Discrete Time State-Space Aeroservoelastic Modeling using FUN3D

The overall technical objective of the Phase II effort is to make OVERFUN as a fully multi-functional aeroelastic software system that can establish either the discrete time state-space plant model or the frequency-domain aeroelastic equation of motion with three embedded unsteady aerodynamic sub-systems; due to the structural deformation, the control surface deflection and the discrete gust excitation, respectively. All three unsteady aerodynamic sub-systems can be obtained by applying the extended complex variable differentiation (CVD) technique to the complex version of FUN3D, referred to as FUN3D-CVD, to generate the numerically exact linearized unsteady aerodynamic forces. As a wrapper around the steady Navier-Stokes (N-S) solver of FUN3D for trim analysis with static aeroelastic effects as well as a wrapper around the complex unsteady N-S solver of FUN3D-CVD for generating the three unsteady aerodynamic sub-systems, OVERFUN can establish a very accurate time-domain plant model or frequency-domain aeroelastic equation of motion that can capture all essential flow physics on a statically deformed aeroelastic model. To showcase that the OVERFUN generated plant model can be directly adopted by the modern control law design schemes for control system design, a classical and a robust flutter suppression and gust load alleviation control systems will be generated for the Benchmark Active Controls Technology wing with trailing edge flap as input as well as with the upper spoiler as input. A twin-engine transport flutter model (TETFM) that was tested by the Boeing engineers in the Transonic Dynamics Tunnel (TDT) will be selected as the test case to demonstrate the accuracy of the OVERFUN predicted aeroelastic solution for complex configuration by the validation with the TDT measured flutter boundary of the TETFM. The outcome of the Phase II effort will be a production-ready OVERFUN software system for commercialization in Phase III. More »