2. A substance that is able to flow freely; a liquid substance: "Please check the fluids in the car's engine."
3. A non-solid state of matter in which the atoms or molecules are free to move past each other; such as, in a gas or a liquid.
4. Used to describe something that can change easily or that changes often: "Boundaries between the farms were very fluid."
2. A class of liquid which stiffens into a semi-solid when subjected to a electric field.
Electrorheological fluids are commonly colloidal suspensions, and their stiffening under an electric field is reversible.
Under the electric field, electrorheological fluids form fibrous structures that are parallel to the applied field and can increase in viscosity by a factor of up to 105.
Lithium polymethacrylate is an example of an electrorheological fluid.
2. The experimental and mathematical-computational study of the mechanical behavior of fluids.
Fluid mechanics includes the transfer of heat and matter resulting from motion of the fluid, and the driving of the fluid motion due to differences in density which may be induced by temperature, as well as the effects due to temperature dependency of the constants of materials; for example, the viscosity.3. The study of fluids and gases at rest and in motion which can be divided into hydrostatics, the behavior of liquids at rest; hydrodynamics, the behavior of liquids in motion; and aerodynamics, the behavior of gases in motion.
Hydrostatics takes into account the forces exerted by a liquid in all directions, not just the downward gravitational pull; such as, the upward force exerted on a submerged object that causes bouyancy.
Hydrodynamics is the study of fluid flow and fluid friction, or viscosity.
Aerodynamics is the study of the motion of gases which is most often applied to the study of air and the motion of solid bodies in it.
The intuitive power of this model is expressed in common terms; such as, "flow" and "bottleneck", but the "fluid-flow analogy" is also used to construct sophisticated models of traffic behavior.
This includes hydrostatics, or the study of fluids at rest, and hydrodynamics or fluid dynamics, the study of fluids in motion.