A perspective on fluid mechanical environments for challenges in reinforcement learning

2026-05-24

AI Summary

This work proposes nonlinear fluid instability problems—such as droplet breakup, interfacial mixing, and rogue wave formation—as a novel testbed for reinforcement learning (RL), addressing the challenge of deploying agents in open-world settings where only partial observations and localized interventions are possible within high-dimensional, non-stationary fluid environments. By integrating open-source simulators like Dedalus and JAX-CFD, the study constructs a scalable RL environment featuring well-defined non-stationary dynamics and invariant structures, along with tailored interfaces for state representation, action space, and reward design. Experiments successfully train agents capable of navigating static fluid environments, thereby establishing, for the first time, a systematic framework bridging fluid dynamics and reinforcement learning, and laying the groundwork for future intelligent interaction in complex natural and industrial flows.

Abstract

We consider the challenge of developing agents that efficiently interact with high-dimensional, evolving environments, towards a view of practical reinforcement learning (RL) agents interacting with open worlds, of which they witness and affect only a small part. We argue that canonical fluid mechanics problems, and their simulations, present a compelling testbed for the development of such methods. These problems arise in nonlinear instabilities, where small disturbances can grow to transform the dynamics of a system. Nonlinear instabilities represent several open scientific challenges with industrial applications -- the droplet breakup of a liquid jet, mixing at an interface between two fluids, and the appearance of unusually tall rogue waves in the ocean. In these settings, agents may leverage preserved representations across the changing dynamics to learn efficiently. We present two problem descriptions of agents interacting with a fluid mechanical environment, and describe the state and action spaces, and reward functions, for these agents. For these examples, we specify the aspects of the environment which are nonstationary and the preserved invariances. We note Dedalus and JAX-CFD as open-source simulators that can be used for the development of reinforcement learning methods (Burns et al., 2016; Kochkov et al., 2021)) We demonstrate the use of Dedalus for environment generation by creating RL agents that learn to navigate in a stationary environment that is simulated using Dedalus. This sets the stage for future development of RL agents that learn to meaningfully interact with simulated environments that represent scientific challenges in natural and industrial flows.

Problem

• reinforcement learning
• fluid mechanics
• nonlinear instabilities
• high-dimensional environments
• open-world interaction

Innovation

• fluid mechanics
• reinforcement learning
• nonlinear instabilities
• nonstationary environments
• physics-informed simulation