Numerical Simulation Of Flowfield In A Helicopter Landing Process

As ship-borne helicopters play an increasingly important role in the ship’s combat system,its ability to safely and quickly take off and land determines whether the ship’s naval capability can be maximized.According to the theoretical and experimental analysis of previous researchers,the flowfield structure of the helicopter landing area will have a significant impact on its takeoff and landing process.However,in terms of numerical simulation,most of the previous discussions were carried out separately from the air wake field of a vessel and a rotor flowfield,and then by extracting a certain flowfield information into another flowfield for research,but ignoring the interaction between the two flowfields.This thesis comprehensively considers the characteristics of mutual interference between two flowfields,using FLUENT,ICEM and other commercial software as calculation tools to construct the ship/helicopter system model and numerical simulation of the coupled flowfield of the ship.And the following work has been completed.Firstly,the rotor flowfield is numerically simulated by the momentum source method,and the test data is compared to verify whether the method is suitable for simulating the rotor flowfield.Secondly,using a certain type of frigate as a model,the effects of ship surface structures,incoming wind direction and the inclination and sway of the ship during the navigation process on the air wake field of the ship are studied.Then,based on the study of the air wake field of the ship,combined with the momentum source method,a helicopter is used as a model to simulate the coupled flowfield near the landing region of the vessel,and compared with the simple superimposed flowfield,which further proves that the method is suitable for studying coupled flowfields.Thirdly,this thesis analyzes the changes of the flowfield during the helicopter landing on the ship and the changes of the aerodynamic forces of the helicopter,and studies the influence of the top obstruction of the hangar door on the aerodynamic forces of the rotor and the fuselage.Based on these,the best path for helicopter landing on the ship is pointed out according to the change of the wind direction.Finally,a numerical calculation model is established for the similarity criteria required for the wind tunnel test subsequently.Through the analysis of the calculation results,the similarity criteria suitable for the experimental study is obtained.Through the research in this thesis,the flowfield characteristics of the vessel’s air wake field can be effectively simulated by using k-ε model and hybrid grid,and further obtain the characteristics of flow structure and flow parameter distribution law of the coupled flowfield.Therefore,it is helpful to analyze the force of the helicopter landing process and to guide the way of landing.