Propulsion Performance of the Full-Active Flapping Foil in Time-Varying Freestream

Applied Sciences

卷:10

Lishuang Jia¹  Yufeng Qin¹  Jian Shi¹  Zhanfeng Qi¹  Jingsheng Zhai² 

[1] National Ocean Technology Center, Tianjin 300112, China;

[2] School of Marine Science and Technology, Tianjin University, Tianjin 300072, China;

关键词: full-active flapping foil;    time-varying freestream;    propulsion performance;    hydrodynamic character;   

DOI  :  10.3390/app10186226

来源: DOAJ

【 摘 要 】

A numerical investigation of the propulsion performance and hydrodynamic characters of the full-active flapping foil under time-varying freestream is conducted. The finite volume method is used to calculate the unsteady Reynolds averaged Navier–Stokes by commercial Computational Fluid Dynamics (CFD) software Fluent. A mesh of two-dimensional (2D) NACA0012 foil with the Reynolds number Re = 42,000 is used in all simulations. We first investigate the propulsion performance of the flapping foil in the parameter space of reduced frequency and pitching amplitude at a uniform flow velocity. We define the time-varying freestream as a superposition of steady flow and sinusoidal pulsating flow. Then, we study the influence of time-varying flow velocity on the propulsion performance of flapping foil and note that the influence of the time-varying flow is time dependent. For one period, we find that the oscillating amplitude and the oscillating frequency coefficient of the time-varying flow have a significant influence on the propulsion performance of the flapping foil. The influence of the time-varying flow is related to the motion parameters (reduced frequency and pitching amplitude) of the flapping foil. The larger the motion parameters, the more significant the impact of propulsion performance of the flapping foil. For multiple periods, we note that the time-varying freestream has little effect on the propulsion performance of the full-active flapping foil at different pitching amplitudes and reduced frequency. In summary, we conclude that the time-varying incoming flow has little effect on the flapping propulsion performance for multiple periods. We can simplify the time-varying flow to a steady flow field to a certain extent for numerical simulation.

【 授权许可】

Unknown