A fluid is said to be ideal inviscous and incompressible.Ideal fluidAn ideal fluid is a fluid that has several properties including the fact that it is: • Incompressible – the density is constant• Irrotational – the flow is smooth, no turbulence • Nonviscous – (Inviscid) fluid has no internal friction ( η = 0)Ideal fluid do not actually exist in nature, but sometimes used for fluid flow problems.