Simulation And Response Characteristics Of Water-based Aircarft Planing In Waves

It is a necessary condition for the safe take-off and landing of the water-based aircarft to have a certain anti-wave capability in the planing stage.In order to meet the requirements of sea adaptability design and safe take-off and landing operations,it is necessary to study the wave palning motion response characteristics and stability of water-based aircarft under medium and high sea conditions.In this paper,the main body of the aircraft is deep v-shaped,with a complicated geometric shape of wave baffles and longitudinal fault steps.Aiming at its high-speed planing problem,a numerical simulation scheme of planing motion of water-based aircarft in waves is formed by RANS method.Further study on the response characteristics of water-based aircarft planing in waves and the stable planing boundary diagram,to provide theoretical guidance for ensuring that it can achieve the design goal of landing and takeoff sea conditions and improve the adaptive design of future water-based aircarft in terrible ocean environment.When the water-based aircarft is planing in waves,the hydrodynamic force and position acting on the hull constantly change,and the pitch and heave motion response fluctuate within a certain range.The response amplitude is the key factor that affects the stability of the longitudinal planing of the water-based aircarft,and the time average response value plays an important role in it's safety and comfort,also the crew's operation prediction.At the same time,the large vertical overload(acceleration amplitude)will cause the crew's physiological discomfort,severely limit their operational ability,and pose a serious threat to the aircraft's maneuverability and structural safety.Therefore,length and height of regular wave,planing speed and longitudinal position of center of gravity of water-based aircarft are taken as influencing factors in this paper,to study the effects of these factors on the response amplitude and time average value of pitch and heave,and vertical overload of the midship and stem.On this basis,three motion modes of non-jumping,regular jumping and non-jumping by using the typical operating conditions of water-based aircarft planing in regular waves.And the conditional distribution of the three motion modes of the water-based aircarft under different planing speeds are studied.Then the jump distribution diagram of the water-based aircarft is drawn to provide theoretical guidance to avoid the non-safe sea conditions effectively.By comparing and analyzing the amplitude change of motion response with wave height under different motion modes,the influence of jump on the amplitude of motion response is studied.In order to predict the motion response of water-based aircarft during planing in typical irregular wave sea conditions,the research work is further extended to PM spectral irregular wave.Firstly,numerical simulation and verification analysis are carried out for the irregular wave.And by studying the variation law of significant wave height and peak period of the simulated spectral with the simulation duration,and comparing with the target spectrum,the appropriate simulation duration of the water-based aircarft planing in the irregular wave was determined under the requirement of simulation accuracy.Based on this,the historical response and statistical characteristics of pitch and heave,acceleration of midship and stem are studied under different planing speeds in typical high sea conditions(four-stage sea conditions).And through real-time monitoring of the aircraft longitudinal planing posture and vertical hydrodynamic changes,the aircraft planing longitudinal stability under each operating condition was preliminarily anticipated.It shows that the seaplane has a large longitudinal jump movement phenomenon in the four-stage sea condition when it's planing at high speed,which poses a serious threat to the aircraft structure and crew safety.Therefore the four-stage and worse sea conditions should be avoided effectively in the process of takeoff and landing.