As one of the typical negative factors affecting the vortex structure and flow characteristics of hydraulic machinery, the TLV has a non-negligible impact on the energy performance. In order to improve the utilization efficiency of hydraulic machinery in marine energy, the parallel grooves structure is proposed and applied to the NACA0009 hydrofoil. Subsequently, an exhaustive numerical analysis is carried out adopting the SST k-ω turbulence model, and the effects of the position and spacing on the suppression effect and flow characteristics are investigated. The presence of the parallel grooves leads to a decrease in the lift-to-drag ratio of the hydrofoil within 5%, but it can effectively suppress the development of TLV and reduce the area of TLV. The parallel grooves destroy the structure of PTLV and STLV, and the spacing and position have a greater influence on the flow characteristics of the hydrofoil. In order to take the TLV suppression effect and the energy performance of the hydrofoil into account, the L3T1 structure is recommended.

This paper investigates the immersed forces on a fish surface during carangiform locomotion. Numerical simulations were conducted and validated to produce the immersed forces on the surface of the fish. The temporal dynamics of the immersed forces for the steady states of the fish swimming is analyzed with a comparative study based on different fish geometries and motion coefficients. The results demonstrated that under steady undulating, the immersed forces are periodically oscillating, whose magnitudes vary across the fish body. Large forces focus on the edges of the tail tips and the head of the fish during swimming, which are also the regions showing with large vorticities in the fluid. Based on the force distribution, it can be inferred that the source of the propulsion for carangiform is mainly from the rear part of the fish.

Preventing Chronic Disease (PCD) is a peer-reviewed electronic journal established by the National Center for Chronic Disease Prevention and Health Promotion. PCD provides an open exchange of information and knowledge among researchers, practitioners, policy makers, and others who strive to improve the health of the public through chronic disease prevention.

This paper investigates the hydrodynamics of a bent elastic tube with an instantaneously deformed wall using an Arbitrary Lagrangian-Eulerian finite element method. The study reveals that the tube deforms continuously with the fluid’s progression, exhibiting diverse deformation patterns. The flow patterns do not adhere to Poiseuille’s profile, with higher velocities detected on the inner side of the bent region during deformation. The results deepen insights into hydrodynamics within bent elastic tubes, and bring significance for the design of curved pipelines.