"..the MIKE system proved to be extremely user-friendly and efficient ....providing more time to consider the science"
This enthusiastic endorsement was made by Oliver Jones at the recent DHI Software User Group Meeting (UGM) in the UK. Oliver is working toward his PhD at the University College London (UCL) and has, in the course of his studies, been using many different modelling tools. His collaboration with DHI and use of their technology has enabled him to focus much more on the scientific applications rather than monotonous modelling tasks.
"I have applied the new MIKE 21 FM Series to two cases in U.K. waters. The first was in the construction of a detailed hydrodynamic model of the Solent region and the second in a fully coupled hydrodynamic, wave and morphological model of the Bristol Channel", says Oliver Jones and continues:
"The Solent study was a collaborative project between ABPmer, DHI and Microsoft, and was being used as a technical test case for the launch of Microsoft’s new 64 bit operating system. We selected the Solent region because of the variety of coastal environments that exist there and also for its importance as a shipping hub and haven for marine recreation. Having the capability of locally refining dynamic and complex areas in the flexible mesh system was extremely useful. The model performed well, especially in the many inter-tidal zones. The model was also tested with a dynamic land boundary in which the extent of the wet zone was dictated by real coastal topography rather than a fixed boundary. This approach requires high resolution inter and supra-tidal topography and can cost extra computational time. However, if sufficient detail is available, the near-shore region can be much more accurately resolved and the results are available in a form that provides eye-catching presentations and animations. Also useful in the Solent study, was the post-processing capability of the MIKE system which proved to be extremely user-friendly and efficient. The system provides quick access to the results which can be presented in a clear and informative way, providing more time to consider the science.
The second application is in the Bristol Channel, a large macro-tidal estuary in the Western U.K. My main interest is in understanding the morphological relationship between regional sediment transport and a linear sandbank in the north of the region. The position of the sandbank appears fixed to a prominent coastal headland and its role as a marine aggregate resource is the subject of extensive environmental litigation and concern. A combination of extreme wave events and large tides provides the backdrop to an extremely complex modelling environment. The biggest challenge of the project involves resolving the varying spatial and temporal scales of the contributing processes. At one level, the regional sediment transport is driven by tidal currents and on another, by strong local wave-driven currents. The two interact to produce highly complex patterns of transport. Superimposing the effect of storms and meteorological forcing adds further complication. The modelling strategy that has been devised, first, attempts to isolate and identify the contributing process, then, ensures that the model setup is capable of incorporating and reproducing them. Although the flexible mesh approach provides local refinement, capturing the complete spectrum of processes on this spatial scale is highly grid dependent and therefore has required numerous stages of refinement and iteration. The system has demonstrated competency in simulating wave induced currents and wave-current interaction. Wave blocking, which is common in the Bristol Channel, has caused minor numerical problems. However, these have been easily resolved by adjusting wave-blocking factors effectively cut off the high frequency wave energy causing the problem.
The work is in progress and forms the bulk of my Phd research to be completed by next year. I look forward to updating you with any new insights"
Download the full presentation, "ABPMer/UCL: Examples of flexible mesh modelling in UK waters", that Oliver Jones gave at the UGM, please click the link on the right hand side.
For more information about the DHI Software technology applied, please feel free to contact: Erland Rasmussen ebr@dhi.dk