Analyses for the Second Aeroelastic Prediction Workshop Using the EZNSS Code

The paper presents analyses that were performed with the EZNSS flow solver for the second Aeroelastic Prediction Workshop. The reference test cases for the Aeroelastic Prediction Workshop are based on two wind-tunnel experiments of the Benchmark Supercritical Wing, including a flutter test and forced excitation tests. Three cases are addressed at different transonic flow conditions: two cases at lower Mach numbers of 0.7 and 0.74 and 3 and 0 deg angles of attack, respectively; and one more physically complex case at Mach 0.85 and a 5 deg angle of attack. The cases are analyzed with the EZNSS code, using several computational setups and turbulence models. The simulations are able to predict relatively accurately the flutter response and the response to prescribed motion at the lower Mach number. The higher-Mach-number case, which involves a strong shock, separated flow behind the shock, and some flow unsteadiness, is more challenging. In the static analysis, different turbulence models yield different upper-surface shock positions, and none of the models are able to capture accurately the pressure recovery behind the shock. However, the unsteady aerodynamic response to prescribed pitch motion is simulated with good correlation to the wind-tunnel data. The paper also presents flutter predictions based on unsteady aerodynamic reduced-order modeling, thus validating and assessing the efficiency of the reduced-order modeling and the flutter prediction methodology.