ENCN445-20S1 (C) Semester One 2020

Environmental Fluid Mechanics

15 points

Start Date: Monday, 17 February 2020
End Date: Sunday, 21 June 2020
Withdrawal Dates
Last Day to withdraw from this course:
  • Without financial penalty (full fee refund): Friday, 28 February 2020
  • Without academic penalty (including no fee refund): Friday, 29 May 2020


Description and modelling of turbulence. Near and far field mixing behaviour. Dispersion in rivers, jets, plumes. Outfall design. Introduction to wave theory, including wave dispersion and forces.

Environmental fluid mechanics is a special branch of fluid mechanics associated with the interaction of humans with the naturally occurring fluid bodies – the atmosphere, the oceans, estuaries, rivers, and lakes/reservoirs. These fluid bodies impact on human civilisation in a number of critical ways:

• They present significant risk to humans through extreme events. The recent tsunami in Indonesia in 2004 and Japan in 2011 bear witness to the potential severity of this risk.

• They provide critical resources, namely water to drink, air to breathe and energy for power generation.

Human beings also impact on these fluid bodies:

• We modify these fluid bodies through man-made interventions. Drawing water from rivers for irrigation for example, or building a breakwater in a coastal zone.

• We use them for the disposal of our wastes. There are many instances of this, for example, ocean outfalls of municipal waste or effluent from desalination plants, smokestacks in the atmosphere and discharges from factories into rivers.

Environmental fluid dynamics is a very broad topic and this course can only provide a cursory introduction to it. However by the completion of the course you should appreciate some of the fundamental characteristics of these natural flows – in particular turbulence and wave motion– and you should be able to undertake basic modelling of certain aspects of our interactions with them – in particular the modelling of turbulent mixing in the ocean, rivers and atmosphere and within buildings

This course relies heavily on the fluid dynamics concepts of ENCN242 and ENCN342 and some of the mathematics of ENCN304.

The course is split into three essentially self-contained sections. The first introduces turbulent flow and discusses the problem of turbulent mixing in the environment when the environmental fluid is responsible for the transport and dilution of the effluent – this is known as far field mixing. The second considers one aspect of coastal engineering by providing an introduction to wave dynamics and the impact of ocean waves on the coastline. The third focuses on mixing in the near field where the environment plays a more minor role in the mixing process and the source discharge characteristics are predominant. It covers the canonical fluid flows referred to as jets and plumes as well as considering the flow and properties of air inside buildings.

Learning Outcomes

  • At the conclusion of this course you should be able to:
  • Provide a qualitative description of turbulent flow that includes the ideas of a spectrum of eddies of varying sizes, the energy cascade and turbulent kinetic energy dissipation.
  • Understand the basis of Reynolds averaging, why it is often required to make headway in solving turbulent flow problems, and the closure problem that results.
  • Explain the concept of an eddy viscosity and describe two turbulence models, Mixing Length Theory and the k-ε model, that are based upon it.
  • Understand how far field mixing can be modelled using the turbulent advection diffusion equation and be able to model such mixing using an appropriate model.
  • Provide a broad overview of coastal engineering and explain some of the solutions, both hard and soft, that engineers employ to solve coastal engineering problems.
  • Understand the basic behaviour of ocean waves, including dispersion and group and phase velocity.
  • Understand the transformations that ocean waves undergo as they encounter the coast and be able to predict the result of this interaction.
  • Analyse real wave data to obtain design wave parameters and analyse some of the impacts these waves may have on the coastal environment.
  • Explain the important differences between axisymmetric plumes, line plumes and wall plumes.
  • Model the environment within a room and understand simple methods of natural ventilation.

Course Coordinator / Lecturer

Craig McConnochie


Assessment Due Date Percentage 
Final Exam 65%
Turbulence Project 25 Mar 2019 10%
Coastal Eng. Project 06 May 2019 10%
Jets and Plumes Project 31 May 2019 15%

The assessment for this paper will comprise two components – three projects projects and the final exam. The projects aim to provide you with the opportunity to work through substantial practical problems, putting into practice the analysis and design skills you have learnt. The final exam will focus more on the theoretical aspects of the course where the solution of complex practical problems is not possible due to the limited time available. The breakdown of all of the assessment items is listed below. Please read the following notes carefully.

1. You cannot pass this course unless you achieve a mark of at least 40% in the final exam. A student who narrowly fails to achieve 40% in the exam, may still may be eligible for a pass in the course if they have shown consistently high class attendance and have performed very well in the internal assessment items.

2. All projects must be submitted by the due date. Late submissions will not be accepted. If a student is unable to complete and submit an assignment by the deadline due to personal circumstances beyond their control they should discuss this with the lecturer involved as soon as possible.

3. Students in this course can apply for special consideration provided they have sat the final exam.

4. All projects must be done individually.

Textbooks / Resources

Electronic copies of course materials will be made available through Learn.


This course will be delivered in a traditional lecture format with supporting tutorials that will provide you with activities to reinforce your learning. As classes will be small it is expected that all students will engage actively in the class asking questions and contributing to the discussions.  Attendance at all classes is expected.

As this is a final year elective course it is my expectation that you are a motivated and independent learner. You will seek support from the lecturer as well as from digital and physical resources as you see a need. I expect that you will do additional reading on topics that particularly interest you so that you gain additional knowledge outside that directly covered by the lectures.

Here is a rough guide to the amount of time you should be putting into the various
aspects of this course.

Lectures - 33 hours
Tutorials - 14 hours

Independent study
Course material review - 30 hours
Independent reading and research - 10 hours
Exam preparation - 10 hours
Projects - 60 hours

Total hours - 157

Additional Course Outline Information

Course communication

All communication with the class will be via email or during scheduled class periods.

Indicative Fees

Domestic fee $1,102.00

International fee $5,500.00

* All fees are inclusive of NZ GST or any equivalent overseas tax, and do not include any programme level discount or additional course-related expenses.

Minimum enrolments

This course will not be offered if fewer than 5 people apply to enrol.

For further information see Civil and Natural Resources Engineering .

All ENCN445 Occurrences

  • ENCN445-20S1 (C) Semester One 2020