physical and numerical modeling of porous bonded revetments · pdf filedevelop generic and...

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Leichtweiß-Institute for Hydraulic Engineering and Water Resources

Department of Hydromechanics and Coastal Engineering

Physical and numerical modeling of porous bonded revetments

Juan C. Alcérreca Huerta, Gisa Foyer, Sven Liebisch & Hocine Oumeraci | 26th February 2013 | FZK-Kolloquium 2013

Photo: ©BASF

Contents

� Motivation & Objectives

� Large-scale tests: GWK tests overview

� Numerical simulations with COBRAS-UC

� Small-scale tests: BoPoRe project

� Numerical simulations within OpenFOAM®

� Summary and Remarks

26th February 2013 | Alcérreca Huerta et al. | FZK-Kolloquium 2013| Slide 2

� Summary and Remarks

Contents






� Summary and concluding remarks



0

0

Motivation & Objectives

Rising sea water levels make the development of new coastal protection systems

necessary. An innovative approach to these new requirements is the use of

porous bonded revetments.

Improve understanding of the processes and variables involved in the interaction

between waves and porous revetments and how to model it for the analysis of its

hydraulic performance


hydraulic performance

Small-scale Tests(LWI)

Numerical modeling(COBRAS-UC)

(OpenFOAM® model framework)

Large-scale Tests(GWK)

Contents









� Objective

� Improve understanding of wave-structure

interaction & PBA hydraulic performance.

� Test program

� Surf similarity parameter : ξm = 1.3 - 8.1

� Deep water wave height: Hm = 0.17 – 1.4 m

� Wave period: Tm = 3.0 – 8.1 s

Large-scale tests: GWK-tests overview


m

� Initial water depth: h0 = 3.4 - 4.2 m

� Revetment thickness: drev = 0.15; 0.25 & 0.35 m

� Slope steepness: cot α = 3

� Analysis in Oumeraci et al. (2010)

� Reflection analysis

� Wave run-up and run-down

� Pressures on and just beneath the revetment

� Pore pressures in sand foundation

Large-scale model tests in the Grosser Wellenkanal

(GWK)

Large-scale tests: GWK-tests overview

Polyurethane Bonded Aggregate (PBA) revetment in GWK and location of wave gauges

PBA revetmentPBA revetment

Existing asphalt dike with 1:6 slope


SandcoreSandcore

5 - 85 - 8

0 Y

po

sit

ion

0 Y

po

sit

ion

Wave gauges 1 – 13Wave gauges 1 – 131 - 41 - 4 99 1010 11-1311-13

0 X position0 X position

+11°

7,0

0

2,5

04,2

0

0,00m

7,00

4,00

Dipl.-Ing.G.BERGMANN

-

Container I Container IVContainer V

1 : 6

5,00m

Wavegauge

3,0

0

1 :

3

Sandkern

vorhandener Asphaltdeich

1 : 6

Deckwerk ELASTOCOASTPBA revetment


Sandcore

5 - 8

0 Y

po

sit

ion

Wave gauges 1 – 131 - 4 9 10 11-13

0 X position

Tested PBA revetment models in GWK

Experim

enta

l set-

up


PBA: crushedlimestone (20/40 mm)

Filter layer: crushedlimestone (20/40 mm)

Sand foundation(D50 = 0.34 mm, U = 2.11)

Geotextile (Terrafix 609)

Model A Model B Model C

Tested PBA revetment models in GWK

PB

A r

evetm

entm

odels PBA: crushed

granite (16/36 mm)

Filter layer: crushedgranite (16/36 mm)

Sand foundation(D50 = 0.34 mm, U = 2.11)

Geotextile (Terrafix 609)

Contents









WG

01

WG

02

WG

03

WG

04

WG

05

WG

06

WG

07

WG

08

WG

09 drev

Impermeablefoundation

7m

40m

Numerical simulations with COBRAS-UC

� Test conditions

Test set-

up

� Objective

� Extend the range of the tested conditions in the GWK


� Test conditions

� Deep water mean wave height Hm = 0.15 – 1.03 m

� Mean wave period Tm = 2.99 – 9.00 s

� Surf similarity parameter ξm = = 0.62 – 19.40

� Initial water depth h0 = 4.0 m

� Revetment thickness drev = 0.00; 0.25 & 0.50 m

� Slope steepness cotα = 1.5; 2; 3; 4 & 6

� Cell sizes ∆x = 2 – 4 cm; ∆y = 2 – 7 cm

� Porosity of revetment & Forchheimer coefficients: n= 0.4; αf = 200; βf = 0.8, Cm = 0.34


