👉 Phys fluid, also known as a fluid dynamic or continuum fluid, is a concept in physics that describes substances like liquids and gases that exhibit properties of both solid and fluid states. These materials can flow and deform continuously under the influence of external forces, but they maintain a continuous structure at the microscopic level. Unlike gases, which are composed of widely spaced particles, fluids have particles that are closely packed but can move past each other. This unique behavior allows fluids to fill the shape and volume of their container, making them essential for various natural phenomena and engineering applications, from the flow of water in rivers to the movement of air in the atmosphere.