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

13

SAE INTERNATIONAL

DRIVAER

• Comparison of 2nd order accuracy (top) with former 1st

order (bottom) results

Shape Optimisation

14

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