O-Tube
The large O-Tube, which is a closed-loop flume with a base of seabed soil. The cross-section of the flume is 1 m wide by 1 m tall, and the working section is 17 m long. The O-Tube motor is able to generate currents in excess of 3 m/s and wave velocities of up to 2.5 m/s (across periods of 5-15 s). The facility also includes a smaller O-Tube (approximately 5 times smaller in each dimension) which is used for complementary experiments.
Experiments in the O-Tubes provide observations of seabed behaviour during cyclones which could not otherwise be made, as well as fundamental insight into sediment transport and on the loading of infrastructure such as pipelines. For example, the O-Tube experiments allow direct measurement of the forces applied to a pipeline by cyclonic waves with up to 1 in 1000 year return periods. Meanwhile, the changing topography of the seabed is captured by digital imaging methods including binocular infra-red scanning.
Facility Specifications
- Overall length: 24.0m
- Overall breadth: 7.8m
- Height of test section: 1.4m
- Breadth of test section: 1m
- Length of test section: 17.6m
- Maximum steady currentvvelocity: 3m/s
- Peak oscillatory velocity at 5s period: 1m/s
- Peak oscillatory velocity at 13s period: 2.5m/s
- Regular, irregular oscillatory flow (combined with current)
- Sand bed: 0.8m deep, 1m wide and 14m long
- Two instrumented model pipelines (200mm and 50mm diameter) with load or displacement control
Previous Research Projects
- Developing better design guidance about role of field joints in initiating pipeline scour for trunklines
- Erosion tests to measure threshold velocity
Current Projects
- Hydrodynamic load on underwater objects/vehicles and stability assessment
- Vortex Induced Vibration (VIV)
- Sediment transport under various flow conditions
- Local scour assessment around subsea structures
- Validation of scour protection
- Rock berm performance
- Assessment of marine growth on hydrodynamic loads and VIV
