Methodology to Evaluate Flutter on Geometric Nonlinear Structural Wings Applied to the Pazy Wing

Abstract

© 2024 by the American Institute of Aeronautics and Astronautics, Inc.This study investigates the nonlinear aeroelastic stability of the Pazy wing, a benchmark for theoretical aeroelastic research analysis within the Third Aeroelastic Prediction Workshop (AEPW 3 - NASA). Many institutions were challenged to predict the static deflections and flutter behavior in this case of a highly flexible wing subjected to structural geometric nonlinearity with flutter onset and offset along the wind-tunnel test. This paper presents the effort of the ITA-Embraer team in creating a methodology for matched flutter solution. The traditional flutter analysis is applied in a new nonlinear fluid-structure framework to explicitly account for solely the structural deflection with geometric nonlinearity. First the theoretical vibration modes are presented in comparison to test, which was within 3.5% difference. Then, the theoretical flutter speed are compared to experimental results, within 3.3% difference for onset and 2.8% difference for offset. When comparing theoretical undeformed condition to nonlinearly deformed condition there was 26 to 41% difference in flutter speed depending on the angle of attack. The results indicate that the matched solution approach is effective in capturing the flutter velocity with good accuracy being a simplified approach for capturing the main physics behind the problem.