2021: Muddling Along To A Healthy Year In Dredging

Calendar picture of a sunny dredging site
Calendar picture of a sunny dredging site

Dear readers, I sincerely wish you all the best for this new year. As things are looking positive on the vaccine front, we should keep testing negative this year. There are lots of items and events to look forward. Last year was not quite what we’ve hoped for and wished each other.

I do hope all of you are OK and are still together with your loved ones. I am fortunately in that respect. So, next to the Covid situation, there were a lot of other noteworthy items. Most of them have been featured here on Discover Dredging. My trip to Bangladesh, just before all the lockdown measures. The graduation of Carsten1 and Omar2 that were completely over Teams. Some attention to our Damen Dredging Experience3. And some other items. Did you enjoy the Donald Duck review?4

Opening scene of ‘Muddy Fine Business’ or ‘Success Test’ (Credit: Disney)
Opening scene of ‘Muddy Fine Business’ or ‘Success Test’ (Credit: Disney)

One sad event was, the last issue of Dredging and Port Construction5. We’ve had to say goodbye to our trusted DPC. Although by now, there has been a kind of digital revival on the CEDA Website6. They opened up a section for Industry News, edited by Namrata Nadkarni. It stands out from the other online media covering dredging as there has been some attention to smaller topics, that would normally not get covered. As I think it is a good initiative, I urge you to subscribe and also participate by sending them any noteworthy news items for publication. Not specifically the usual company press releases, but also the more thought provocative opinions and perspectives on the activities of our dredging community. Active participation could make this CEDA Industry News flourish this year.

Announcement of the CEDA Industry News section (Credit:CEDA)
Announcement of the CEDA Industry News section (Credit:CEDA)

Further personal activities within CEDA are the Dredging Management Commission7 and I am looking forward to the exciting new concept for the CEDA Dredging Days8. Will you participate? Also, I already took the course on ‘Dredging for Sustainable Infrastructure’9, but you should keep an eye out on the next instalment, coming soon10.

A continuation from last year on my Discover Dredging will be some more articles on our Damen Dredging Experience. There are still some exhibit left to review and teaser:… There are some new exhibits arriving! Hope to have that covered when the pandemic will fizzle out we can show you around through our museum. And I hope to continue on pump and dredge technology.

Overview of the Damen Dredging Experience
Overview of the Damen Dredging Experience

Currently, there are some students working on their graduation thesis. Their very interesting topics will be highlighted here as well. Some others will start soon. When you are looking for a fun place to have your internship our your graduation, you might consider a visit to our career page11 or contacting Frank Bosman for any opportunities. Although most positions are filled at the moment, later this year we would welcome fresh brains again.

As our offices will be closed for regular work, I will be working from home most of the time. Probably most of you will do likewise. To keep track of the passage of time over the days, you should have a calendar. As a special service to my audience, I was granted the use of a set of beautiful pictures to create a calendar. You can download the file here and with some DIY skills you should have some original wall decoration for this year.

Stay healthy and stay safe. Hope to see you later this year.

Selection of calendar pictures
Selection of calendar pictures

References

  1. Graduation Of Carsten Markus: Designing And Casting Of Impellers, Discover Dredging
  2. Graduation Omar Karam: Rock Cutting The Egyptian Way, Discover Dredging
  3. Selected articles on the Damen Dredging Experience, Discover Dredging
  4. Book Review: Donald Duck A Muddy Fine Business; Artistic Equipment Design; Discover Dredging
  5. The Last Dredging And Port Construction Magazine, The End Of An Era; Discover Dredging
  6. Debut of CEDA Industry News section and monthly newsletter, CEDA
  7. Selected articles on the CEDA Dredging Management Commission, Discover Dredging
  8. Call for Papers for CEDA Dredging Days 2021 issued, CEDA
  9. Book Review: Dredging For Sustainable Infrastructure, Discover Dredging
  10. 2nd Online Course Dredging for Sustainable Infrastructure planned for March 2021!, IADC
  11. Welcome to the best years of your life, Damen

