Abstract. Submersible aerial vehicle is capable of both flying in the air and submerging in the water. Advanced Research Project Agency (DARPA) outlined a challenging set of requirements for a submersible aircraft and solicited innovative research proposals on submersible aircraft since 2008. In this paper, a conceptual configuration design scheme of submersible unmanned aerial vehicle is proposed. This submersible UAV lands on the surface of water, then adjusts its own density to entry water. On the contrary, it emerges from water by adjusting its own density and then takes off from the surface of water. Wing of the UAV is whirling wing. It is set along aircraft's fuselage while submerging for lift reduction. We analysis aerodynamic and hydrodynamic performance of this UAV by CFD method, especially compare the hydrodynamic performance of the whirling wing configuration and normal configuration. It turns out that whirling wing is beneficial for submerging. This result proves that the configuration design scheme proposed in this paper is feasible and suitable for a submersible unmanned aerial vehicle.

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Hybrid corrugated sandwich (HCS) plates have become a promising candidate for novel thermal protection systems (TPS) due to their multi-functionality of load bearing and thermal protection. For hypersonic vehicles, the novel TPS that performs some structural functions is a potential method of saving weight, which is significant in reducing expensive design/manufacture cost. Considering the novel TPS exposed to severe thermal and aerodynamic environments, the mechanical stability of the HCS plates under fluid-structure-thermal coupling is crucial for preliminary design of the TPS. In this paper, an innovative layerwise finite element model of the HCS plates is presented, and coupled fluid-structure-thermal analysis is performed with a parameter study. The proposed method is validated to be accurate and efficient against commercial software simulation. Results have shown that the mechanical instability of the HCS plates can be induced by fluid-structure coupling and further accelerated by thermal effect. The influences of geometric parameters on thermal buckling and dynamic stability present opposite tendencies, indicating a tradeoff is required for the TPS design. The present analytical model and numerical results provide design guidance in the practical application of the novel TPS.