Fluid Dynamics MCQ with answer and solution

Concept

Forces considered in Euler's equation

Formula

dp/ρ + g dz + v dv = 0

Step-by-step solution

1. Euler's equation is derived from Newton's second law for an ideal fluid. 2. An ideal fluid has no viscosity and no turbulence. 3. Only gravity force and pressure force act on the fluid element.

Explanation

Euler's equation of motion assumes an inviscid fluid, so viscous and turbulent forces are neglected. Including viscous force gives the Navier–Stokes equations, and including viscous plus turbulent forces gives the Reynolds equation.

Shortcut

Euler = gravity + pressure. Navier–Stokes = + viscous. Reynolds = + turbulent.

Common mistake

Adding viscous force because real fluids are viscous.