How to carry out fundamental research together with industrylada/slides/slides_ffi_april_2019.pdf · 2019-04-04 · APPLIED AND FUNDAMENTAL RESEARCH I will show ﬁve nice examples

HOW TO CARRY OUT FUNDAMENTAL RESEARCH

TOGETHER WITH INDUSTRY

Lars Davidson

Division of Fluid Dynamics

Dept. of Mechanics and Maritime Sciences (M2)

Chalmers

APPLIED AND FUNDAMENTAL RESEARCH

I will show five nice examples of fundamental research carried outtogether with industry

◮ Water droplets/ruvulets on side mirrors◮ Heat transfer in engines: exp & simulation◮ External windnoise disturbing driver and passengers (automotive)◮ Using active flow control for reducing drag on vehicles◮ Heat transfer in engines: development of simulation method

L. Davidson, FFI, April 2019 Applied and Fundamental 2 / 25

WATER: VOLVO CARS, FFI PROJECT, 2006-2011

Water inlet

U∞


WATER: EXPERIMENT

(A) Scatter plot. Air velocity Vair = 13 (B) Different air velocities.

FIGURE: Velocity of waterdrops that left the table.

ρℓhcVair

σ= −155 + 280Vair

T. Tivert and L. Davidson Experimental study of water transport on a generic mirror, InternationalConference on Multiphase Flow,ICMF, Tampa, FL, US, 2010.


ENGINES: VOLVO CARS, FFI PROJECT, 2009-2014

Real engine

Simplified case

Piston top simplified as a

series of horizontal and

inclined plans

Impinging jet flow and heat

transfer


ENGINES: EXP & SIMULATIONS

(A) Setup (B) Computational domain

FIGURE: Simplified setup

M. Bovo and L. Davidson “Direct comparison of LES and experiment of a single-pulse impingingjet”, International Journal of Heat and Mass Transfer, Vol. 88, pp. 102-110, 2015.


ENGINES: RESULTS

(A) Velocities at three instants.

Ve

locitie

sa

tth

ree

insta

nts

Surface temperature

wall normal velocity, 0.6ms


ACOUSTICS, VOLVO & VCC, FFI PROJECT 2014-2018

Winds reen

A-pillar

Plenum

Du k tail

Hood

Side mirror

Side window

Beltline

x

y

z

side mirrorCavity


AERO-VIBRO ACOUSTICS: FFI PROJECT 2014-2018

An important source of the interior noise in vehicles is the window vibration that

is excited by

◮ the exterior flow (indirect noise generation).◮ the exterior flow-induced noise (direct noise transfer).

Boundary layer

Noise from

Vortices

Structure

Noise due to Noise due tohydrodynamicacoustic

Exterior side

Interior side

vortices

pressure pressure

Vibration

Noise fromboundary layer


APPLICATION 1 – GENERIC SIDE-VIEW MIRROR (1)

The exterior turbulence creates interior noise by making the window glass vibrate

1.4

0.8

0.2

0.2

1.61.4

1.2

0.1

1.2

0.1

0.1 0.1

X

Y

Z

Glass window

GSV Mirror

Rigid plate

Cavity

(A) Domain with mirror, glass window

and cavity.

Pressure of interior noise

Generic side view mirror

Glass window

Cavity

Vortices

Pressure on window

(B) CFD, vibrating window, noise

propagation in cavity.

H.-D. Yao & L. Davidson, “Generation of interior cavity noise due to window vibration excited byturbulent flows past a generic side-view mirror”, Phys. Fluids, Vol. 30, 036104, 2018



Compressibility: compressible vs. incompressible.

Turbulence modeling: detached eddy simulation vs. large eddy simulation.

Acoustics: direct vs. indirect simulation using acoustic perturbation equations.

Grid topologies: trimmed vs. polyhedral cells.

X

Z

(a)

(b)

7

6

5

4 3 2 1

Trimmed mesh

X

Z

(a)

(b)

X

Y

Polyhedral mesh



The contributions of the exterior hydrodynamic and acoustic pressure

fluctuations to the interior noise generation are addressed.

0.05 0.12 0.19 0.26 0.33 0.4

C-LES

I-DES with polyhedral meshI-DES with trimmed mesh

C-DES

0.3 0.6 0.9 1.2 0.3 0.6 0.9 1.2

x x

0.6

0.3

0

-0.3

-0.6

0.6

0.3

0

-0.3

-0.6

z

z

(A) RMS values of surface pressure

fluctuations

(a)

(b)

(B) SPLs of interior noise at Mic. 4

(bottom corner)


APPLICATION 2 – FULL-SCALE TRUCK (1)

The installation effect of a side-view mirror is studied.

