Aeroelastic Analysis of Bridges
 

Dear friends, I want to analysis the effects of wind flow (with/out turbulence) on bridges such as vortex shedding, galloping, flutter and buffeting. So I would like to know that whether the FLUENT can solve these problem. Thank you very much!

Re: Aeroelastic Analysis of Bridges
 

Hi!!!! Fortunately sometimes someone deals with my problems...I'm actually facing a flutter problem with Fluent about an airplane...Yes you ca do what you want to do, even if it's not so easy...Luca

Re: Aeroelastic Analysis of Bridges
 

Dear sir: Modelling bridges with fluent because of varius type and irregular shapes seams to an ambisous project. Also in bridges wind frequency is most important than drag force and vortex shredding thererfore you can not see any bridges designed aerodynamic. but al bridge designer account for wind frequency and speed. regards

Re: Aeroelastic Analysis of Bridges
 

Dear Mehdi, Thanks for your reply. But I think that in long-span bridges, one of the most important thing is aerodynamic. That is the reason why all cable-based bridges need wind-tunnel experiments which are very costly. Regards

Re: Aeroelastic Analysis of Bridges
 

Dear bridgehl4 :i agree some what with Mehdi Ghoddosy, but i think that ANSIS is the most efficent software to study the flow vibration,and forces on the bridge simultanously which u needed, thanks Eng.khairy-Egypt

Re: Aeroelastic Analysis of Bridges
 

Dear Sir: I th e case of long-span bridges especially cable stated beridges ypu are right. In this bridges because of low natural frequency of structure the frequency is far from common wind frequencies and therefor amplification factor is near 1. However, you have to compute amplification factor in any case first. Wind frequency in any locations differs from another and may be near to your bridge frequency. If the amplification factor is near 1 then account for drag force. However I think solving this problem with fluent is to much time consuming if not impossible. Assume a cable stated bridge with truss beams(that is most pupolar). Assume 300m for each span. then you have size your mesh to be smooth enough to account for truss members(maximum 5m with less than 30cm distance between members); how much nodes you have to use. Can this problem be solved with any computer. In addition must important criteria in this sisuation is bridge periodic vibrations that cause the material to creep and fail. Fluent can not model movement of bridge due to wind or at least vibration. I think you have to find another way to solve your problem. I guess ANSYS could be the way. That was just my idea. wish to be right this time. best regards and good luck.

Re: Aeroelastic Analysis of Bridges
 

Dear Mehdi Ghoddosy, Thank you very much for your detailed reply. I completely agree with you about the bridge problem. I have read an announcement of both FLUENT and ABAQUS that they integrated FSI (Fluid-Structure interaction) in their new version (FLUENT 6.2, ABAQUS 6.5). However, It seems that we need both of it and another third-party software at the same time to solve FSI problems. I do not know how about ANSYS. Anybody knows about FSI problem, please recommend me. Thank you

Re: Aeroelastic Analysis of Bridges
 

Hi, I deal wirt FSI for aeroelastic analysis of a complete airplane (flutter, static aeroelasticity, dynamic response). I use Fluent for the aerodynamic pressure load determination. Then I have my own code (a UDF) to solve structural dynamic (CSD), tp interface structural and CFD meshes and to move the grid in Fluent. So you can avoid using Abaqus or Ansys. In other case you can use MPCCI for abaqus-fluent interface. Luca