result of this. My final settings for extremely fine mesh shall be 0.15 at very best. If I have to increase the time step to 1 in Fluent, my calculation time will increase drastically as both geometries I have to evaluate are very big.

I have to extract Mode shapes out of transient and transient does not connect to Modal for individual pipe sections.
Please advise.

Regards
sihaqqi is offline   Reply With Quote

Reply

Tags
fsi


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
How to determine time step size and Max. iterations per time step. pratik c FLUENT 46 January 21, 2024 13:21
number of iterations per time step chouki FLUENT 1 August 13, 2013 01:11
Transient flow in fluent linyx FLUENT 15 April 24, 2013 10:54
Time accuracy of NITA - FRACTIONAL STEP in Fluent Paolo Lampitella Main CFD Forum 0 March 19, 2008 08:20
unsteady calcs in FLUENT Sanjay Padhiar Main CFD Forum 1 March 31, 1999 13:32


All times are GMT -4. The time now is 15:51.