This document summarizes the use of MIKE software at Queen's University Belfast for teaching and research purposes. It discusses how MIKE is used in various courses to model coastal engineering processes and tidal energy. It also describes several research projects using MIKE to model wave energy converter arrays, sewage outfall impacts, horse mussel larval transport, and more. The document emphasizes that MIKE provides an easy interface for students to learn modeling while also serving as a valuable research tool.

1. Teaching & Research with
MIKE by DHI @
Queen’s University Belfast
Dr Björn Elsäßer Dipl. Ing. CEng
13th May 2014

2. School of Planning, Architecture and Civil Engineering
• Established 1845 as Queen’s College,
• More than 17,000 students and 3,500 staff,
• Part of Russell Group of Universities,
• SPACE has 60 staff and 160 students starting
each year
About Queen’s University Belfast

3. School of Planning, Architecture and Civil Engineering
Marine Renewable Energy @ QUB -
Wave Energy

4. School of Planning, Architecture and Civil Engineering
Marine Renewable Energy @ QUB -
Tidal Energy

5. School of Planning, Architecture and Civil Engineering
MIKE in class
Coastal Engineering & Tidal Energy module
• Demonstration of shoaling, refraction and
diffraction using Mike 21 BW
• Building of a complete tidal model of the
Severn Estuary

6. School of Planning, Architecture and Civil Engineering
• Easy analysis of data without
knowledge of any programming
language
MIKE in class
Tidal Analysis & Prediction Toolbox
• Knowledge &
understanding of student
can be tested !

7. School of Planning, Architecture and Civil Engineering
MIKE in class
Wave hindcast model as 3rd year project

8. School of Planning, Architecture and Civil Engineering
• Importance of southern Atlantic
wave climate on NA
• Good performance of SW model
relative to assimilated data
From student project to PhD project
The North Atlantic Wave model

9. School of Planning, Architecture and Civil Engineering
Sewage outfall impacts in Belfast Lough
Belfast Lough historically eutrophic
£43 m investment in 2006 to improve water
treatment
New wastewater treatment works completed
in 2008
Minimal tertiary treatment prior to discharge
Designed discharge capacity of 900 l/s
Daniel Pritchard Hydrodynamic models as ecological tools
Belfast
Portaferry
Treatment
Works
Outfall

10. School of Planning, Architecture and Civil Engineering
The ‘Briggs Rock Seaweed Culture Project’
Daniel Pritchard Hydrodynamic models as ecological tools
≈ 30 % of N
≈ 1.5 % of P
Possible…
but not experimentally tractable!

11. School of Planning, Architecture and Civil Engineering
Outfall Impacts: Approach
Water samples from the treatment plant
In situ water samples
Seaweed bulk stable isotope samples
Hydrodynamic model development and validation
Simplified plume and processed-based macroalgal
models (Eulerian transport)
Daniel Pritchard Hydrodynamic models as ecological tools

12. School of Planning, Architecture and Civil Engineering
Outfall impacts: Results
Initial dilution is very high
High spatial variability
The model predicts the magnitude of the
nutrient input the right order of magnitude…
… but under predicts on Spring Tides
Daniel Pritchard Hydrodynamic models as ecological tools
Pritchard et al. In review. Marine Pollution Bulletin

13. School of Planning, Architecture and Civil Engineering
Outfall impacts: Results
Stable isotopes
Significant, but small differences
between sites
Daniel Pritchard Hydrodynamic models as ecological tools

14. School of Planning, Architecture and Civil EngineeringLouise O’Boyle
Wave Energy Converter
• Designed to extract energy from waves
• Also interact with local wave climate
Wave Energy Converter Arrays
• Multiple devices deployed in close proximity
• One WEC may positively or negatively influence energy available
for other WEC’s
• Increased scale - increases potential for changes to coastal
processes, sediment transport and ecology.
Changes to Wave Field
• Quantifying changes in wave field numerically facilitates
environmental impact assessments and design of optimum wave
farm layout
• Experimental results required for numerical model validation
Wave Fields around Wave Energy Converter Arrays.
Wave Fields around Wave Energy Converter Arrays

15. School of Planning, Architecture and Civil EngineeringLouise O’Boyle Wave Fields around Wave Energy Converter Arrays.
Potential interaction of a WEC on the surrounding
wave field.
Wave
Scattering
Reflection Diffraction
Wave
Radiation
In order for a device to extract
energy it destructively interfere with
incident waves: wave radiation
How will Wave Farm Interact?

16. School of Planning, Architecture and Civil EngineeringLouise O’Boyle 8/ 21
Experimental Approach
• Experimentally map the wave climate around WEC array
• Use different model types for each interaction effect
• Each tested individually and in 4 array layouts
• Results used for numerical model validation
Wave Fields around Wave Energy Converter Arrays.

