DSD-NL 2014 - NGHS Flexible Mesh - Tetratech pilot oil spill modeling, Freek Scheel, Deltares

www.tetratech.com

Baía de Guanabara

RJ – BRASIL

Delft3D FM

TETRA TECH Team:

Maria Fernanda Fiedler

Eduardo Yassuda

DELTARES:

Freek Scheel

Deltares Software Center

Baía de Guanabara (Guanabara Bay)

Guanabara Bay is located in the Southeastern Coast of Brazil, in the state of Rio de Janeiro

Rio de

Janeiro

Niterói

30 km

Baía de Guanabara (Guanabara Bay)

• Besides touristic relevance also economic activity: harbors, docks, shipyards, naval base and oil platform maintenance facilities availability of operational forecasts essential

Study background

• Set-up of an operational system for the Brazilian Navy to forecast wave propagation and 3D hydrodynamics in the Guanabara Bay.

Tetra Tech: Delft3D-FLOW and Delft-WAVE models

Deltares: FEWS operational system.

Brazilian Navy: field data and model boundary conditions from a regional model.

Complex area (coastline, narrow channel, island) makes it suitable for a Delft3D Flexible Mesh application

Objective DFM pilot case

• Set-up and compare the results of a D-Flow FM model with the conventional Delft3D model

Original Delft3D FLOW

Delft3D FM (a)

• Keeping the same grid and forcing

• Delft3D FM (b)

• New grid, same forcing

Delft3D-FLOW/Delft3D-FM (a) GRID

~200km

Delft3D-FLOW/Delft3D-FM (a) GRID

Hydrodynamic Model

Delft3D-FLOW/Delft3D-FM (a) • 3D model – 5 sigma layers (20% each layer)

Forcing

• Water Level 16 water level (time-series) boundaries based on HYCOM water level hourly

results (from Brazilian Navy Model)

• Wind and Pressure Wind (u and v comp.) and Pressure – spatial varying

• Discharge Boundaries 9 discharge (time-series) boundaries based on mean discharge values

• Thin dams / Dry points

• Observation Points

Hydrodynamic Model

Delft3D-FM (b) • 3D model – 5 sigma layers (20% each layer)

Forcing

• Water Level 23 water level (time-series) boundaries based on HYCOM water level hourly

results (from Brazilian Navy Model)

• Wind and Pressure Wind (u and v comp.) and Pressure – spatial varying

• Discharge Boundaries 9 discharge (time-series) boundaries based on mean discharge values

• Thin dams / Dry points

• Observation Points

Guanabara Bay - Delft3D-FLOW/Delft3D-FM (a) grid FM Delta Shell Interface

Delft3D-FLOW/Delft3D-FM (b) GRID

FM Delta Shell Interface

High resolution – bay entrance/ navigation channels

Low resolution – adjacent coastal

zone

RESULTS

TIME SERIES

• Water Level Measurements were compared with all the scenarios (FLOW, FM (a) and FM (b)).

• Water level results from FLOW x FM (a) were compared, for the same station.

• Surface and bottom velocity results from FLOW x FM (a) were also compared, for the same station.

MAP RESULTS

• Delft3D-FLOW x Delft3D-FM (a)/ surface velocity

• Delft3D-FLOW x Delft3D-FM (b)/ surface velocity

Comparisons with Water Level

Measurements

Delft3D-FLOW

Delft3D-FM (a)

Delft3D-FM (b)

Delft3D FLOW x Delft3D-FM (a)

Water Level

Velocity (surface)

Delft3D FLOW x Delft3D-FM (a)

Velocity (bottom)

Delft3D FLOW x Delft3D-FM (a)

Delft3D FLOW x Delft3D-FM (a)

Map Results

• The main

differences are

observed close

to irregular

coastal areas,

narrows and

islands.

Map results

Vectors are very

similiar

(magnitude and

direction)

Differences in eddy formation

Delft3D FLOW x Delft3D-FM (b)

FLOW

FM (b)

• Stronger velocities nearby the bay entrance;

• Differences on eddy formation;

Dry Points

defined on

Delft3D-FLOW

Dry Points

NOT defined

on Delft3D-FM

WITHOUT dry points/ thim dams/ “.pli” files

WITH dry points/ thim dams/ “.pli” files

Conclusions

• The tests in Guanabara Bay showed a good agreement between Delft3D-FM results and measurements and also with Delft3D-FLOW results;

• Delft3D-FM grid represent a great option to solve the Guanabara Bay complex coastline with a high resolution, without a large number of cells outside the bay. However, the grid needs be further improved in some regions;

Conclusions

• During the pilot case some difficulty was found and some functionalities that did not work. Tetra Tech team used more the old interface than the Delta Shell FM because some functions did not work in the new one. All of the steps that Tetra Tech team could not solve were resolved by the ambassadors;

• Tetra Tech users felt that Delft3D-FM interface still have to be adjusted (more automated functions / less manual), mainly in the part of grid generation, to reduce the time of grid construction;

Conclusions

• It is Tetra Tech conclusion that Delft3D-FM is a great improvement for Delft3D, and we are very interested in continue the partnership with Deltares in the final development of the system;

• Congratulation to all Deltares development team!!!

Thank you

Fernanda.Fiedler@tetratech.com

Eduardo.Yassuda@tetratech.com

Freek.Scheel@deltares.nl