Model Uncertainty: A Challenge in Nonlinear Coupled Multidisciplinary System Design

Abstract

This paper considers the e↵ects of uncertainty on multidisciplinary analysis estimates used in conceptual aircraft design. Specifically, the paper presents an analysis of the stability and control (S&C) characteristics of an illustrative Blended-Wing-Body (BWB) configuration using uncertain aerodynamic estimates. The S&C properties of a BWB are highly nonlinear, and as such pose a challenge for low-fidelity analysis techniques. By propagating bounds on uncertain aerodynamic data them through the analysis, bounds are derived for the resulting S&C limits. These estimates can then be used to guide future research and development e↵orts. Results demonstrate that even moderate uncertainty in estimating aerodynamic lift, drag, and moment coe cients translates into large uncertainty in estimating the center of gravity limits, due to the highly nonlinear nature of the S&C model. The paper identifies directions for ongoing work using a multifidelity approach to address this issue.

Effects of Aft-Body Extension Design on the Fundamental Characteristics of HWB Civil Aircraft

“…With the growing market requirements for fuel economy, noise, and emissions of civil aircraft, the research of novel configurations for civil aviation, such as Blended Wing Body [1][2][3][4][5][6][7], Double Bubble, Truss Braced Wing, Hybrid Wing body [8], Box Wing [9,10], etc., have become the focus of the industry. Among them, the HWB is an aircraft concept that adopts the integration of the fuselage and wing [11][12][13][14]. This configuration can reduce the wet area of the aircraft, thereby reducing the aircraft drag and improving the operation economy.…”