Feasibility Study And Dynamic Characteristics Analysis Of Negative Buoyancy Underwater Rotorcraft

With the development of ocean resources,the underwater vehicle plays an increasingly important role in ocean observation and detection.Traditional underwater vehicles,such as autonomous underwater vehicle(AUV)and underwater glider(AUG),must be trimmed to near neutral buoyancy state,with low space utilization and limited load capacity.It is difficult to meet the needs of increasingly diversified task sensors.In this paper,a new underwater vehicle based on negative buoyancy design is proposed,and its theoretical research is carried out:1.A new underwater vehicle called underwater rotorcraft is proposed.According to the working principle of the rotorcraft,the similarity model of the rotor is designed and manufactured,and the water tunnel test method is used to verify the rotation characteristics of the rotor at low speed flow,and the force and torque generated by the rotor in all directions are calculated.2.Feasibility study on working principle of self-rotating rotorcraft.A scaled similar CFD simulation model of the self-rotating rotor is established,and the simulation results are compared with the water tunnel test results.The feasibility of the simulation of the rotor flow field structure by CFD method is verified.On this basis,the hydrodynamic characteristics of the redesigned full-size rotor are simulated,and the correctness of the working principle of the underwater rotor is verified,and its advanced performance is demonstrated.3.Considering the influence of the rotor speed,lift angle,horizontal rudder angle and rotor angle of attack on the motion state,a dynamic model of six degrees of freedom is established,and the force analysis is carried out.The hydrodynamic coefficients of underwater rotorcraft are calculated by water tunnel test,CFD simulation and empirical formula.4.Simulate and solve the dynamic model of underwater rotorcraft through Matlab software,and the dynamic characteristics of horizontal,vertical and three-dimensional space are analyzed respectively,which provides a useful reference for the design and optimization of underwater rotorcraft.