👉 Classical fluid theory, also known as Newtonian fluid theory, describes a type of fluid behavior where the fluid's viscosity remains constant regardless of the applied shear stress or rate of deformation. This means that when a classical fluid is subjected to stress, it flows in a manner that is directly proportional to the applied force, following Newton's law of viscosity. The fluid particles move smoothly past each other without significant internal friction, and the fluid's behavior can be accurately predicted using simple mathematical equations. This theory is applicable to many everyday fluids like water, air, and most liquids, but it does not account for more complex behaviors seen in non-Newtonian fluids, such as those that change viscosity under varying conditions.
