Question

which one of the following statements abou the energy equation ? 1. It is valid for both compressible and incompressible flow. 2. It is valid only if the flow is steady . 3. It is valid for viscous flow. 4. It is valid when shaft work is present.

Answer 1

The statement that is correct about the energy equation is that it is valid only if the flow is steady.

Step-by-step explanation:

Statement 2 is correct: The energy equation is valid only if the flow is steady.

Statements 1, 3, and 4 are incorrect:

1. The energy equation is not valid for both compressible and incompressible flow. It is valid for incompressible flow, but caution must be taken when applying it to compressible flow.
2. The energy equation is not valid for viscous flow. It is based on the assumption of frictionless flow.
3. The energy equation is valid, even when shaft work is not present. The equation describes the conservation of energy in fluid flow, regardless of whether shaft work is involved or not.