POD-based reduced order model for flows induced by rigid bodies in forced rotation

• Published in: Journal of fluids and structures 2019-11, Vol.91, p.102593, Article 102593
• Main Authors: Falaize, Antoine, Liberge, Erwan, Hamdouni, Aziz
• Format: Article
• Language: English
• Subjects: Fluid mechanics; FSI; Interpolation; Mechanics; Physics; POD; ROM; Turbomachinery
• ISSN: 0889-9746; 1095-8622
• DOI: 10.1016/j.jfluidstructs.2019.02.009

This paper deals with the construction of reduced order models (ROMs) for the simulation of the interaction between a fluid and a rigid body with imposed rotation velocity. The approach is a follows. First, we derive a monolithic description of the fluid–structure interaction by extending the Navier–Stokes equations from the fluid domain to the solid domain (rotor) similarly to the fictitious-domain approach. Second, we build a ROM by a proper orthogonal decomposition (POD) of the resulting multi-phase flow. This method consists in (i) constructing an optimal albeit empirical spatial basis for a very small subspace of the solution space, and (ii) projecting the governing equations on this reduced basis. Third, we cope with the reconstruction of the high-dimensional velocity field needed to evaluate the imposed velocity constraint by a POD of the rigid body membership function. This provides a substantial computation time saving compared to existing approaches. Fourth, we use a novel approach to interpolate between available POD bases to build the proposed POD-ROM for a range of parameters values. The complete procedure is applied to a simple configuration and proves efficient in the reconstruction of the velocity in both the fluid domain and the solid domain, while substantially reducing the computational cost.