An ideal fluid is a theoretical fluid that has no viscosity, surface tension, or compressibility. In other words, an ideal fluid flows without any resistance, has no surface tension, and its volume does not change with pressure. Real fluids, on the other hand, have all of these properties.

The main difference between an ideal fluid and a real fluid is that an ideal fluid does not experience shear stress, while a real fluid does. Shear stress is a force that acts parallel to the surface of a fluid. It is caused by the friction between adjacent layers of fluid. Real fluids experience shear stress because they have viscosity. Viscosity is a measure of how much resistance a fluid has to flow. The higher the viscosity, the more resistance the fluid has to flow.

Another difference between an ideal fluid and a real fluid is that an ideal fluid is incompressible, while a real fluid is compressible. Compressibility is a measure of how much a fluid can be compressed. The more compressible a fluid is, the more its volume can change with pressure. Real fluids are compressible because they have a finite volume. The volume of a real fluid can change with pressure because the molecules in the fluid can be squeezed closer together or farther apart.

Ideal fluids are often used in theoretical models because they are simpler to work with than real fluids. However, real fluids are more common in nature.

Here is a table that summarizes the differences between ideal fluids and real fluids:

I hope this helps! Let me know if you have any other questions.