Research: Hydraulics

The hydraulics group carries out research in the following areas:

• Open channel hydraulics
• Pipe hydraulics
• Flow past hydraulic structures
• Oceanography & ocean engineering
• Flow of human crowds

Refer to the group's national competitive and industry grants and research publications.

Open Channel Hydraulics

We do research on the nature of frictional resistance and the measurement of flow, and the equations and computational methods for flows and floods. Recent projects have included developing better formulae for calculating flow rates from stream gauging measurements, correcting for unsteady effects in stream gauging, the effects on flood levels of obstacles in streams, methods for calculating resistance coefficients from stream gauging measurements, a comparison of modern system or black-box models for flood propagation, and overland flow in irrigation bays.

Pipe Hydraulics

We do research on the nature of frictional resistance and the measurement of flow in pipes, and the equations and computational methods for flows in pipes. Recent projects have included a re-examination of the results of Nikuradse and Colebrook and White to determine rather more convenient friction laws, and the nature of measurements of flow in pipes, showing that some modern techniques such as acoustic travel time methods are inadequate.

Flow Past Hydraulic Structures

In this area we have a greater interest in structures in open channels. We have conducted a review of formulae for flow over sharp-crested weirs, broad-crested weirs, and underflow gates. An experimental and computational study has been made of flow over broad-crested weirs and railway embankments, which has obtained methods and discharge coefficients for use in two-dimensional computational programs. This made use of a higher-order Boussinesq equation that allows flow to pass through critical.

Oceanography & Ocean Engineering

The large-scale structure of eddies and currents in coastal regions is dependent on the rotation of the earth. Work is being done to determine how in a well-mixed coastal environment eddies interacting with the rotation of the earth influence the structure of coastal currents. Over many years the group has also had an interested in water waves and their effects on coasts and on maritime structures. In particular the solutions of steady waves of propagation and standing waves and the forces they cause on structures are of interest.

Flow of Human Crowd

The continuum mechanics of the flow of pedestrians is not based on the Navier-Stokes equations of fluid flow but an established set of partial differential equations based on simple well-established rules governing crowd motion. Research in the Department is directed at using these equations to understand the motion of crowds in dangerous situations with a view to improving the safety of crowds in specific situations. Other studies, often of historical events in the medieval or ancient worlds, are also undertaken. These include studies of the Battle of Agincourt, 1415 and Xenophon's March 400BC.