Aerodynamic Analysis Of WIG Craft Flying Over Wavy Ground Of High Grade Sea Conditions

WIG craft is defined as an aircraft heavier than air and fiying close tothe ground that use ground effect for the sake of better flight efficiency.The Wavy-Ground-Effect means that aerodynamic coefficients changeswith the wave form regularly when WIG craft flying over sea. The studyon Wavy-Ground-Effect have a direct impact on aerodynamic layoutdesign, stability analysis, and other factors to ensure flight safety, so it issignificant.Focusing on the deficiencies of exist research, the N-S equation ofunsteady incompressible flow and second order RNG k-ε turbulence modelwere solved in Fluent with the CFD simulation method to analyze the newquestions in Wavy-Ground-Effect in this article. Firstly, the necessity ofinvolving local wind speed and velocity of wave when researchingWavy-Ground-Effect numerically is investigated with2-dimensional cases.Besides, the trends and reasons that aerodynamic coefficients vary with ground clearances under Wavy-Ground-Effect are researched. We foundthat in Wavy-Ground-Effect of high grade sea condition, because of thedual role of the vortex and ground effect, the variation of drag coefficientdiffers from that in normal sea conditions, lift-drag ratio also changes withit, so the optimum cruising altitude of WIG craft under high grade seaconditions should be slightly higher than that in normal conditions.Secondly, we analyzed the aerodynamic force and the rolling moment of3-dimensional airfoil when the course angle between the direction of flightand local wind speed were different. The airfoil influenced by both localwind and ground effect, a rolling moment will appear on the WIG craft.The Rolling moment coefficient varies with the height of the wave surface,the lateral wind will Strengthen or weaken the Maximum and minimumvalue of rolling moment, so the rolling moment coefficient can’t be seen aschange in a sine curve. And then, The object of study is developed intothree-dimensional wing-body model of certain real seaplane, analyze theWavy-Ground-Effect of high grade sea condition with the model. Theresults of straight wing are verified to see if it is consistent with the resultsof the seaplane. Qualitative analysis of straight wing is developed intoquantitative analysis of seaplane to make the results more meaningful.This article provides a foundation for subsequent research on the impact of high grade conditions on WIG craft, it has an important value.