Study on the Motion Characteristics and Water Field Evolution of Cross-medium Aircrafts Entry Water in Tandem

The water entry in tandem of cross-medium aircrafts can improve the accuracy of striking near-surface targets. In order to obtain the flow field evolution law and motion characteristics when the cross-medium aircrafts entry water in tandem, a numerical simulation model of the cross-medium aircrafts entry water serially is established and compared with the experiment. The error is only 5.88%, which has high accuracy. Based on this, the water-entry characteristics of the cross-medium aircrafts with different distances and different initial speeds are studied. The trajectory, distribution of surface pressure, lift and drag coefficients of the cross-medium aircrafts are quantitatively analyzed, the vortex structure of the flow field and the evolution law of cavitation phenomenon are obtained. The results show that, under the condition of low speed and small spacing, the following aircraft enters the cavity of the first aircraft when it enters the water, which reduces the impact load of aircraft. Under the condition of low speed and large spacing, the following aircraft is affected by gravity, and the water-entry point moves backward, which cannot accurately enter the cavitation generated by the first aircraft, and the load-reduction effect is poor. Under the condition of high speed, the first aircraft produces large cavitation and complex vortex structure after entering the water, the attitude instability is obvious. The following aircraft moves in the cavitation of the first aircraft in tandem, the impact load of entering the water is greatly reduced, the flight attitude is relatively stable and the kinetic energy loss is small.