File_1_12_Numerical Modelling of River Dynamics Wi

7/28/2019 File_1_12_Numerical Modelling of River Dynamics Wi

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withwith IberIber

GiD based tool for the anal sis of water and sediment

flows in river and estuaries

Ernest Blad, Luis Cea, Georgina Corestein, Enrique Escolano


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THE MODEL

apa es

Simulation of free surface flow in rivers and estuaries Assessment of flood areas. Calculation of main flow zones.

Hydraulic calculation of open channel networks.

Sediment transport: erosion and sedimentation


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ANTECEDENTS

T r i l l n CARPA

GiD


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STRUCTURE

HYDRODYNAMICS

Velocity

Depth

SEDIMENT TRANSPORT

Suspended Load

TURBULENCE

Turbulent viscosity

Bed Load Turbulent Energy and disipation


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HYDRODYNAMICS

2D Shallow water equations

yxqqh

0t x

2 2

x y b,xbx x x xt t

q q zq q U Uhg gh h h

t x h 2 y h x x x y y

2 2

y x y y b,y y ybt t

q q q q U Uzhg gh h h

t x h y h 2 y x x y y

Solution: FINITE VOLUME METHOD

Numerical scheme: High resolution Godunov Method based on Roe

Mesh: non-structured triangles and quadrilaterals


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THE INTERFACE

Fully integrated in GiD and customized toobtain a unified environment.

Uses GiD standards.

Include general data, boundary conditionsand materials.

pec c oo s


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SEDIMENT TRANSPORT

Exner equation of sediment conservation

sb,ysb,xbqqZ

1 p D - E

t x y

E D

transport

bZ

V1.7: uniform sediment


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BEDLOAD:

Formulae

Van Rijn

Meyer-Peter & Mller

(Wong & Parker

version)

APPLICABILITYSand and gravels

APPLICABILITY

Gravels until 30 mm

Equation:Equation:

.*

sb 0.3*

1.5*

T 0.3 q 0.053 D

T

3/2

* * *sb bs cq = 3.97 -

bs c

*

c

-

T

sb 0.3

*

. .D


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BEDLOAD: slo e correction

Bottom effective tension = Tension due to flow + weight component

flow

weighteffective tension


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BEDLOAD: Interface

Inlet:

ear capac ty according to formulation

by mean a table

Clear water

none solid discharge

u e :

sediment continuity


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BEDLOAD: Validation

Test case with exact solution proposed by De Vriend (1987)

Conical Sand dune


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BEDLOAD: Validation

Grass formula An le of s read

Using mg= 3, results =21.7867893

25 38


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Embankment failure b Overto in

Experimental model: dam built withwell graduated sand and volcanic

ashes


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Numerical Model: geometry and meshcreated with Iber.


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Comparison with a real event


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SUSPENDED SEDIMENT: E uations

Turbulent transport of suspended sediment

y txhU C hU ChC C

h E D

c,t

deposition

Granular material: *

s a aE D W c c

Cohesive soil :b

ce

E = M 1

bs a

cd

D W c 1


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SUSPENDED SEDIMENT: Interface

Inlet:

Open boundary

concentration

Source Discharge and concentration

No solid discharge

Outlet:

Sediment continuty


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REVERSIBLE HYDROPOWER

PLANT OF MONTNEGRE

Lower reservoir: 160Hm3

Ribarroja reservoir

pper reservo r: m

Pumping discharge:380m3/sTurbine discharge: 400m3/s

Objective: Effect of new powerplant on river-reservoir morphodynamics


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STUDY AREA


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SIMULATIONS

1 164 m/s Pumping (no inlets or out lets, ini tial elevat ion 69,5)

2 328 m/s Pumping (no inlets or out lets, ini tial elevat ion 69,5)

3 328 m/s Pumping, then 400 m/s turbinate (no inlets or outlets, initial elevation 69,5)

4 400 m/s Turbinate (no inlets or out lets, ini tial elevat ion 68.4)

5 328 m/s Pumping and simulataneous inlet of 328 m/s in Mequinenza (init ial elevation 69,5)

7 164 m/s Pumping, then 200 m/s turbinate (no inlets or outlets, ini tial elevation 69,5)

8 200 m/s Turbinate (no inlets or out lets, ini tial elevat ion 68.4)

10 400 m/s turbinate, and simulatneaus outlet of 400 m/s in Ribaroja (no inlets or outlets, init ial elevation 69,5)

11 328 m/s Pumping, then 400 m/s turbinate , 7 cycles (no inlets or outlets, init ial elevation 69,5)

12 164 m/s Pumping, then 200 m/s turbinate , 7 cycles (no inlets or outlets, init ial elevation 69,5)


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328 m/s Pumping, then 400 m/s turbinate (no inlets or outlets, initial elevation 69,5)

Depth Elevation Erosion - deposition


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328 m/s Pumping, then 400 m/s turbinate (no inlets or outlets, initial elevation 69.5)

Depth Elevation Erosion Deposition


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Depth Elevation Erosion Deposition


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Elevation Erosion Deposition


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7 cycles - Erosion

7 cycles - Sedimentation


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7 cycles

7 cycles Volume of sediment into the upper reservoir


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7 cycles Volume of sediment into the upper reservoir

CONCLUSIONS


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CONCLUSIONS

The interface of Iber, based on GiD, is user friendly, flexible

Iber s morphodynamic module has been enhanced and

ver e or e oa an suspen e ranspor

engineering problems

e n er ace s user r en y an s o s ex y an

capabilities.


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Contact us in www.iberaula.es

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