Research On Taxiing Motion And Take-off And Landing Characteristics Of Amphibious Aircraft In Waves

Affected by sea conditions,the risk factor of amphibious aircraft during take-off and landing on water is relatively high.In order to meet the requirements of aircraft wave resistance design and safe take-off and landing operations on water,it is important to study the impact of complex sea conditions on the motion response and stability of amphibious aircraft during take-off and landing.Significance.The research object in this paper has complex shape structures such as upper single wing,buoy,longitudinal broken step,deep V-shaped single hull,etc.The aircraft speed changes in a large range during take-off and landing in waves,and the aircraft at different stages has its own typical motion response characteristics.Based on the CFD method and the overlapping grid technology,this paper establishes a numerical simulation scheme for the taxiing take-off and landing process of amphibious aircraft in waves,and analyzes the influence of wave elements and speed changes on the motion response and stability of the amphibious aircraft during taxiing,take-off and landing.Affected by fluid viscosity and grid factors,the wave propagation process has obvious attenuation phenomenon.In this paper,by adjusting the appropriate free surface grid size and time discretization format,the numerical simulation of long-domain regular waves is guaranteed to have high accuracy.The grid verification analysis is carried out for the amphibious aircraft’s uniform taxiing motion and landing water conditions,including the prism layer y+ verification,the model grid verification and the aircraft landing verification,and the feasibility of the numerical simulation scheme for the take-off and landing process of the amphibious aircraft is analyzed.The first part of this paper studies the heave,the maximum pitch,the maximum double amplitude,and the maximum and peak average of vertical overload at the bow and midship of the fuselage during the rollout process by changing the regular wave wavelength,wave height,and the way of aircraft acceleration.value changes.The second part is the research on motion response and motion stability of amphibious aircraft during unpowered landing in waves.The independent variables are wavelength,wave height and initial landing speed of the aircraft.In addition,numerical simulations are carried out for some working conditions of the amphibious aircraft taxiing on the static surface,and its stability and motion response characteristics are analyzed.The research results show that the unstable motion phenomenon of amphibious aircraft occurs frequently during take-off and landing in high sea conditions.The heave,pitch motion response and fuselage stability of the amphibious aircraft are greatly affected by the wavelength and wave height factors,and are affected by the acceleration change mode of the aircraft and the initial impact of water.The regularity of the effect of speed is poor.