The flow of a fluid becomes turbulent when
Correct answer: B. the speed exceeds a critical value and the Reynolds number becomes large
- A. the speed falls below a critical value
- B. the speed exceeds a critical value and the Reynolds number becomes large
- C. the pipe is perfectly smooth
- D. the fluid is very viscous
Explanation
Turbulence sets in when inertial effects dominate viscous ones, which is what a large Reynolds number expresses, and it appears as eddies and rapid mixing. A high viscosity favours laminar flow rather than turbulence, since it damps the disturbances out. Turbulent flow carries far more resistance, which matters in pipelines, aircraft design and blood vessels alike.
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About Fluid Flow
Fluid flow covers pressure, density, viscosity and the motion of liquids and gases through pipes or open channels. It includes the continuity equation, Bernoulli equation, streamline and turbulent flow, and the effects of changing area, height and speed. Viscosity and ideal fluid assumptions must not be confused with pressure effects.
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