Coupled Reduced Order Models for Turbulent Flow
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Industrial applications, such as the simulation of flow around multiple interacting components, e.g. wind-farms, often present a challenge due to the size and complexity of the problem at hand. High-fidelity methods have become an indispensable tool in the solution of such problems and cannot be overlooked. However, the ever-increasing need for efficient simulators of large and/or parametrised systems proves infeasible for conventional techniques. The popularity of reduced order models (ROMs) has been rising due to their ability to efficiently approximate complex problems. Even then, there are challenges to the construction of a sufficiently parametrised ROM for such cases. This work explores the viability of the chain-ROM strategy in a turbulent scenario. We construct a singular hybrid ROM [1] component that would replace its high fidelity counterpart in a larger system, resulting in a nested chain-ROM strategy, where the output of a reduced components interfaces with the rest. The ROM component accepts highly parametrised perturbed, turbulent inflow conditions. Challenges include, among others, the sampling procedure, the complexity of the interface between ROM components, and the handling of time-dependent inputs. Moreover, the ROM itself combines data-driven and projection-based techniques, as well as corrective terms. Finally, the capabilities of the proposed strategy are tested by constructing a ROM component and emulating the turbulent flow over a series of simplified geometries and parametrised inflow conditions. [1] V. Tsiolakis, T. Kvamsdal, A. Rasheed, E. Fonn and H. van Brummelen, Reduced order models for finite-volume simulations of turbulent flow around wind-turbine blades. Journal of Physics: Conference Series, Volume 2018, 012042, 2021