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sihaqqi November 21, 2013 03:45

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


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