Nonlinear aerodynamics of airfoils at low Reynolds number and its prediction model
Taking the GA(W)-1 airfoil as the research object,the influence law and physical mechanism of the Reynolds number on the aerodynamic characteristics of the airfoil through numerical simulation were investigated.The results showed that the airfoil had strong nonlinear aerodynamic characteristics such as catastrophe and hysteresis under low Reynolds number conditions,and the size of the hysteresis loop gradually decreased and even disappeared with the increase of Reynolds number.The breakup of the separation bubble at the leading edge of the airfoil and the irreversibility of this process constituted the physical origins of the nonlinear aerodynamic characteristics.The nonlinear aerodynamic characteristics of the airfoil under different Reynolds numbers were in accordance with the topological features of the cusp catastrophic model.Therefore,based on the principle of topology invariance,a high-precision topology mapping method was developed to establish the mapping relationship between cusp catastrophic model and nonlinear characteristics of the airfoil,then the nonlinear aerodynamic characteristics of the airfoil at low Reynolds number were successfully predicted by the equilibrium surface of the cusp catastrophic model,and the model error was less than 5％.
airfoillow Reynolds numbernonlinear aerodynamicscusp catastrophic modelprediction model
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