Which of the statements about turbulence is false?

Question

We sometimes prefer turbulent boundary layers because they delay flow separation

Turbulence can be calculated exactly from, for instance, the Navier-Stokes equations

Turbulent boundary layers have more kinetic energy than laminar boundary layers

We can force turbulent transition using, for instance, changes in surface roughness

Answer 1

The false statement among those listed about turbulence is:

Turbulence can be calculated exactly from, for instance, the Navier-Stokes equations.

While the Navier-Stokes equations govern fluid motion, turbulence is a complex phenomenon that generally cannot be calculated exactly due to its chaotic and unpredictable nature. In practice, turbulence is often studied using numerical simulations, empirical models, or turbulence models (like the k-epsilon or k-omega models) rather than exact solutions.