Effect of fish swimming on the stability of flow fields inside the pipeline

Abstract

Hydraulic machinery and various pipeline systems will commonly be infiltrated by many aquatic creatures, and the aquatic community causes important impacts on the flow field, fluid stability inside the pipeline, and the performance of the hydraulic machinery. In this paper, the research about three-dimensional numerical simulation of fish swimming inside a pipeline is conducted, and lattice Boltzmann method is used to complete the flow field solution, where an immersed boundary method based on multi-direct forcing scheme is implemented to achieve the fluid-solid coupling. The fish swimming will be realized by using a time-dependent harmonic oscillation combined with surface vertices. The analysis of the velocity, flow field and vorticity distribution at different moments of fish swimming reveals that the fish passing through the pipeline causes a significant influence on the internal flow field, and the stability of the fluid inside the pipeline. The research in this paper provides referential significance to the operations of hydraulic machinery and pipeline systems in environments containing aquatic community.