LiquidFun is a 2D physics engine designed for simulating fluid dynamics in real-time applications, particularly in games. It is an open-source project based on the principles of particle systems, allowing developers to create realistic water and other fluid effects with ease. The engine is built on top of Box2D, a popular physics engine, and provides a simple API for integrating fluid simulations into various platforms. LiquidFun supports features like buoyancy, surface tension, and collision detection, making it a versatile tool for game developers looking to enhance their projects with dynamic fluid behavior.