Dynamic Aeroelastic Simulations of the Pazy Wing by UVLM with Nonlinear Viscous Corrections

Kurzfassung

The Pazy Wing test case is a benchmark for the investigation of aeroelastic effects at very large deflections. Tip deformations in the order of 50 % span were measured in wind tunnel tests which renders this model highly attractive for the validation of numerical aeroelastic methods and tools for geometrically nonlinear, large deflection analyses. Various wind tunnel tests close to regions of aeroelastic instability were performed recently by Technion, and limit cycle oscillations (LCOs) were observed at some of the test points. These LCOs are the result of structural and aerodynamic nonlinearities, especially flow separation. The simulation of such a complex and highly nonlinear phenomenon is the goal of our current activities within the Large Deflection Working Group of the 3rd Aeroelastic Prediction Workshop (AePW3). To restrict the modeling efforts and the computational complexity, the aerodynamic method (a potential-theory based UVLM) is extended to account for particular viscous effects, mainly flow separation. Therefore, the effective lift coefficient of each stripe of the vortex lattice grid is determined and the circulations of the panels of the stripe are modified once a maximum value is exceeded. The proposed method neglects dynamic effects but effectively limits the oscillation amplitude as is demonstrated by nonlinear time domain simulations in the unstable regime.