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 3

Introduction Introduction 1. Introduction Why estimate sediment transport? • river management • management of water quality •....many more topics 4

Introduction Introduction river management Patt (1998) 5

Introduction Introduction water quality management 6

Outline Outline 1.Introduction 2. CFD code SSIIM 3. Application and Results 4. Conclusions and Outlook 7

CFD code SSIIM - CFD code SSIIM - Basics asics SSIIM acronym for 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 runs on standard PC and is freeware 8

CFD code SSIIM - CFD code SSIIM - Basics asics fully 3D finite volume approach structured, non-orthogonal grid 9

CFD code SSIIM - CFD code SSIIM - Hydraulics ydraulics I II III IV I Transient term Implicit Method Implicit Method First/Second Orde First cond Order Scheme r Scheme Convective term II Pressure term SIMPL SIMPLE Method (Patankar 1980) Method (Patankar 1980) III IV Stress term Boussinesq Approx ussinesq Approx. & k- . & k- ε turb. closure turb. closure 10 (Rodi 1993) (Rodi 1993)

CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism Shields‘ approach (1936) z u(z) τ < τ { no partic particle le motion motion c θ x z u(z) τ >τ c { particle pa rticle motion motion θ x 11

CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism z Shi Shields lds α=0° y Q θ x α>0° and and θ>> 0° ? 0° ? z α x y 12

CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism (Dey, 2001) (Dey, 2001) 13

CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism Dey Deys e empirica pirical equa quation ion 14

CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism u(z) z x 15

CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism u(z) suspension load z δ b bed load bed material x 16

CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism u(z) suspension load z δ b bed load bed material x rolling 17

CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism u(z) suspension load z δ b bed load bed material x saltation 18

CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism u(z) suspension load Suspension z δ b bed load bed material x rolling saltation 19

CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism u(z) z δ b x 20

CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism u(z) z x C(z) 21

CFD code SSIIM – CFD code SSIIM – sediment transport mechanism ediment transport mechanism conv convection-diffusion ection-diffusion eqn. eqn. u(z) z x C(z) 22

Outline Outline 1.Introduction 2. CFD code SSIIM 3. Application and Results 4. Conclusions and Outlook 23

Application and Results Aim: Capabilities and limitations of SSIIM with regard to sediment transport Verification: physical experimental run 24

Application and Results–physical model plan view: 350 mm 425 mm inclined outer bank area C L inner bank 125 mm 125 mm 200 mm 117° 490mm 25

Application and Results–physical model side view: 300 mm α =30° 50 mm 100 mm 150 mm sand 26

Application and Results–numerical model side view: ∆ z ∆ y plan view: Q out Q in 1 2 3 4 27

Application and Results–numerical model Flow condition Flow condition discharge Q=1.0 l/s mean flow depth h=50 mm mean bed slope I 0 =0.005 mean particle diameter D 50 =0.7 mm simulation time ∆ t=4h 28

Application and Results – Exp. vs. SSIIM Q Q Experiment/measurements Computed by SSIIM without Dey algorithm 29

Application and Results – Exp. vs. SSIIM Q Q Experiment/measurements Computed by SSIIM with Dey algorithm 30

Application and Results – Exp. vs. SSIIM Q Photo by Guymer and Computed by SSIIM Dutton, Sheffield with Dey algorithm 31

Conclusions and Outlook Conclusions and Outlook SSIIM shows… • …improved results if using ‘sloping bed algorithm’. • …that overall trends in deposition and erosion agree on the main points. • …a quantitative overprediction in erosion. an interesting topic for further research! 32

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 33

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. 34

Conclusions and Outlook Conclusions and Outlook Last but not least: eye candy: time-dependent development of bed topography 35

Diploma Thesis available @: http://www.stud.uni-karlsruhe.de/~uj8a/thesis/da.pdf .....Thank you for your attention.

.....Thank you for your attention.