How to impose Deforming Wall Boundary Condition in CFX ?

xq712000 · July 22, 2016, 08:55

Hello everyone,

I want to run a transient simulation of an airplane wing flow.

The most important feature is that I want the wing surface deform according to a user defined function

This is a one-way fluid-structure interaction (FSI) problem, but from structure to fluid.

I have heard that this can be done throng PROFILE DATA, but I don't know the details...OTZ

Can anyone present some instructions ? and suggestions ?

Best Wishes

ghorrocks · July 22, 2016, 18:33

FSI is normally where a CFD solver gives the fluid flow and resulting forces, and those forces are given to an FEA solver to solve the displacements. You appear to be doing the displsacements yourself, so this is not a normal FSI simulation.

I would recommend doing this as a moving mesh simulation, and you put your displacement function in as the mesh movement. (And no, profile data will not be useful for this. You cannot do it that way).

xq712000 · July 25, 2016, 10:10

Actually, there is a bit more information behind this problem...

I'm planning to build a Reduced-Order Model (ROM) of aerodynamic forces based on System Identification techniques

What I need to do is to identify the functional relation between forced motions ( structure's surface nodal displacements as input signal ) and aerodynamic forces as output signal.
And, the aerodynamic forces need to be transformed to nodal forces on the structure's surface nodes...

It's actually easy to do a two-way FSI simulation using CFX coupled with Transient Structure
And, the distributed aerodynamic forces on the wing surface must be able to transformed to structure's surface nodal forces ( to couple with Transient Structure analysis )

I have a strong sense that two-way FSI simulation, such as CFX coupled with Transient Structure, could be modified to do a one-way FSI simulation, from structure to fluid
And that the structure's surface node displacements could be represent by modal superposition

I wonder if this is possible...and how can I make it happen...
and I'm totally unfamiliar with the commands...

can I have some more specific guides ...?

Best Wishes

July 22, 2016, 08:55	How to impose Deforming Wall Boundary Condition in CFX ?	#1
xq712000 New Member XieQing Join Date: Mar 2013 Location: Capital of Qin Dynasty Posts: 22 Rep Power: 13	Hello everyone, I want to run a transient simulation of an airplane wing flow. The most important feature is that I want the wing surface deform according to a user defined function This is a one-way fluid-structure interaction (FSI) problem, but from structure to fluid. I have heard that this can be done throng PROFILE DATA, but I don't know the details...OTZ Can anyone present some instructions ? and suggestions ? Best Wishes

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July 22, 2016, 18:33		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,705 Rep Power: 143	FSI is normally where a CFD solver gives the fluid flow and resulting forces, and those forces are given to an FEA solver to solve the displacements. You appear to be doing the displsacements yourself, so this is not a normal FSI simulation. I would recommend doing this as a moving mesh simulation, and you put your displacement function in as the mesh movement. (And no, profile data will not be useful for this. You cannot do it that way).

July 25, 2016, 10:10		#3
xq712000 New Member XieQing Join Date: Mar 2013 Location: Capital of Qin Dynasty Posts: 22 Rep Power: 13	Actually, there is a bit more information behind this problem... I'm planning to build a Reduced-Order Model (ROM) of aerodynamic forces based on System Identification techniques What I need to do is to identify the functional relation between forced motions ( structure's surface nodal displacements as input signal ) and aerodynamic forces as output signal. And, the aerodynamic forces need to be transformed to nodal forces on the structure's surface nodes... It's actually easy to do a two-way FSI simulation using CFX coupled with Transient Structure And, the distributed aerodynamic forces on the wing surface must be able to transformed to structure's surface nodal forces ( to couple with Transient Structure analysis ) I have a strong sense that two-way FSI simulation, such as CFX coupled with Transient Structure, could be modified to do a one-way FSI simulation, from structure to fluid And that the structure's surface node displacements could be represent by modal superposition I wonder if this is possible...and how can I make it happen... and I'm totally unfamiliar with the commands... can I have some more specific guides ...? Best Wishes