A Method To Verify Longitudinal Stability Of3D WIG Models

The WIG is wing-in-ground effect ship which combines the advantages of ship and aircraft. Tosolve the problem of flight stability is very important and difficult in the design of WIG. Reserve safetyheight is not sufficient when WIG is flying over sea. So good automatic control system and longitudinalstability performance are the important guarantee of WIG’s security. Aerodynamic characteristics ofWIG change with height and angle of attack is radical nonlinear, and the flow field around is complex,so there is not enough statistical data and empirical formulas which is used to estimate the shape andaerodynamic performance parameters. This paper takes wings, tail, and fuselage into consideration tostudy longitudinal stability of WIG while sailing in ground effect zone.WIG’s stability design and testing mainly depend on wind tunnel testing and the model simulationtest with power. The test of WIG is high time consuming, because that there are three variables attackangle, flight height and velocity. Compared with the physical model test, numerical simulation islower-cost, and it has no restrictions on shape and size. The purpose of this paper is to analyzelongitudinal stability with numerical method and then help to design testing models of wind tunnelexperiment.The research includes numerical simulations of2D and3D models.In the2D numerical simulation, the paper has studied the aerodynamic characteristics ofNACA0012with and without wing-in-ground effect. Comparing the numerical data without groundeffect with experimental data, the validation of numerical simulation method has been verified, and usek-kl-omega turbulence model for subsequent calculations. The aerodynamic characteristics of the airfoilsection when affected by the ground effect with the change of attack angle, flight height and speed hasbeen studied.In the3D numerical simulation, WIG’s3D full size model has been studied. The process is asfollows. Firstly, a concept design of WIG has been accomplished. Establish model with Solidworks,generate mesh with Workbench and numerical calculate with Fluent. The calculation takes aerodynamicresponse of wings, tail and fuselage into account simultaneously. Finally, according to the results ofcalculation to judge whether the original design of concept WIG meet the requirements of thelongitudinal stability. If not, modify comments for further design should be putted forward.The paper summarizes the laws of the dynamic features of NACA0012wing section and that of the concept WIG model when affected by ground effect. And the defect of longitudinal stability has beenpointed.3D numerical simulation shows that the original concept WIG cannot meet the requirements ofthe longitudinal stability, when flight height is above1m. Obviously, it can’t adapt to the actual needs ofnavigation. Amendments are as follows, for further design the focus of attack angle should movebackward, by changing the aerodynamic layout, wing section, until it meets the stability requirements. Areliable numerical simulation approach for the design of WIG’s wind-tunnel model is provided.