Physics Informed Neural Networks for Free Shear Flows

Abstract: The transformative impact of machine learning, particularly Deep Learning (DL), on scientific and engineering domains is evident. In the context of computational fluid dynamics (CFD), Physics-Informed Neural Networks (PINNs) represent a significant innovation, enabling data-driven fluid simulations while incorporating physics-based laws described by partial differential equations (PDEs). While PINNs have demonstrated efficacy in various fluid flow scenarios, a noticeable gap exists in their application to simulate jet flows - an essential category in engineering. Jets, crucial for downburst outflow, ventilation, and heat transfer, lack comprehensive exploration through PINNs in existing literature. This study addresses this gap by focusing on the application of PINNs to simulate steady jet flows, specifically 2D planar turbulent jet flow scenarios. The novelty lies not only in adapting PINNs for simulating jet flows but also in overcoming challenges such as poor convergence during training, attributed to imbalances in loss terms. We propose a novel PINN architecture for Reynolds-Averaged Navier-Stokes (RANS) simulation of steady turbulent jet flows, without the need for turbulence models and simulation data. Additionally, an extended dynamic weighting strategy is introduced to enhance the balance of loss term contributions in the PINN, resulting in improved convergence and more accurate predictions.