0.6

0.8

1.0R

eflection c

oeff

iecie

nt

Cr

�� = tan ��

Comparison between GWK Results and COBRAS-UC Simulations


0 2 4 6 8 10 12 14 16 18 20

0.0

0.2

0.4

Numerical results

Exp. results - Mod. A/B

Exp. results - Mod. B/C

Reflection c

oeff

iecie

nt

C

Surf similarity parameter ξm

�� = tan ��0

0.6

0.8

1.0R

eflection c

oeff

iecie

nt

Cr

� = 0.87 ⋅ ��211.53 + ��2

� = 0.79 ⋅ ��212.13 + ��2


Effect of revetment thickness on reflection (COBRAS-UC)


0 2 4 6 8 10 12 14 16 18 20

0.0

0.2

0.4

drev

=0 m

drev

=0.25 m

drev

=0.5 m

Reflection c

oeff

iecie

nt

C

Surf similarity parameter ξm

�� = tan ��0

drev=0m

� = 1.02 ⋅ ��28.16 + ��2

� = 0.87 ⋅ ��11.53 + ��2 � = 0.79 ⋅ ��2

12.13 + ��2

drev=0.5m

drev=0.25m

Contents









Small-scale tests: BoPoRe project

� Objective

� Describe the effect of the porosity androughness of revetments on wave run-up

and run-down, wave-induced loads and

wave-induced pore-pressure.

� Develop generic and process-based

formulae for the design of PBA revetments

with an explicit consideration of porosity


� BoPoRe Project description

� BoPoRe = Bonded Porous Revetments.

� Facilities of the Leichtweiß-Institute (LWI) in

Braunschweig.

� Funded by the German Research Council

(DFG).


Set-up



Reflection behavior for different roughnesses of impermeable revetments


Reflection behavior for different porosities of smooth revetments




Reflection behavior for highly porous revetments with different roughnesses


Both porosity and roughness have a decreasing effect on the reflection coefficient, but the effect of roughness is more significant

Contents





� Numerical simulations within OpenFOAM ®




Numerical simulations within OpenFOAM ®

� Objective

� Extend GWK tests conditions with…

� Improve shortcomings observed in other

models.

� Reproduce hydrodynamic processeson/beneath the revetment.

� Develop generic and process-based

formulae for the design of PBA

revetments.


revetments.

� Numerical model features

� OpenFOAM® : Open source CFD toolbox

� Volume-Averaged RANS-VOF model

� New solver developed within the

OpenFOAM framework:

wavePorousFoamwaveFoam (Jacobsen et al., 2012)

porousInterFoam

Numerical simulations within OpenFOAM ®

Comparison between GWK Results and wavePorousFoam simulations


Numerical simulations within OpenFOAM

Simulations performed with wavePorousFoam


Contents









Summary and concluding remarks

� The large scale tests in the GWK mostly serve as a kind of bench mark tests for all

following investigations.

� Using different modelling approaches, (large scale tests, small scale tests and numerical

simulations) it is possible to improve the knowledge on the interaction between waves

and porous revetments of different roughnesses and porosities on sand foundations.

� The effects of roughness and porosity were analyzed using the reflection coefficient as a

comparative parameter between the test series. It was found that the surface roughness


comparative parameter between the test series. It was found that the surface roughness

affects the reflection more than the porosity.

� Some shortcomings of the numerical model COBRAS-UC were identified. Therefore, a

new solver was developed in the OpenFOAM® framework and validated by experimental

data.

� The new model, although still under development, show a better performance than

COBRAS-UC in terms of the prediction of the porous flow in the revetment

Thank you for your attention!

Juan Juan C. C. AlcérrecaAlcérreca Huerta, Huerta, GisaGisa Foyer, Sven Foyer, Sven LiebischLiebisch


Juan Juan C. C. AlcérrecaAlcérreca Huerta, Huerta, GisaGisa Foyer, Sven Foyer, Sven LiebischLiebisch& & HocineHocine OumeraciOumeraci

Leichtweiß-Institute forHydraulic Engineering and Water ResourcesTechnischeTechnische UniversitätUniversität BraunschweigBraunschweig, Germany, Germany

Tel.: +49 531 Tel.: +49 531 391 391 -- 3932, 3932, -- 79167916

www.tuwww.tu--braunschweig.de/lwi/hyku/braunschweig.de/lwi/hyku/

j.alcerrecaj.alcerreca--huerta@[email protected]

[email protected]@tu--bs.debs.de

[email protected]@tu--bs.debs.de

BASF Polyurethanes GmbHBASF Polyurethanes GmbH

DBU DBU (Deutsche (Deutsche BundesstiftungBundesstiftung UmweltUmwelt))

DFG DFG (Deutsche (Deutsche ForschungsgesellschaftForschungsgesellschaft))

CONACyTCONACyT--DAADDAAD

AcknowledgementsAcknowledgements

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