Computational Uncertainty: Achilles’ Heel of Simulation Based Aircraft Design (invited)

In today’s marketplace for military aircraft, technological superiority at affordable cost remains the overarching demand of the customer community. Traditional design practices, which rely on extensive experimental testing to generate data for configuration design and on developing physical prototypes to verify functional and operational characteristic, cannot effectively tackle this challenge. Simulation based design (SBD) promises to rectify the deficiencies of traditional design practices by combining the ever increasing power of computers with increasingly sophisticated modeling and simulation technologies. SBD aims at producing a virtual prototype which can faithfully represent the functional and operational characteristics of the real airplane to be built. High-fidelity physics based computational methods are the key enablers. They are expected to generate credible estimates of data to meet SBD needs. However our ability to assess the credibility of computational estimates is severely hampered by our inability to quantify the associated computational uncertainty. Examples of computational fluid dynamics (CFD) applications from recent aircraft design efforts are presented to substantiate this assertion. It is imperative that we find effective ways of quantifying and mitigating computational uncertainty. Then only can we realize the full potential benefits of SBD—and its promise of helping aircraft industry deliver technologically superior aircraft at affordable cost.