Physics informed neural networks for solving flow problems modeled by
the Shallow Water Equations
Abstract
This paper investigates the application of physics-informed neural
networks (PINNs) to solve free-surface flow problems governed by the
two-dimensional shallow water equations (SWEs). Two types of PINNs are
developed and analysed: a physics-informed fully connected neural
network (PIFCN) and a physics-informed convolutional neural network
(PICN). The PINNs eliminate the need for labelled data for training by
employing the SWEs, initial and boundary conditions as components of the
loss function to be minimized. Solutions obtained by both PINNs are
compared against those delivered by a finite volume (FV) solver for two
idealized problems admitting analytical solutions, and one real-world
flood event. The results of these tests show that the prediction
accuracy and computation time (i.e., training time) of both PINNs may be
less affected by the resolution of the domain discretization than the FV
model. Overall, the PICN shows a better trade-off between computational
speed and accuracy than the PIFCN. Also, our results for the two
idealized problems indicated that PICN and PIFCN can provide more
accurate predictions than the FV model, while the FV simulation with
coarse resolution (e.g., 5 m and 10 m) outperformed PICN and PIFCN in
terms of the speed-accuracy trade-off. Results from the real-world test
showed the finely resolved (10 m resolution) FV simulation generally
provided the most accurate approximations at flooding peaks. However,
both PINNs showed better speed-accuracy trade-off than the FV model in
terms of predicting the temporal distribution of water depth, while FV
models outperformed the PINNs in their predictions of discharge.