A nudged hybrid analysis and modeling approach for realtime wake-vortex transport and decay prediction

• Published in: Computers & fluids 2021-05, Vol.221 (C), p.104895, Article 104895
• Main Authors: Ahmed, Shady E., Pawar, Suraj, San, Omer, Rasheed, Adil, Tabib, Mandar
• Format: Article
• Language: English
• Subjects: Aerodynamics; Boundary conditions; Closure modeling; Computational fluid dynamics; Data fusion; Decay rate; Digital twins; Fluid flow; Forecasting; Galerkin projection; Model order reduction; Nonlinear filtering; Nudging; Proper orthogonal decomposition; Real time; Reduced order models; Sparse reconstruction; Transport equations; Uncertainty; Vorticity; Wake vortex
• ISSN: 0045-7930; 1879-0747
• DOI: 10.1016/j.compfluid.2021.104895

•We introduce a machine learning nudging framework for reduced order models.•Our approach puts forth a realtime predictive tool for wake-vortex transport and decay systems.•We explore the effects of measurements noise and state estimate uncertainty on modeling performance.•We found that our method effectively handles different levels of temporal and spatial measurement sparsity. We put forth a long short-term memory (LSTM) nudging framework for the enhancement of reduced order models (ROMs) of fluid flows utilizing noisy measurements for air traffic improvements. Toward emerging applications of digital twins in aviation, the proposed approach allows for constructing a realtime predictive tool for wake-vortex transport and decay systems. We build on the fact that in realistic application, there are uncertainties in initial and boundary conditions, model parameters, as well as measurements. Moreover, conventional nonlinear ROMs based on Galerkin projection (GROMs) suffer from imperfection and solution instabilities, especially for advection-dominated flows with slow decay in the Kolmogorov n-width. In the presented LSTM nudging (LSTM-N) approach, we fuse forecasts from a combination of imperfect GROM and uncertain state estimates, with sparse Eulerian sensor measurements to provide more reliable predictions in a dynamical data assimilation framework. We illustrate our concept by solving the two-dimensional vorticity transport equation. We investigate the effects of measurements noise and state estimate uncertainty on the performance of the LSTM-N behavior. We also demonstrate that it can sufficiently handle different levels of temporal and spatial measurement sparsity, and offer a huge potential in developing next-generation digital twin technologies for aerospace applications.