See also

Book Review: Dredging For Sustainable Infrastructure

‘Dredging for Sustainable Infrastructure’ (Credit: CEDA & IADC)
‘Dredging for Sustainable Infrastructure’ (Credit: CEDA & IADC)

Last week, I attended the last sessions of the ‘Dredging for Sustainable Infrastructure’ course, jointly organised by CEDA1 and IADC2. This course is intended to quickly absorb the contents of the book of the same name3 and have a hands on experience of the novel methodology proposed. The book has been written by many different people as members of the participating organisations. As such, it is the condensed knowledge and ideas of the dredging community on a modern approach to infrastructure projects. Although there is a straightforward structure in the book, the publishers initiated courses as an introduction to the book.

Structure of the book (Credit: CEDA & IADC)
Structure of the book (Credit: CEDA & IADC)

As Covid-19 swept across Europe and thwarted the intended live course days, the sessions were postponed and eventually held online. The presenters, Erik van Eekelen, Thomas Vijverberg and Mark Lee did a good job of introducing us to the book and supervise us in the break out working groups. The central storyline of the working groups was the harbour expansion of the fictional port of Tomigo in the fairy land of Quandany. Each of the participants was assigned a role to represent the consultant, the fishing community, the nature conservancy organisations, the power plant etc. A revelation for me from this interaction is how easy you are inclined to be egocentric in the defence of your interests. With just a little more attention to the other interests, there might be much better opportunities for yourself and for the whole of the project.

New harbour basin development at the port of Tomigo (Credit: CEDA & IADC)
New harbour basin development at the port of Tomigo (Credit: CEDA & IADC)

The incentive to produce a book on this novel approach in dredging projects was the UN initiative to launch 17 Sustainable Development Goals4 and the book addresses most of these goals. If we can truly lift the proposed working procedures into an industry standard or even a social mentality, this will be a paradigm shift from where the project was the centre of attention to: ‘Where can nature and society benefit from an economic requirement?’ The next step will be from philosophy to action.

United Nations ‘Sustainable Development Goals (Credit: United Nations)
United Nations ‘Sustainable Development Goals (Credit: United Nations)

The focus of the book is very much on the initial stages of a project: include sustainability on the basis of the design of a project, demonstrating options for sustainable solutions suggestion of sustainable techniques. As a dredging equipment manufacturer5, most of the topics will not affect my daily work. Still, in the work group sessions, it was interesting to see the interaction between the various parties that are involved with the initiation of a project. As a dredge builder4, we usually meet the requirements for the equipment applied. Though, the technical solution to achieve this might be not the most commercial solution. However, the book makes it clear and provides examples, that taking all aspects of a project into account, including social and nature opportunities, the benefits of a sustainable approach of a project might still make a viable business case.

Three pillars of sustainability (Credit: CEDA & IADC)
Three pillars of sustainability (Credit: CEDA & IADC)

The verdict on the book: it is a reference book. And as such it is very tiresome to plough through. However, the course is very enlightening as introductory lectures into the contents. Then the meticulously compiled information starts to live. Don’t depend on the courses alone, also leaf through and note all the valuable tables, graphs and diagrams, especially the guiding boxes that can assist you in setting up your dredging project. It definitely belongs on your bookshelf.

‘Dredging for Sustainable Infrastructure’ in our bookshelf
‘Dredging for Sustainable Infrastructure’ in our bookshelf

References

  1. CEDA and IADC launches new ‘Dredging for Sustainable Infrastructure’ Course, CEDA
  2. Online Course ‘Dredging for Sustainable Infrastructure’, IADC
  3. Dredging for Sustainable Infrastructure, CEDA&IADC
  4. The 17 goals, United Nations
  5. Damen Dredging Equipment, Damen

See also

IADC Young Author Award for 1DH Hopper Loading Model of Jordy Boone

Jordy Boone receives the IADC Young Author Award at the CEDA Dredging Days

OK, one last time we will revisit the CEDA Dredging Days. There was so much to see and experience, that there could be some more posts about them. However, daily life already demands more of my focus and there are fun facts to tell about them also. The conclusion of this series is about a well-deserved IADC award to Jordy Boone. Both, because he did write a terrific article and we will read more about it in the Terra et Aqua journal soon enough.