17. School of Planning, Architecture and Civil EngineeringLouise O’Boyle 10/ 21
Results – Wave Disturbance (mm)
Terminator Array Configuration
Attenuator Array Configuration
Wavelength = device spacingWavelength > device spacing Wavelength < device spacing
Wave Fields around Wave Energy Converter Arrays.
Sample Results

18. School of Planning, Architecture and Civil EngineeringLouise O’Boyle 13/ 21
MIKE 21 Boussinesq Waves
• Phase resolving – depth averaged
MIKE 21 Spectral Waves
• Phase Averaged
Model Area – Portaferry Wave Basin
• Experiments carried out at Portaferry Wave Basin
• Maximum correlation with experimental data required
• WEC arrays simulated in models of wave basin
• Numerical models validated at wave basin scale
• Subsequently extended to full scale
Surfaceelevation(mm)
Time (s)
Frequency (Hz)
SpectralDendity
Wave Fields around Wave Energy Converter Arrays.
Numerical Representation of WECs

19. School of Planning, Architecture and Civil EngineeringLouise O’Boyle
WEC representation in MIKE 21 SW Model
• WEC represented using ‘Structures’ tool in SW model
• Definition of frequency and directionally dependent
• Reflection coefficient - Kr
• Transmission coefficient - Kt
• Absorption coefficient – Ka = √(1 – Kr
2 – Kt
2)
• Energy balence is altered accordingly at each cell containing a structure.
Fully Reflective Absorbing Obstacle Oscillating Water Column
Kr = 1
Kt = 0
Ka = 0
e.g. Kr = 0
Kt = 0.8
Ka = 0.2
(related to absorption)
Kr = reflected + (Krad /√2)
Kt = transmitted + (Krad /√2)
Ka = Krad
(related to power capture)
Acting over
what
diameter?
Frequency &
directionally
dependant
Wave Fields around Wave Energy Converter Arrays.

20. School of Planning, Architecture and Civil Engineering
WEC presentation in MIKE 21 BW Model
• WEC represented by assigning porosity values to each cell within the
footprint of the device.
• Fully reflective obstacles – porosity = 0, equivalent to ‘land value’
• Absorbing obstacles - porosity = 0.4 or variable porosity
- characteristic unit diameter = 0.01 (laminar)
• Real WEC represented using internal generation lines to simulate the
radiated wave
Louise O’Boyle Wave Fields around Wave Energy Converter Arrays.

21. School of Planning, Architecture and Civil EngineeringLouise O’Boyle
• BW model results based on surface elevation (Boussinesq eqn.)
• SW model results based on wave energy (Action Balance eqn.)
• Therefore it is proposed that a better parameter for cross validation of
models is change in energy content
Comparison of results for single OWC at damping level 3
Wave Fields around Wave Energy Converter Arrays.
Comparison of Results

22. School of Planning, Architecture and Civil EngineeringLouise O’Boyle
Comparison of Array Configuration and Damping Level
• SW model has been validated and can be used to investigate effects of
array layout and damping levels on the wave field
Wave Fields around Wave Energy Converter Arrays.

23. School of Planning, Architecture and Civil Engineering
Horse-mussel larvae in Strangford Lough
Strangford Lough heavily dredged
for queen scallops in the late
1970’s and early 1980’s
Massive decline in Modiolus
modiolus biogenic reefs
Daniel Pritchard Hydrodynamic models as ecological tools
Cultch site
Strangford
Lough
Strangford
Narrows
52 days of simulation
True Lagrangian transport
Full hydrodynamic background
Continuous release, 6 sites, 200
particles per timestep

24. School of Planning, Architecture and Civil Engineering
Horse-mussel larvae: Results
Daniel Pritchard Hydrodynamic models as ecological tools
Elsäßer et al. 2013. Identifying optimal sites for natural recovery and restoration of impacted biogenic habitats in a special
area of conservation using hydrodynamic and habitat suitability modelling. Journal of Sea Research, 77: 11--21.

25. School of Planning, Architecture and Civil Engineering
What is to come:
• LINC -

26. School of Planning, Architecture and Civil Engineering
Conclusions
• Easy user interface allows engineering students to
get into hydraulic modelling quickly
• Excellent research tool – mean to an end!
• Enables colaborative work, where focus is on the
science not on the process
• Improvements to code or additions can be
implemented

27. School of Planning, Architecture and Civil Engineering
For more details see:
• http://www.qub.ac.uk/research-centres/eerc/
• http://tiny.cc/BjoernElsaesser
• https://github.com/dpritchard
• http://dx.doi.org/10.1016/j.seares.2012.12.006
• http://dx.doi.org/10.1016/j.marpolbul.2013.09.046
• http://dx.doi.org/10.1007/978-94-017-8002-5_12