Journal of Bionic Engineering

Volume 14, Issue 4, October 2017, Pages 770-780

Naga Praveen Babu Mannam1, Parameswaran Krishnankutty1, Harikrishnan Vijayakumaran1, Richards Chizhuthanickel Sunny2

1. Ocean Engineering, Indian Institute of Technology Madras, Chennai 600036, India
2. Texas A&M University, College Station, TX 77840, USA

Abstract  The use of biomimetic tandem flapping foils for ships and underwater vehicles is considered as a unique and interesting concept in the area of marine propulsion. The flapping wings can be used as a thrust producing, stabilizer and control devices which has both propulsion and maneuvering applications for marine vehicles. In the present study, the hydrodynamic per-formance of a pair of flexible flapping foils resembling penguin flippers is studied. A ship model of 3 m in length is fitted with a pair of counter flapping foils at its bottom mid-ship region. Model tests are carried out in a towing tank to estimate the propulsive performance of flapping foils in bollard and self propulsion modes. The same tests are performed in a numerical environment using a Computational Fluid Dynamics (CFD) software. The numerical and experimental results show reasonably good agreement in both bollard pull and self propulsion trials. The numerical studies are carried out on flexible flapping hydrofoil in unsteady conditions using moving unstructured grids. The efficiency and force coefficients of the flexible flapping foils are determined and presented as a function of Strouhal number.

Key words： biomimetic propulsion      flapping foil      penguin locomotion      Strouhal number      tandem arrangement      thrust coefficient 

Full text is available at http://www.sciencedirect.com/science/article/pii/S1672652916604420