A methodology for designing test models of the impact of submarine debris flows on pipelines based on Reynolds criterion

Recently, predicting accurately the impact of submarine debris flows on pipelines has attracted much attention in ocean engineering. To address this problem, a small-scale model test based on analysis of the Reynolds number is usually employed. However, in the design of the test model, researchers have seldom considered the applicability of the Reynolds number and the rheological model of the debris flow, which had led to the following problems: (1) a large difference in the Reynolds number occurs between the test model and the engineering prototype, and (2) the shear rate of the rheological model exceeds the applicable scope. Hence, a methodology to determine the model dimension to satisfy both the rheological model and Reynolds criterion is proposed, in which two formulations expressing the design size of the test model and the design impact velocity of debris flow are established, respectively. Further, the influence of the rheological model on the design test model of the interaction between submarine debris flows and pipelines is briefly discussed. Finally, the optimal design value of the model size and impact velocity of debris flow is achieved and recommended to the models in the laboratory test and the numerical computation.