Modelling tyre water splash with Openfoamhani/OFGBG15/OF2015_VCC_NaiXianLU... · 2015. 11. 12. · Modelling tyre water splash with Openfoam 1 Alper Cesur, Dragos Moroianu, NaiXian

Modelling tyre water splash

with Openfoam

1

Alper Cesur, Dragos Moroianu, NaiXian Leslie LUContamination & Core CFD, Volvo Car Corporation

2015-11-11 MODELLING TYRE WATER SPLASH WITH OPENFOAM - GOTHENBURG REGION OPENFOAM USER GROUP MEETING

What is splash?

2015-11-11 2MODELLING TYRE WATER SPLASH WITH OPENFOAM - GOTHENBURG REGION OPENFOAM USER GROUP MEETING

Why is splash a problem?

2015-11-11 3MODELLING TYRE WATER SPLASH WITH OPENFOAM - GOTHENBURG REGION OPENFOAM USER GROUP MEETING

• Soaking-wet pedestrians

• Engine belt water contamination

• Air ventilation pipe on gearbox

• Failure of electrical component

• High water loads on critical components

Source: http://www.metro.co.uk/news/208309-car-puddle-soakings-new-youth-craze

2015-11-11 4MODELLING TYRE WATER SPLASH WITH OPENFOAM - GOTHENBURG REGION OPENFOAM USER GROUP MEETING

𝜔𝑊𝐻𝐸𝐸𝐿 = 25 𝑟𝑎𝑑 𝑠

Model description

Force comparison on a metalic plate around a splashing tyre

• Qualitative (previous studies)

• Quantitative

Pressure plate

Governing equations

2015-11-11 5MODELLING TYRE WATER SPLASH WITH OPENFOAM - GOTHENBURG REGION OPENFOAM USER GROUP MEETING

• Incompressible flow – Large Eddy Simulation

𝜕𝑡𝛼 + 𝛻 ∙ 𝛼 𝐯 = 0

• A single fluid mixture assumption (VOF)

𝜕𝑡 𝐯 + 𝛻 ∙ 𝐯⨂ 𝐯 = −1

𝜌𝛻 𝑝 + 𝛻 ∙ ( 𝐒 − 𝐁)

𝛻 ∙ 𝐯 = 0

𝐁 =1

𝜌𝐯⨂𝐯 − 𝐯⨂ 𝐯 Smagorinsky Subgrid-scale model

2015-11-11 6MODELLING TYRE WATER SPLASH WITH OPENFOAM - GOTHENBURG REGION OPENFOAM USER GROUP MEETING

Current cfd approach

snappyHexMesh

• 25 M cells

• 1.25mm tyre surface

• 1.25mm cylindrical refinement box around the pressure plate

Mesh Resolution Study

2015-11-11 7MODELLING TYRE WATER SPLASH WITH OPENFOAM - GOTHENBURG REGION OPENFOAM USER GROUP MEETING

Current cfd approach

𝑽 𝑦 =𝐶𝑦

𝑦𝑚𝑎𝑥 − 𝑦𝑚𝑒𝑑𝑦 − 𝑦𝑚𝑒𝑑 𝑽 𝑦 =

𝐶𝑦

𝑦𝑚𝑎𝑥2 − 𝑦𝑚𝑒𝑑

2 𝑦2 − 𝑦𝑚𝑒𝑑2

Linear Profile: Parabolic Profile:

𝑦𝑚𝑎𝑥𝑦𝑚𝑒𝑑

Application of two different velocity profiles at the first layer of tyre tread patch

Method 𝑭𝑵@ 0.8 sec. [1] 𝑭𝑵@ 1.8 sec. [1]

Default LES 0.735 -

Linear Profile 0.948 0.889

Parabolic Profile 0.952 0.911

2015-11-11 8MODELLING TYRE WATER SPLASH WITH OPENFOAM - GOTHENBURG REGION OPENFOAM USER GROUP MEETING

Current cfd approach

2015-11-11 9MODELLING TYRE WATER SPLASH WITH OPENFOAM - GOTHENBURG REGION OPENFOAM USER GROUP MEETING

Otherwise...

compressibleInterPhaseChangeFoaminterPhaseChangeFoam

10

NaiXian Leslie

LU

Ph.D, First CFD Engineer

T +46-31-3257188

[email protected]

Contamination & Core CFD

VOLVO CAR CORPORATION

Questions?

2015-11-11 MODELLING TYRE WATER SPLASH WITH OPENFOAM - GOTHENBURG REGION OPENFOAM USER GROUP MEETING