Numerical study on the effects of a semi-free and non-uniform flexible filament in different vortex streets

Journal Tittle: Acta Mechanica Sinica

Article Tittle: Numerical study on the effects of a semi-free and non-uniform flexible filament in different vortex streets

Author: Liang Liu，Guoyi He，Xinyi He，Qi Wang，Longsheng Chen

Novelty/impact/significance

1.Proofed that the value of the drag coefficient is at a minimum when the flexibility of the filament increases linearly along the length of the filament.

2.Provided new insights into the role of non-uniform flexibility during the process of fish movement and provide a valuable reference for the design of bionic underwater vehicles.

Scientific question

The impact of the non-uniform stiffness on the swimming performance under biologically relevant conditions.

Key of how

1.We set up three different flexible distribution modes for a semi-free filament and compared the motion performance of different flexible distribution modes through numerical simulations.

2.Using the immersed boundary method to solve the fluid-structure interaction problem in the physical model.

Major points

1.The motion state of the filament will alter with a change in the flexibility of the filament, from moving in the vortex street to moving on the side of the vortex street.

2.In the Bénard-von Kármán (BvK) vortex streets, the drag coefficient of the filament increases  as the flexibility of the filament increases, and the value of the drag coefficient is at a minimum when the flexibility of the filament increases linearly along the length of the filament.

3.At 85% - 90% of the filament length (starting from the leading edge), the flexibility of the filament begins to increase significantly, and the filament can obtain its best propulsion performance.

Funding of the work

1.National Natural Science Foundation of China (Grant No. 11862017 )

2.National Natural Science Foundation of China (Grant No. 11462015)

3.National Natural Science Foundation of China (Grant No. 61963029)

Please go to the website to read this article:http://ams.cstam.org.cn/EN/abstract/abstract157392.shtml