The bulk modulus of most materials is very high compared to usual pressures, resulting in insignificant compression of most materials. Solids usually are even more incompressible than liquids. Wiki the bulk modulus to get a feel for the forces involved.KingDaniel said:Hi,
I read that an ideal fluid needs to be frictionless and incompressible.
Please explain why, especially the incompressible part?Thanks
Incompressibility is important in ideal fluids because it allows for the fluid to maintain a constant density, which is necessary for accurately predicting and calculating fluid behavior. It also simplifies mathematical equations and makes them easier to solve.
Incompressibility means that the volume of the fluid remains constant, so any changes in pressure or velocity must result in corresponding changes in density. This leads to a direct relationship between pressure and velocity, known as Bernoulli's principle, which is essential for understanding and predicting fluid flow.
No, in reality, all fluids have some degree of compressibility. However, ideal fluids, which are often used in theoretical and mathematical models, are assumed to be completely incompressible for ease of calculation.
The speed of sound in a fluid is directly related to its compressibility. In an incompressible fluid, the speed of sound is infinite, meaning that any changes in pressure or density will propagate instantly throughout the fluid. This is not the case in compressible fluids, where the speed of sound is finite.
Since ideal fluids are assumed to be completely incompressible, they cannot be compressed. If an ideal fluid experiences a change in pressure or density, it is no longer considered an ideal fluid and may exhibit different behaviors than predicted by ideal fluid theory.