Gambit/Fluent: Stress free boundary conditions

plmatthews · October 5, 2010, 04:44

Hi,

I have created a simple 2-d mesh of a moutain bike helmet which is basically a half circle at the bottom of a large rectangle (a circle subtracted from a rectangle). I have been told I need to specify stress free boundary conditions for the bottom edge (infront and behind the helmet) I can not find stress free conditions in the 'type' drop down box on the 'specifiy boundary types' menu, can anyone help?

Also as I am using the fluent5/6 solver on gambit there is no inflow on the same drop down menu should I select velocity_inlet or mass_flow_inlet? I pressumed velocity inlet as I will be simulating air flow over the helmet.

Many thanks!

plmatthews · October 7, 2010, 08:13

Please help?!

I basically just need to know how to impose stress-free boundary conditons to a mesh boundary using Gambit 2.2.30 or Fluent 6.2.16 software. :-)

Logan Page · October 8, 2010, 05:57

from what i understand of your problem you can try using a symmetry BC on the bottom edge (front and back)

October 5, 2010, 04:44	Gambit/Fluent: Stress free boundary conditions	#1
plmatthews New Member Join Date: Oct 2010 Posts: 2 Rep Power: 0	Hi, I have created a simple 2-d mesh of a moutain bike helmet which is basically a half circle at the bottom of a large rectangle (a circle subtracted from a rectangle). I have been told I need to specify stress free boundary conditions for the bottom edge (infront and behind the helmet) I can not find stress free conditions in the 'type' drop down box on the 'specifiy boundary types' menu, can anyone help? Also as I am using the fluent5/6 solver on gambit there is no inflow on the same drop down menu should I select velocity_inlet or mass_flow_inlet? I pressumed velocity inlet as I will be simulating air flow over the helmet. Many thanks!

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October 7, 2010, 08:13		#2
plmatthews New Member Join Date: Oct 2010 Posts: 2 Rep Power: 0	Please help?! I basically just need to know how to impose stress-free boundary conditons to a mesh boundary using Gambit 2.2.30 or Fluent 6.2.16 software. :-)

October 8, 2010, 05:57		#3
Logan Page Member Logan Page Join Date: Sep 2010 Posts: 38 Rep Power: 15	from what i understand of your problem you can try using a symmetry BC on the bottom edge (front and back)