Trondhei Trondheim (NO), 8th of m (NO), 8th of July 2004, 5.17a.m. - - PowerPoint PPT Presentation

Trondhei Trondheim (NO), 8th of m (NO), 8th of July 2004, 5.17a.m. July 2004, 5.17a.m.

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Outline Outline

• 1. Introduction
• 2. CFD code SSIIM
• 3. Application and Results
• 4. Conclusion and Outlook

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Introduction Introduction

• 1. Introduction
• river management
• management of water quality
• ....many more topics

Why estimate sediment transport?

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Introduction Introduction

Patt (1998)

river management

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Introduction Introduction

water quality management

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Outline Outline

1.Introduction

• 2. CFD code SSIIM
• 3. Application and Results
• 4. Conclusions and Outlook

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CFD code SSIIM - CFD code SSIIM - Basics asics

SSIIM acronym for runs on standard PC and is freeware Sediment Simulation In Intakes Sediment Simulation In Intakes with Multiblock option with Multiblock option developed by Nils developed by Nils R. B. Olsen at NTNU

• R. B. Olsen at NTNU

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CFD code SSIIM - CFD code SSIIM - Basics asics

structured, non-orthogonal grid finite volume approach fully 3D

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CFD code SSIIM - CFD code SSIIM - Hydraulics ydraulics

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III Pressure term SIMPL SIMPLE Method (Patankar 1980) Method (Patankar 1980)

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I Transient term Implicit Method Implicit Method

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II Convective term First First/Second Orde cond Order Scheme r Scheme

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IV Stress term Boussinesq Approx ussinesq Approx. & k- . & k-ε turb. closure

• turb. closure

(Rodi 1993) (Rodi 1993)

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CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism

Shields‘ approach (1936)

θ

z

u(z)

x

τ < { τ

c

θ

z

u(z)

x

τ >τc{

no partic particle le motion motion pa particle rticle motion motion

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CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism

θ z x

y

Q α>0° and and θ>>0° ? 0° ?

α=0°

α x

y

z

Shi Shields lds

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CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism

(Dey, 2001) (Dey, 2001)

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CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism

Dey Deys e empirica pirical equa quation ion

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CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism x z u(z)

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CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism

x z u(z)

suspension load bed load bed material

δb

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CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism

x z u(z)

suspension load bed load bed material rolling

δb

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CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism

x z u(z)

suspension load bed load bed material saltation

δb

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CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism

x z u(z)

suspension load bed load bed material rolling saltation Suspension

δb

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CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism

x z u(z) δb

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CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism

x z u(z) C(z)

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CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism

x z u(z) C(z)

conv convection-diffusion ection-diffusion eqn. eqn.

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Outline Outline

1.Introduction

• 2. CFD code SSIIM
• 3. Application and Results
• 4. Conclusions and Outlook

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Application and Results

Capabilities and limitations of SSIIM with regard to sediment transport Aim: Verification: physical experimental run

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Application and Results–physical model

125 mm 125 mm 350 mm 425 mm 200 mm 117° 490mm C L

• uter bank

inclined area inner bank

plan view:

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side view:

100 mm 300 mm 150 mm 50 mm sand α =30°

Application and Results–physical model

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Application and Results–numerical model

side view:

∆y ∆z

1 2 3 4

Qin Qout

plan view:

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Application and Results–numerical model

Q=1.0 l/s discharge h=50 mm mean flow depth I0=0.005 mean bed slope D50=0.7 mm mean particle diameter Flow condition Flow condition ∆t=4h simulation time

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Application and Results – Exp. vs. SSIIM

Experiment/measurements Computed by SSIIM without Dey algorithm Q Q

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Application and Results – Exp. vs. SSIIM

Computed by SSIIM with Dey algorithm Q Experiment/measurements Q

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Application and Results – Exp. vs. SSIIM

Computed by SSIIM with Dey algorithm Photo by Guymer and Dutton, Sheffield Q

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Conclusions and Outlook Conclusions and Outlook

• …improved results if using ‘sloping bed

algorithm’.

SSIIM shows…

• …a quantitative overprediction in erosion.

an interesting topic for further research!

• …that overall trends in deposition and erosion

agree on the main points.

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Conclusions and Outlook Conclusions and Outlook

…to conclude:

• Hydraulic calculation 3D
• Sediment transport model 1D – empirical input

Applying these models give fairly good agreement with measurements

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Conclusions and Outlook Conclusions and Outlook

…to conclude:

• SSIIM is a reliable instrument in river,

environmental and sedimentation engineering.

• SSIIM’s ability to run on standard PCs will

promote its distribution among practical working hydraulic engineers,

• and will cause it to be accepted as a design tool

for water and environmental related engineering.

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Conclusions and Outlook Conclusions and Outlook

Last but not least:

eye candy: time-dependent development of bed topography

.....Thank you for your attention. Diploma Thesis available @:

http://www.stud.uni-karlsruhe.de/~uj8a/thesis/da.pdf

.....Thank you for your attention.