Why is Direct Numerical Simulation (DNS) often computationally prohibitive for fully turbulent flows?

Answer

The required resolution scales with the Reynolds number cubed.

Direct Numerical Simulation requires simulating every swirling eddy, meaning the computational effort scales very rapidly with the Reynolds number, making it prohibitively expensive for high Re turbulent flows.

Why is Direct Numerical Simulation (DNS) often computationally prohibitive for fully turbulent flows?
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