NASA STTR 2003 Solicitation

SMALL BUSINESS CONCERN (SBC):		RESEARCH INSTITUTION (RI):
NAME:	Clear Science Corporation	NAME:	Duke University (Dept. Mech. Engr.)
ADDRESS:	663 Owego Hill Road	ADDRESS:	180 Hudson Hall Box 90300
CITY:	Harford	CITY:	Durham
STATE/ZIP:	NY  13784-0233	STATE/ZIP:	NC  27708-9902
PHONE:	(607) 844-9171	PHONE:	(919) 660-5321

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name,Email)
Henry A Carlson
hcarlson@htva.net
U.S. Citizen or Legal Resident: Yes

TECHNICAL ABSTRACT (LIMIT 200 WORDS)
Clear Science Corp. and Duke University propose to develop and demonstrate
new and efficient computational methods of modeling nonlinear aeroelastic systems. The methods will extend the scope of multi-disciplinary computational tools like NASA Dryden's STARS by augmenting linear eigenmode stability algorithms and coupled time-marching techniques. The objective is low-dimensional models that accurately reflect nonlinearity in both structure and fluid and that are efficient enough to permit full exploration of parameter space. In Phase I, our team has demonstrated the technical merit and feasibility of two types of model order reduction: proper orthogonal decomposition (POD) of the coupled-system variables and the method of harmonic balancing (HB). The HB and POD methods represent complementary and synergistic tracks toward meeting the objective of modeling fully nonlinear aeroelastic systems, providing the capability of efficiently analyzing important nonlinear aeroelastic behavior like limit cycle oscillations, hysteresis, higher harmonic and sub-harmonic resonances, jump resonances, entrainment, beating, and period doubling. The innovation offers the possibility of engineering software for predicting nonlinear aeroelastic behavior that is as accurate and efficient as the current methods of analyzing linear systems and linear behavior like flutter. In Phase II, we propose to integrate the POD and HB methods into a single package that facilitates engineering trade-studies early in the design process.

POTENTIAL NASA COMMERCIAL APPLICATIONS (LIMIT 100 WORDS)
The proposed innovation offers new computational tools for designing next-generation aircraft like the NASA/Air Force F/A-18-AAW. Concepts like the F-18-AAW (Active Aeroelastic Wing) raise significant new challenges for engineers, requiring accurate prediction of nonlinear system responses in the presence of rapidly changing flight conditions and wing configurations. Integrating new methods of modeling nonlinear dynamics with existing NASA software can keep computational analysis capabilities apace with experimental flight testing. Computational models that cover a wide range of conditions and system responses (linear and nonlinear) will have a significant impact on design costs by reducing the number of required certification flight tests in future air vehicles and currently deployed systems.

POTENTIAL NON-NASA COMMERCIAL APPLICATIONS (LIMIT 100 WORDS)
Nonlinear behavior in coupled fluid-structure systems is ubiquitous, and commercial interest in engineering software designed to analyze these systems is high. Examples of nonlinear interactions between a flexible structure and surrounding flow include aircraft wings in flight, blood flow through arteries, the response of bridges and tall buildings to winds, turbine and compressor blade vibrations, the aero-response of automobile bodies (generating cabin noise), and oscillations in heat exchangers. Corresponding markets for software tools include the aerospace contractor community and civil transport airframe manufacturers, gas turbine and HVAC manufacturers, the automotive industry, rotorcraft companies, medical equipment manufacturers, and weapon system designers.