👉 The Charles-Fluid Theory, proposed by Lord Rayleigh in the late 19th century, describes the behavior of gases under various conditions, particularly focusing on fluid dynamics and the relationship between pressure, temperature, and volume. It introduces the concept of "fluid fluid" (CF), a hypothetical medium that combines the properties of gases and liquids, allowing for the transfer of momentum and energy without significant viscosity. This theory was a precursor to more modern fluid dynamics models, offering insights into how gases behave under different pressures and temperatures, and it laid the groundwork for understanding phenomena like supercritical fluids. The Charles-Fluid Theory is particularly useful in explaining the unique properties of supercritical fluids, which exhibit characteristics of both gases and liquids, such as high diffusivity and solvating power.
