The Hydrodynamics Laboratory is equipped with a wide range of facilities to simulate waves and their influence on the natural and built environment. Our state-of-the-art facilities can be used to experimentally generate waves, winds and currents in two or three dimensions. Waves propagating in one direction are typically simulated in our 4 wave flumes, while waves propagating in multiple directions are generated in our 2 wave basins. Each wave generation facility is fitted with a modern active-absorption control system, enabling the realistic representation of ocean wave conditions. 

Deep-water wave basin 

The deep-water wave basin at Imperial College London is one of the largest directional wave basins in the UK. It has a plan area of 20m by 12m with an aspect ratio that allows for accurate reproduction of the directional properties of realistic waves. This facility has a maximum operational water depth of 1.5m and a movable bed system which allows water depths as low as 0.5m to be achieved. The wave-generation process is controlled through a bank of 56 numerically controlled flap-type wave paddles. These paddles allow state-of-the-art experimental conditions to be generated, including directional sea states with frequency dependent spectra. The centre of the basin has a 3.5m deep core measuring 1.2m by 1.2m – ideal for modelling catenary moorings and other deep water operations. The deep-water wave basin has been used in pioneering experiments in wave-structure interaction and metocean studies in the broad fields of oil and gas, marine renewables and offshore wind energy as well as fundamental studies of wave statistics.   

Shallow-water wave basin 

The shallow-water wave basin is a specialised facility for coastal research. It comprises of 8 large piston-type wave paddles and a perforated parabolic beach enhanced with geotextile material. Its plan dimensions are 26m by 6m and the water depth at the paddle can vary between 0.4m and 0.8m. The bed of the basin is equipped with mounts that allow the installation of a wide range false beds. The adjustable bed can be flat, sloping (1:250-1:5) or complex (e.g. trapezoidal) and can be fixed or mobile (sand). The wave basin can generate long- and short-crested waves as well as currents. The facility generates currents as a recirculation flume using a constant head with natural flow. It is also equipped with a high-speed, digitally controlled carriage that spans the full width of the tank. As such, this versatile facility can be used as a wave basin to study combined wave-current wave basin, a towing tank with maximum depth of 1m or a recirculating flume. Present research in the shallow water wave basin includes coastal hydrodynamics, wave-structure interaction (breakwaters and harbours), testing of marine renewable devices as well as beach evolution. 

Long flume 

The long flume is equipped with four large flap type wave paddles. It is 1.2m deep, 2.6m wide and 55m long. The digitally controlled wave paddles operate with active force-feedback absorption, allowing for the generation of large, high quality, unidirectional regular and random wave fields. The comparatively large size of the flume makes it ideal to undertake experiments on wave energy devices and other floating structures – such as offshore wind turbines – at scales of approximately 1:60. Furthermore, a rail-mounted carriage is installed above the flume and can be used to tow objects – this is particularly valuable when examining effects such as the wake developed behind a moving body. 

Coastal flume 

The coastal flume is a 23m long, 0.6m wide facility, designed to reproduce waves in intermediate and shallow water depths. The flume is equipped with a piston-type wave paddle and can be operated in a wide range of water depths (0.4-0.7m) and incident conditions (regular, random and custom). The wavemaker can accurately represent waves generated in the intermediate and shallow water depth regime and uses force-feedback, active absorption technology to minimise reflections. The waves can propagate over the original flat bed configuration or over custom built bed slopes of variable angles. At the downstream end, the waves are effectively absorbed by an adjustable, perforated beach which is enhanced by a 3D geotextile. Present research focuses on the accurate generation of random waves in the nearshore environment, the evolution of waves in finite water depths (nonlinear interactions and wave breaking), the design of coastal structures and sediment transport. Measurements that are typically performed in this flume include: water surface elevation at multiple locations along the flume, wave run-up and overtopping, forces and pressures on coastal structures, wave kinematics, wave breaking, sediment transport and beach evolution. 

Double-ended flume 

The wind-wave-current flume is a unique facility with wave boards located at opposing ends of the 27m long tank, an overlying wind tunnel and a re-circulating current. The wave boards are fully controlled numerically and operate using state-of-the-art force feedback. As such, these paddles can absorb and generate wave energy, making it a novel facility for the study of wave power take-off. This facility has been instrumental in much of the group’s work relating to extreme ocean waves, wave-current interactions and wind-wave interactions. 

Wave evolution flume 

The wave evolution flume is a bespoke facility designed to examine the properties of waves as they propagate from deep water into shallow water. To achieve this, the 60m long, 0.3m wide flume is fitted with sloping beds of variable angles that allow waves to propagate from a water depth of 0.7m to the shoreline. Typical slopes employed in experiments range from 1:250-1:10 while the full length of the flume is instrumented with a large number wave gauges, pressure transducers and radars to measure wave evolution over large distances. The glass walls allow visual access for advanced imaging techniques, such as particle image velocimetry, and the reliable measurement of wave kinematics. Similar to the other flumes the laboratory, the waves are generated using a force-controlled flap-type wave maker. The research undertaken in this flume is particularly useful for studying wave evolution in the shoaling and surf zones, predicting near-shore wave conditions for wave energy conversion, testing the efficiency and survivability of coastal structures as well as sediment transport and beach evolution. 

Large recirculation flume 

In contrast to many current flumes, this facility in the Hydrodynamics Laboratory is continuously fed with a constant head to reduce the turbulent kinetic energy of the flow. This gives the researcher the flexibility to create the flow conditions they require, a recent example being the introduction of a bed structure to create realistic oceanic turbulent kinetic energy for a tidal turbine investigation. The flume has a variable width, adjustable in 0.3m intervals up to a maximum 1.2m and a working length of 2.4m. The combination of the width, volume and a maximum flow rate of 0.3m³/s allow for full flow-depth control. 

The section is involved in a number of teaching activities. To help understanding of complicated problems, the section runs demonstration labs to give students a visual understanding of the problems they are trying to solve.

Teaching demonstration equipment

This has a wide range of flumes, Ahlborn tanks, flow visualization tanks, and pipe flow experiments that are used to demonstrate basic principles in Fluid Mechanics to the undergraduate engineers.