POD-Based Model-Order Reduction for Discontinuous Parameters

Reduced-order models (ROMs) based on proper orthogonal decomposition (POD) are widely used in industry. Due to the rigid requirements on the input data, these methods struggle with discontinuous parameters, e.g., optional rear spoiler on a car. In order to also include these types of parameters, a new method is presented that splits the full-order model (FOM) domain with its discontinuous parameters into multiple ROM subdomains. The resulting subdomains then again comply with the ROM requirements, and the established and proven ROM methods can be applied. The steps involved in computing a ROM based on the proposed method, by setting up the subdomains, mapping the FOM data into the domains, as well as computing the ROMs on the domains, are shown in detail in this paper. The method is employed on two use cases. The academic one-dimensional use case focuses on how the steps involved are employed and analyzes the introduced errors. The second use case's FOM is based on the DrivAer body with an optional rear spoiler computed using computational fluid dynamics (CFD) and demonstrates the usage in an industrial environment.