So, why was his article and presentation so special? Hopper loading is one of the key process components in the production cycle of a trailing suction hopper dredge. And therefore there is a lot of interest in this subject. Countless articles and numerous experiments have been performed on this topic, resulting in a lot of different hopper models. Traditionally a literature review starts with Camp (1936). And there are a lot of models that build on that approach. Camp and the derived models are similar to the Lagrangian approach, where they follow the trajectory of a single particle.

Basics and relations of Camp and derived models

A whole different approach is to follow Euler and fix the frame of reference. The contents of the system has to be modelled as a continuum. Ground breaking work has been done by van Rhee. He modelled the hopper in a 2D environment and based a more comprehensive 1DV model on that. Others have followed up and so does Jordy Boone.

Van Rhee and similar ‘Euler’ models

Other approaches don’t take any physics in their modelling, but consider the hopper as a process block in a control system. At the moment they are only useful for monitoring and controlling an existing system, they don’t have a predictive value, yet.

Control system models

In this overview, we can see, that the 1DH Boone model is part of the Euler family. Normally solving multi-dimensional 2D and 3D Euler problems tend to be slow. Van Rhee already pointed this out and part of his PhD. thesis was the presentation of a more comprehensive 1DV model. Basically a column cross-section through the hopper. Mixture would be deposited on the bed and water flows up and out of the system. Where that model does lack the influence of the density current, Boone literally upended this simplification by using horizontal strata in the hopper. Here, the mixture section can incorporate the horizontal density current conditions. This will give correct mass and momentum equations. Vertical exchange processes are than calculated by closure relations.

Comparison van Rhee and Boone

On top of the cake, Boone also verified his approach in laboratory experiments and prototype measurements. As his manuscript is also well written and accessible, he rightfully received the IADC Young Authors Award. Keep up the good work Jordy, we hope to see more interesting work from you.

Jordy Boone presenting his 1DH model at the CEDA Dredging Days

References

Camp T. R. (1936). ”A study of the rational design of settling tanks.” Sewage Works Journal 8(5), pp, 742-758

Miedema, S.A., Vlasblom, W. (1996). ”Theory of Hopper Sedimentation”. 29th Annual Texas A&M Dredging Seminar, New Orleans: WEDA

Van Rhee, C. (2002). ”On the sedimentation process in a Trailing Suction Hopper Dredger”. PhD thesis, TU Delft, the Netherlands

Braaksma, J., Klaassens, J. B., Babuska R., de Keizer, C.(2007). ”A computationally efficient model for predicting overflow mixture density in a hopper dredger”. Terra et Aqua, 106, pp. 16-25

Spearman, J. (2013) ”TASS Software – User Guide for TASS version 4.0”. HR Wallingford

Jensen, J.H., Saremi, S.(2014). ”Overflow concentration and sedimentation in hoppers” J. Waterw., Port, Coast. Ocean Eng., ASCE, 40

Konijn, B.J. (2016). ”Numerical simulation methods for dense-phase dredging flows”. PhD thesis, Universiteit Twente, the Netherlands

J. Boone, J, de Nijs, M.A.J., (2017) “1DH Modeling of Transport and Sedimentation Inside a Hopper of a Trailing Suction Dredger” CEDA Dredging Days 2017
Note: Not available online yet. Depending on publication by CEDA.

See also

Hopper Loading: What Happens Beneath the Surface

Overview of hopper loading models by Ben Sloof
Nice report with an overview of the various hopper loading models