SBIR-STTR Award

The proposed effort will focus on the development of the parameterized Navier-Stokes (NS) based ROM for the Dynamic Flight Simulation (DFS) framework. The F/A-18 Active Aeroelastic Wing (AAW) aircraft will be used as the test case to investigate and validate the proposed methods.The background flow solutions under various Mach number and angle-of-attack grid points are first obtained by the FUN3D NS solver, thereafter the generalized aerodynamic forces around such nonlinear background flow at various frequencies are obtained by ZULUS using the linearized Euler solver. The computed aerodynamic solutions related to rigid-body modes will be corrected by flight-test or wind-tunnel derived data using the Lagrange multiplier technique. The three methods of achieving the parameterized ROM will be evaluated and compared to one another and conclusions and recommendations will be drawn upon based on the results. The Phase I effort will pave the way for the final integration of ROMs into the DFS framework for flight simulation and prediction.;

Benefit:
The DFS system, once developed, can be utilized for a number of purposes, including control law development, maneuvering flight simulations, flutter simulations and testing, flight loads testing, and handling quality assessments.A uniformed aeroelastic Reduced Order Modeling (ROM) technique across various flight conditions serves as the key component of the DFS framework which can rapidly solve the flight dynamic equations of motion with flexible effects in real-time.This technology has the potential of providing more accurate dynamic flight simulations for better situational awareness, system understanding for aircraft systems under test as well as being a useful tool for training engineers and test pilots.

The technical objective of the Phase II project is to develop the production-ready Dynamic Flight Simulation (DFS) system using the F-15 Saudi as a testbed and validate it with the F-15 Saudi flight test data. The key element in the DFS system is the Reduced-Order-Model (ROM)-based aeroelastic solver with an embedded aerodynamic forces database that is generated by a steady Navier-Stokes solver and ZONA Unstructured Linearized Unsteady Solver (ZULUS), respectively. The aerodynamic forces database contains a set of aerodynamic ROMs represented by the rational function approximation matrices that are uniformly accurate within the wide range of flight parameter space in terms of angle of attack, side slip angle and Mach number. Because of the ROM-based aerodynamic database, the DFS system can achieve the real-time simulation capability and perform continuous flight dynamic simulations across the flight parameter space. The DFS system provides a virtual flight test capability that can be used for many purposes including control law testing, trajectory simulation, flight quality assessment, flight loads generation, and prediction of aeroelastic and aeroservoelastic stability boundaries as well as physical understanding of observed in-flight dynamic behavior. Once the DFS system is developed, it will be production ready for commercialization.