www.rbf-morph.com RBF Morph, an ANSYS Inc. Partner 2011 EnginSoft International Conference 20 - 21 October Verona Fluid Structure Interaction (FSI) with RBF Morph Generic Formula 1 Front Wing • Outline • RBF Morph Tool Presentation • Industrial FSI application • Conclusions Dr. Marco Evangelos Biancolini University of Rome “Tor Vergata”
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www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
Fluid Structure Interaction (FSI) with RBF Morph
Generic Formula 1 Front Wing
• Outline
• RBF Morph Tool Presentation
• Industrial FSI application
• Conclusions
Dr. Marco Evangelos Biancolini
University of Rome “Tor Vergata”
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
RBF Morph Tool Presentation
• Morphing & Smoothing
• The Aim of RBF Morph
• RBF Morph Features
• Background
• How It Works
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
Morphing & Smoothing
• A mesh morpher is a tool capable to perform mesh modifications, in order to achieve arbitrary shape changes and related volume smoothing, without changing the mesh topology.
• In general a morphing operation can introduce a reduction of the mesh quality
• A good morpher has to minimize this effect, and maximize the possible shape modifications.
• If mesh quality is well preserved, then using the same mesh structure it’s a clear benefit.
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
The Aim of RBF Morph • The aim of RBF Morph is to perform fast mesh morphing using a mesh-independent
approach based on state-of-the-art RBF (Radial Basis Functions) techniques.
• The use of RBF Morph allows the CFD user to perform shape modifications, compatible with the mesh topology, directly in the solving stage, just adding a single command line in the input file
• The final goal is to perform parametric studies of component shapes and positions typical of the fluid-dynamic design like:
• Add on fully integrated within Fluent (GUI, TUI & solving stage) and Workbench
• Mesh-independent RBF fit used for surface mesh morphing and volume mesh smoothing
• Parallel calculation allows to morph large size models (many millions of cells) in a short time
• Management of every kind of mesh element type (tetrahedral, hexahedral, polyhedral, etc.)
• Support of the CAD re-design of the morphed surfaces
• Multi fit makes the Fluent case truly parametric (only 1 mesh is stored)
• Precision: exact nodal movement and exact feature preservation.
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
Background: RBF Theory • A system of radial functions is used to fit a solution for the
mesh movement/morphing, from a list of source points and their displacements. This approach is valid for both surface shape changes and volume mesh smoothing.
• The RBF problem definition does not depend on the mesh
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• Radial Basis Function interpolation is used to derive the displacement in any location in the space, so it is also available in every grid node.
• An interpolation function composed by a radial basis and a polynomial is defined.
zyxh 431 x
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
How it Works: the work-flow
• RBF Morph basically requires three different steps:
• Step 1 [SERIAL] setup and definition of the problem
(source points and displacements).
• Step 2 [SERIAL] fitting of the RBF system.
• Step 3 [SERIAL or PARALLEL] morphing of the surface
and volume mesh (available also in the CFD solution
stage).
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
How it Works: the problem setup
• The problem must describe correctly the desired changes
and must preserve exactly the fixed part of the mesh.
• The prescription of the source points and their
displacements fully defines the RBF Morph problem.
• The problem is mesh-independent, and could be defined
using grid nodes as well as arbitrary point locations.
• Each problem and its fit define a mesh modifier or a
shape parameter.
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
How it Works: the interface
• One of the key aspects of RBF Morph, in respect to FLUENT
integration, is related to the ability of extracting information from
the FLUENT mesh and to the
user interface GUI
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
Let RBF-Morph talk now!
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
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www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
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www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
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www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
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www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
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www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
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www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
Ge
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www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
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www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
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www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
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www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
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www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
Industrial FSI application
• Challenge
• Test Case Description
• Solution
• Morphing and FSI Set Up
• Results
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
Challenge: Fast FSI Tool.
• CFD calculations are usually performed
considering the undeformed wing
configuration (i.e. rigid parts)
• When important effects are observed (wing
deformation and rotation) the CFD model
should be updated to the deformed
configuration.
• Even a slight deformation can have a
dramatic effect on performances (Drag, Lift,
Tyre-Wing interaction,…).
• A feasible solution is given by Fluent + RBF
Morph: the CFD model parameterized using
modal shapes becomes flexible!
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
Test Case Description: Generic F1 Front End
• Attention is focused on the front wing that is connected to the body by means of two pylons
• The wing is composed by two profiles (Main and an adjustable Flap)
• Transversal flow is confined by the End Plate and a Fence
• Compliance of parts is critical! Loads are very high and even small deflections can affect the wing performance (drag, lift, wing tyre interaction)
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
2011 EnginSoft International Conference
20 - 21 October Verona
Solution: Modes Embedding with RBF Morph
1. Modal shapes are calculated using FEA
2. Fluid mesh is parameterized using modal shapes by RBF Morph each mode is stored as a standard shape modifier
3. fmorph module is initialized at the beginning of CFD parallel run
4. Modal Forces are integrated onto the CFD mesh within Fluent
5. The amplification of each mode is obtained dividing the modal force for the squared circular frequency
6. CFD mesh is updated using known amplifications
7. The CFD model becomes elastic i.e. is capable to update its shape using actual pressure with a single command
8. Usually the shape is updated during CFD iterations (typical updating interval is 25)