perfect fluid
Quick Summary
A perfect fluid, also known as an ideal fluid, is a theoretical concept in physics. It is defined as a fluid that cannot conduct heat and offers no internal resistance to flow. This means a perfect fluid has zero viscosity.1
In contrast, real fluids have viscosity, which is their resistance to flow. This resistance arises from friction between adjacent layers of the fluid as they move past each other. Viscosity can be thought of as the "thickness" of a fluid. Liquids and gases are both considered fluids because they deform continuously under shear stress.123
While real fluids always possess some degree of viscosity, some fluids with very low viscosity and heat conductivity can approximate the behavior of a perfect fluid.1
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