27-6-2016

Challenge the future

Delft University of Technology

Zoetwaterpluim in de Rijn-Maasmond

(3D hydrodynamica)

Pilot applicatie

Arjen Luijendijk

Niek Waagmeester

Freek Scheel

Saulo Meirelles

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Sand Motor (ZM) at the Dutch coast

Area of interest: Sand Motor Mega-nourishment of 21 mln m3

Scale of intervention:

• 2 km alongshore • 1 km cross-shore

Large signal-to-noise ratio

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Aerial photograph 3D view of measured bed levels

Sand Motor – Morphological evolution

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Motivation – Field campaign MegaPEX Multi-disciplinary field measurements for 6 weeks – Sept14

Goal: Operational hydrodynamic predictions for field measurements

Dye experiment

Drifters

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Coastal processes around the ZM

Hydrodynamics

• Tidal currents

• Wind- and wave driven

• Fresh river outflow

Waves

• From SW and NW

Sediments

• Sandy shores

• Cohesive sediments from river

Rotterdam

Delft

World Forum

Curvilinear - Zeedelta model

No 3D operational model available covering both river mouth and ZM

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Boundary conditions • Tidal conditions • Fresh river discharges • Wind Resolution • Deeper water: ~300 m • Sand engine: ~17 m

Numerics • ~110,000 nodes • 20 layers • Requires 4hrs to run 1day on 8 processors 2.6GHz

Computational

mesh

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Overlaying various data sources

• AHN

• Aerial images

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Overlaying various data sources

• AHN

• Aerial images

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Overlaying various data sources

• Lidar (kusthoogte)

• AHN

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D-HYDRO Suite

Benefits using Flexible Mesh compared to Curvilinear

• Optimal resolution where needed

• Optimisation of #grid cells (~50% of curvi grid)

• Variable time step

• Parallelization (8 is semi-optimal for this simulation)

• BMI compliant – communication with other software

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Model results – Surface salinities

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Validation

• Quantitatively temporal

• In-situ at Hoek van Holland

• Fixed, continuous measurements

• In—situ: 13-hr measurements at the Zandmotor

• Profiles from a ship

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Validation – currents and salinities

Figure 1: Measured and modelled salinity at observation station Hoek van Holland. Coloured dots indicate measurements every 10 minutes at 2.5, 4.5 and 9 m depth. Coloured lines indicate model results of the 5 sigma layers. Measurements have the same colour as the closest model layer.

Velocities at Zandmotor

Salinities at 3 locations in water column (HvH)

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But how do you validate spatial

behaviour?

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Validation

• Quantitatively temporal

• In-situ at Hoek van Holland

• Fixed, continuous measurements

• In—situ: 13-hr measurements at the Zandmotor

• Profiles from a ship

• Spatial behaviour? Qualitatively by Remote Sensing:

• X-Band radar (24/7)

• Sentinel 2 images (optical; every 10 days)

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Remote Sensing X-Band radar images every 5 min

• Model validation - fronts

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Remote Sensing Satellite image of 25 Jan 2016 11:03

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Observed at 25 Jan 2016 11:03

Computed at 25 Jan 2016 12:00

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In-situ measurements

17 Oct 2014 7:50

17 Oct 2014 13:50

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Alongshore Cross-shore

Obs

Comp

Velocities

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Findings

• Flexible Mesh opens new possibilities

• Tendency to include larger scale domains

• Need for qualitative comparisons with RS

• Future outlook:

• FM can be relatively easy coupled to other programs.

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Work in progress

• Spatial coupling of FM Morphology with aeolian transport model

• Temporal de- / activation of processes

Long waves

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Vragen?