MEng Civil Engineering

The unit provides an introduction to the principles of fluid dynamics in an applied engineering context. The unit is divided into four parts.
The first part introduces mass, momentum and energy conservation laws and their mathematical statement for steady-state flows. Applications are presented to flows with non-uniform velocity distributions. The unsteady form of the continuity (mass conservation) equation is also introduced and applied to tank emptying/filling problems.
The second part of the unit covers the theory of pipeflows with application to simple water distribution systems. The theory of uniform open channel flows is also presented.
The third part covers dimensional analysis and the theory of similitude, providing the theoretical framework to analyse physical problems using scale models.
The fourth part introduces pumps and turbines. After a general introduction to their classification, the unit focuses on the calculation of duty points and power consumption of pumps. Some elements of the theory of rotodynamic machines are also provided.

1. To introduce mass, momentum and energy conservation laws for fluid flows and demonstrate their application to basic fluid mechanics problems with uniform and non-uniform velocity profiles;
2. To introduce the basic concepts of flows in pipes and open channels with applications to water supply and drainage system design;
3. To provide a general foundation for dimensional analysis as a tool for design of experiments, interpretation and presentation of experimental results, identification of dimensionless numbers and their significance, and definition of dimensionless relationships;
4. To provide working knowledge of the theory of similitude for predicting prototype performance from scale model tests;
5. To provide an overview of the characteristics and ranges of application of different types of pumps and turbines;
6. To provide working knowledge of the operating principles and performance characteristics of pumps.

The unit is structured into four parts:

(1) Mass, momentum and energy in non-uniform and time-varying flow:
Calculation of flow rate and momentum flux by integration; determination of forces on immersed bodies in a moving fluid; application of Bernoulli's equation (with losses) to flow measurement and tank emptying/filling; calculation of energy losses in non-ideal flow.

(2) Flow in pipes and open channels:
Calculation of head losses in pipes and pipe networks; flow rate and pump sizing calculations. Determination of normal depth and hydraulic radius in uniform flows in open channels; application of Manning's equation.

(3) Dimensional analysis:
Introduction to dimensions and units; Buckingham's Pi theorem and applications to non-analytical problems. Applications of the theory of similitude: use of scale models to test prototype designs.

(4) Pumps and turbines:
Calculation of pump and turbine efficiency. Classification of pumps and turbines.  Determination of duty points for single pumps and for pumps in series and parallel; determination of duty points and required rotational speed for variable speed pumps. Derivation and application of Euler’s turbomachine equation. Determination of optimal rotational speed for a Pelton turbine.

There is one laboratory exercise:

Centrifugal pump lab

The objective of this laboratory is to determine the characteristics of centrifugal pumps under different conditions. The experiment demonstrates the case of a single pump working at full speed and half speed, and the case of two pumps working in series or parallel.

Other - assessed tutorial work

Marked laboratory reports and coursework will be returned with comments where appropriate. Common problems in coursework will be highlighted in lectures and tutorials. Full worked answers and video solutions to exam-type questions will be available on Blackboard. The lecturer will be available to discuss individual problems.

Note: exams are for assessment not feedback.