Project Description
Buckle initiators (BI) are used to support subsea pipelines which are designed to buckle to release stresses in the pipeline. The free-spans formed from BIs will be subject to local scour and potentially vortex-induced-vibration. This project aims at assessing the scour process under free-spans formed from BI and how to reduce the impact of local scour.
Part (1): Two UWA final year students worked on this project in 2019. A model test was conducted using a water flume at UWA with a 12 m long 40mm diameter model pipe. The pipe was laid on a sand bed with the upstream end elevated to simulate the free span next to a buckle initiator. The flow direction was in parallel to the pipe. The test showed that no significant scour happens around the touchdown point in this test. Therefore the length of the free span did not change. This demonstrates that the flow with shallow attack angle will not contribute to the elongation of free spans. The results were presented by Prof. Fraser Bransby in 2019 AOG.
Part (2): Some further tests will be conducted using the Large O-tube Facility at UWA to test larger attack angle flow conditions. It is expected that the test results will allow us to observe how free-span evolves due to local scour. The test results will be able to help to assess the impact of free span next to a buckle initiator.