Critical richardson number

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critical Richardson number

The value of the gradient Richardson number below which air becomes dynamically unstable and turbulent.

This value is usually taken as Ric = 0.25, although suggestions in the literature range from 0.2 to 1.0. There is also some suggestion of hysteresis, where laminar air flow must drop below Ri = 0.25 to become turbulent, but turbulent flow can exist up to Ri = 1.0 before becoming laminar.

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