Computational simulation of a submersible unmanned aerial vehicle impacting with water

A submersible unmanned aerial vehicle (UAV) is proposed firstly, which is capable of operating in both air and water. One of the outstanding characteristics of the UAV is that the air-water transition imitates that of a gannet, i.e., plunge-diving. In this paper, the plunge-diving process of this UAV is simplified as a water-entry problem with a certain initial velocity, and the impact force is calculated by the method of the computational fluid dynamics (CFD). The Volume of Fluid is coupled with the 3-D Navier-Stokes equations to establish the model of the flow field, and the equations are solved in Fluent 6.3. The phase distribution and the pressure distribution during water-entry are presented and analyzed. Furthermore, the effects of the dropping height and the wing´s sweptback angle on the impact force are investigated and discussed.