THE ADJOINT SOLVERAngus Lock, Auto Research Center LLC
Eugene de Villiers, Streamline Solutions LLC
SAE INTERNATIONAL
Features
• Supports incompressible & compressible flows
• 2nd order accuracy
• Turbulence handling:
– Spalart Allmaras, k-eps, frozen turbulence
• MRF and porous media support
• Immersed boundary for interface tracking
• Multi-objective:
– forces & moments, uniformity, pressure loss, massflow split,
swirl, wall shear stress, etc
• No expert knowledge required
Adjoint Solver
2
SAE INTERNATIONAL
Overview
• Specify design space and inlet/outlet interfaces
• Define optimisation objectives
• Run single simulation
• Output optimised shape
Topology Optimisation
3
SAE INTERNATIONAL
Simple Duct
• Topology Optimisation
• Pressure loss minimisation
• Design space with obstacles
Topology Optimisation
4
SAE INTERNATIONAL
Simple Duct
• 50% Pressure Loss improvement
• Optimised shape:
Topology Optimisation
5
SAE INTERNATIONAL
Topology Optimisation
6
SAE INTERNATIONAL
Overview
• Multiple objective Functions employed
– Minimize pressure loss in domain
– Maximize flow uniformity through porous media
– Target flow split through outlets 3x33%
– (Reduce curvature)
– (Reduce volume)
Topology Optimisation
7
SAE INTERNATIONAL
Topology Optimisation
8
SAE INTERNATIONAL
HVAC Duct
• Final shape
• 30% reduction in
pressure loss achieved
• At the cost of
– slightly worse flow
uniformity through the
porous media
– slightly worse flow split
at the three outlets
Topology Optimisation
9
SAE INTERNATIONAL
Open Wheel Race Car
• Generic open wheel car shape
• Thanks to Samuel Silva for providing the model
• Symmetric model
• ~17M cells generated with helyxHexMesh
• RANS simulation
• Spalart Allmaras turbulence model
• Lift and drag force objectives
• Internal porous media uniformity objective
Shape Optimisation
10
SAE INTERNATIONAL
Shape Optimisation
11
SAE INTERNATIONAL
DRIVAER
• Generic car shape based on BMW and Audi cars
• Thanks to TU Munich for providing the geometry*
• Symmetric model
• ~7M cells generated with helyxHexMesh
• RANS simulation
• Spalart Allmaras turbulence model
• Lift and drag force objectives
* A. I. Heft, T. Indinger, N. A. Adams: Introduction of a New Realistic Generic Car Model for Aerodynamic Investigations, SAE
2012 World Congress, April 23-26, 2012, Detroit, Michigan, USA, Paper 2012-01-1068
Shape Optimisation
12
SAE INTERNATIONAL
Shape Optimisation
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SAE INTERNATIONAL
DRIVAER
• Comparison of 2nd order accuracy (top) with former 1st
order (bottom) results
Shape Optimisation
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SAE INTERNATIONAL
DRIVAER
• Comparison of 2nd order accuracy (top) with former 1st
order (bottom) results
Shape Optimisation
15
SAE INTERNATIONAL
Others
• Regional train
• Showing drag surface sensitivities (front of the train on the
right side, rear of the train on the left side).
Shape Optimisation
16
Front/Rear combined
SAE INTERNATIONAL
Future Work
• Integrated surface morphing
• Carat++ plug-in from FEMopt
• Revolutionary FEM based surface
morphing framework
– smart filtering & feature preservation
– proven performance
• Improved immersed boundaries
• Adjoint Turbulence
• Adjoint thermal and species
• Adjoint CHT
Adjoint Solver
17
SAE INTERNATIONAL
Questions?
Paper # (if applicable) 18
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