Landslides impact reduction effect by using honeycomb-hole submarine pipeline

Submarine landslide impact is a threatening load in the service lifecycles of deep-sea pipelines and has attracted tremendous attention in scientific research and engineering construction. However, no effective deep-sea pipeline protection measures are applied in engineering practice. In this paper, a submarine pipeline with honeycomb holes is proposed. This pipeline design standard is quantified by defining three parameters. Based on the computational fluid dynamics method, numerical calculations of common circular and new cross-section pipelines that are impacted by landslides were systematically investigated using a low-temperature rheological model. The results demonstrate that the higher is the Reynolds number, the larger the resistance reduction effect, and the peak drag force on the pipeline with honeycomb holes can be reduced by 20%. Simultaneously, the vibration effect of the pipeline that is caused by the lift force can be effectively suppressed. Further, the relevant resistance reduction mechanisms are revealed using the theories of boundary layer separation and turning point delay. This paper proposes a preliminary design concept of a submarine pipeline with honeycomb holes that effectually reduces the impact of landslides, sand waves and bottom currents on the pipeline to protect the operational safety.