The simplification strategy for a full-scale production truck is validated.

(a)

(b)

Original and simplified trucks

X

Z

YX

Y

Z

Window

Upper mirror head

Bottom mirror head

Mirror bracket

Window

Upper mirror head

Bottom mirror headMirror bracket

A-pillar

Side-view mirror components, the A-pillar and the window

H.-D. Yao & L. Davidson, “Simplifications Applied for Simulation of Turbulence Induced by a SideView Mirror of a Full-Scale Truck Using DES”, SAE 2018-01-0708, 2018.H.-D. Yao, L. Davidson, Z. Chroneer, “Investigation of interior noise from generic side-view mirrorusing incompressible and compressible solvers of DES and LES”, SAE 2018-01-0735, 2018.


APPLICATION 2 – FULL-SCALE TRUCK (2)

A hybrid mesh of trimmed and polyhedral cells is employed.

The mesh is sufficiently refined near the mirror and A-pillar to resolve turbulent

flow structures.

X

Y

Z

(a)

(b)

X

Y

Z

A hybrid mesh of trimmed & polyhedral cells

X

Z100

-120

-340

-560

-��

-��

(Pa)

X

Y

Snapshots of Q-criterion


AERODYNAMICS: AB VOLVO, FFI PROJECT 2013-2018

A−pillar


Uinf


Uinf


Uinf Jet

Uinf

Membrane

Time

Jet

0


Jet

Uinf

Membrane

Time

Jet

0

D

LW

S

W

K

A

z

y


Uinf

Uinf

D

AC

y/W

x/W

x

BA

BR

L

0.5

1

1 1.6

domain

y

z

domain

Laser

Camera

Side

Rear

AFC


G. Minelli, E. Adi Hartono, V. Chernoray, L. Hjelm and S. Krajnovic “Aerodynamic flow control fora generic truck cabin using synthetic jets”, Journal of Wind Engineering and IndustrialAerodynamics, Vol. 168, pp. 81-90, 2017.


AFC OFF AFC ON

G. Minelli, S. Krajnovic, B. Basara and B. Noack, “Numerical Investigation of Active Flow ControlAround a Generic Truck A-Pillar”, Flow, Turbulence and Combustion, Vol. 97, pp. 1-20, 2016.


ENGINES: AB VOLVO, FFI PROJECT ON-GOING

FIGURE: Internal engine combustion of mixture of air and direct injecteddiesel.

piston

valves

spray


IMPINGING JET

FIGURE: Turbulent axisymmetric impinging jet.


TEST CASE

USED MESH TYPES

Mesh for low-Reynolds-

number, LRN, modelingMesh for Numeric

Wall Function, NWF

Mesh for high-Reynolds-

number, HRN, modeling


WALL FRICTION

FIGURE: Impinging jet at ReD = 220000, comparing; : default LRN,

: LRN with NWF mesh, face flux, : wall flux.


SPEED-UP

0 1,000 2,000 3,000

Wall flux

Face flux

LRN w NWF mesh

HRN

LRN

313

3,470

493

652

624

Steady-state solver time [s]

J.-A. Backar, L. Davidson, “Evaluation of numerical wall functions on

the axisymmetric impinging jet using OpenFOAM”, International

Journal of Heat and Fluid Flow, Volume 67, pp. 27-42, Part A, 2017.L. Davidson, FFI, April 2019 Applied and Fundamental 23 / 25

AFC AND MACHINE LEARNING

Project leaders: S. Krajnovic and V. Chernoray

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Left: A sketch of the flow separation

Right: The model placed in the wind tunnel

Object: teach the controller to miminize drag by finding optimal

A1,A2, f1, f2 in S = A1 sin(2πf1t) + A2 sin(2πf2t)

Learning procedure is based on a genetic algorithm (GA)

optimization script


APPLIED AND FUNDAMENTAL RESEARCH: HOW TO

There is a danger that very applied FFI projects get higher priority

than fundamental research





How to combine applied & fundamental research?





How to combine applied & fundamental research?◮ Choose the right partner (persons) in industry





How to combine applied & fundamental research?◮ Choose the right partner (persons) in industry◮ In a project: do both fundamental research (first) and then apply it

(maybe by your industrial partner)





How to combine applied & fundamental research?◮ Choose the right partner (persons) in industry◮ In a project: do both fundamental research (first) and then apply it

(maybe by your industrial partner)◮ Go out and visit the industry; make presentations.


Documents

How to carry out fundamental research together with industrylada/slides/slides_ffi_april_2019.pdf · 2019-04-04 · APPLIED AND FUNDAMENTAL RESEARCH I will show ﬁve nice examples