Define an ideal fluid. What properties and behaviour characterize an Ideal fluid?
The correct answer and explanation is:
Correct Answer:
An ideal fluid is a theoretical concept in fluid mechanics that refers to a fluid with the following characteristics:
- Incompressibility – Its density remains constant regardless of pressure or temperature.
- No viscosity – It has no internal resistance to flow (i.e., no friction).
- Irrotational flow – There is no turbulence or rotation in its flow.
- No thermal conductivity – It does not conduct heat.
- No shear stress – It cannot sustain tangential forces; pressure acts uniformly in all directions.
300 Words Explanation:
An ideal fluid is a simplified model used in physics and engineering to understand the behavior of fluids without the complexities introduced by real-world factors like viscosity and compressibility. While no real fluid perfectly matches the definition, ideal fluids are a useful concept for solving fluid dynamics problems and developing theories.
One key property of an ideal fluid is incompressibility, meaning its density does not change even under high pressure. This assumption simplifies many calculations because it removes the need to consider density variations.
Another defining feature is zero viscosity. Viscosity is the measure of a fluid’s resistance to deformation or shear stress. In real fluids like honey or water, viscosity plays a role in slowing down flow near surfaces and causing energy losses. In an ideal fluid, this internal friction is entirely absent, leading to smooth, unrestricted flow.
The flow of an ideal fluid is also assumed to be irrotational and steady, meaning the fluid particles do not rotate about their own axes and the flow parameters do not change over time.
Additionally, an ideal fluid cannot support shear stresses, which means it only experiences normal stress in the form of pressure. This simplifies how forces are calculated in fluid flow problems.
Though ideal fluids do not exist in reality, this concept allows scientists and engineers to derive foundational equations like Bernoulli’s Equation and the Continuity Equation, which remain useful even when approximating real fluid behavior.