In this paper, we present two deep learning-based hybrid data-driven reduced-order models for prediction of unsteady fluid flows. These hybrid models rely on recurrent neural networks (RNNs) to evolve low-dimensional states of unsteady fluid flow. The first model projects the high-fidelity time series data from a finite element Navier–Stokes solver to a low-dimensional subspace via proper orthogonal decomposition (POD). The time-dependent coefficients in the POD subspace are propagated by the recurrent net (closed-loop encoder–decoder updates) and mapped to a high-dimensional state via the mean flow field and the POD basis vectors. This model is referred to as POD-RNN. The second model, referred to as the convolution recurrent autoencoder network (CRAN), employs convolutional neural networks (instead of POD) as layers of linear kernels with nonlinear activations, to extract low-dimensional features from flow field snapshots. The flattened features are advanced using a recurrent (closed-loop manner) net and up-sampled (transpose convoluted) gradually to high-dimensional snapshots. Two benchmark problems of the flow past a cylinder and the flow past side-by-side cylinders are selected as the unsteady flow problems to assess the efficacy of these models. For the problem of the flow past a single cylinder, the performance of both the models is satisfactory and the CRAN model is found to be overkill. However, the CRAN model completely outperforms the POD-RNN model for a more complicated problem of the flow past side-by-side cylinders involving the complex effects of vortex-to-vortex and gap flow interactions. Owing to the scalability of the CRAN model, we introduce an observer-corrector method for calculation of integrated pressure force coefficients on the fluid–solid boundary on a reference grid. This reference grid, typically a structured and uniform grid, is used to interpolate scattered high-dimensional field data as snapshot images. These input images are convenient in training the CRAN model, which motivates us to further explore the application of the CRAN-based models for prediction of fluid flows.
Skip Nav Destination
Article navigation
January 2021
Research Article|
January 04 2021
Assessment of unsteady flow predictions using hybrid deep learning based reduced-order models
Sandeep Reddy Bukka
;
Sandeep Reddy Bukka
a)
1
Technology Center for Offshore and Marine, Singapore (TCOMS)
, 118411, Singapore
a)Author to whom correspondence should be addressed: sandeeprb@tcoms.sg
Search for other works by this author on:
Rachit Gupta
;
Rachit Gupta
b)
2
Department of Mechanical Engineering, University of British Columbia
, Vancouver, British Columbia V6T 1Z4, Canada
Search for other works by this author on:
Allan Ross Magee;
Allan Ross Magee
c)
1
Technology Center for Offshore and Marine, Singapore (TCOMS)
, 118411, Singapore
Search for other works by this author on:
Rajeev Kumar Jaiman
Rajeev Kumar Jaiman
d)
2
Department of Mechanical Engineering, University of British Columbia
, Vancouver, British Columbia V6T 1Z4, Canada
Search for other works by this author on:
a)Author to whom correspondence should be addressed: sandeeprb@tcoms.sg
b)
Electronic mail: rachit.gupta@ubc.ca
c)
Electronic mail: allan_magee@tcoms.sg
d)
Electronic mail: rjaiman@mech.ubc.ca
Physics of Fluids 33, 013601 (2021)
Article history
Received:
September 23 2020
Accepted:
November 17 2020
Citation
Sandeep Reddy Bukka, Rachit Gupta, Allan Ross Magee, Rajeev Kumar Jaiman; Assessment of unsteady flow predictions using hybrid deep learning based reduced-order models. Physics of Fluids 1 January 2021; 33 (1): 013601. https://doi.org/10.1063/5.0030137
Download citation file:
Sign in
Don't already have an account? Register
Sign In
You could not be signed in. Please check your credentials and make sure you have an active account and try again.
Sign in via your Institution
Sign in via your InstitutionPay-Per-View Access
$40.00