CFD Based Investigation on the Hydroplaning Mechanism of a Cormorant’s Webbed Foot Propulsion

Jianhong Liang,Jinguo Huang,Xingbang Yang,Tianmiao Wang,Tim C Lueth

doi:10.1109/access.2020.2973356

Jianhong Liang, Jinguo Huang + Show 3 more

Open Access

https://doi.org/10.1109/access.2020.2973356

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Abstract

Aquatic unmanned aerial vehicles (AquaUAV) have aroused much attention from researchers, though no fully-featured aerial-aquatic UAV exists so far. The assistance of webbed foot hydroplaning can accomplish rapid take-off of a cormorant. A significant impact force and moment can be generated due to the webbed foot propulsion in the water-to-air transition. However, the change law of force and moment experienced by the cormorant during take-off has not been captured. Based on previous achievements in the biological investigation, we developed a biomimetic prototype with curve fitting model and parameter optimization to attain specific movements to imitate cormorant's hydroplaning strategy. The bionic webbed foot considers the elastic mechanics, and the forepart is regarded as flexible material for fluid-structure interaction (FSI). Dynamic process of rapid take-off in the aspects of flow characteristics and mechanical properties can be estimated by computational fluid dynamics (CFD) in our proposed FSI model, which establishes a foundation for further applications in the design of the assisted propulsion system of aerial-aquatic UAV.

Highlights

The aquatic unmanned aerial vehicle (AquaUAV) [1]) is a surging topic for both scientific and military missions [2]–[4]
GEOMETRIC MODEL Fig. 1 shows the modules and their respective data transfer associations required for this bidirectional fluid-structure interaction (FSI) process, which is the most complex form of FSI
Deformation, and displacement of the solid surface region are calculated after a certain time step, in which the displacement information will be transmitted to the fluid area

Summary

INTRODUCTION

The aquatic unmanned aerial vehicle (AquaUAV) [1]) is a surging topic for both scientific and military missions [2]–[4]. The flexible elastic deformation, inertia, soft body gravity, virtual limiter, the geometric motion of the linkage mechanism and fluid force are considered. The virtual limiter and the linkage are not provided with meshes, whose position information is only used for the solid mechanical calculation, and is not transmitted to the fluid area. In Fig. 3(E), We need to establish meshes only for solid part and flexible part, whose outer surface is used to transmit fluid force and displacement information. The main function of the solid part meshes are to provide the fluid calculation module with displacement information on the outer surface to obtain flow field variation near the solid part region. In the FSI, the force information and the displacement information are transmitted between two regions by interpolation. and the requirements of the fourth-order equation, the calculation consumption is quite large

MATHEMATIC MODEL

Findings

DISCUSSION