Turbulence is an omnipresent phenomenon – and one of the great mysteries of physics.
Turbulence is an omnipresent phenomenon – and one of the great mysteries of physics. A research team from Oldenburg has now succeeded in generating realistic storm turbulence in the wind tunnel of the Center for Wind Energy Research (ForWind).
Strong storms often seem to leave behind random destruction: While the roof tiles of one house are blown away, the neighboring property may not be damaged at all. What causes these differences are wind gusts – or, as physicists say, local turbulence. It results from large-scale atmospheric flows, but up to now, it is impossible to predict it in great detail.
Experts from the University of Oldenburg and the Université de Lyon have now paved the way for studying small-scale turbulence: The team led by Oldenburg physicist Prof. Dr. Joachim Peinke succeeded in generating turbulent flows in a wind tunnel. The flows resembled those occurring in big gales. The team has found a way to literally cut a slice out of a storm, the researchers report in the journal Physical Review Letters. "Our experimental discovery makes our wind tunnel a model for a new generation of such facilities in which, for example, the effects of turbulence on wind turbines can be realistically investigated," says Peinke.
The most important parameter characterising the turbulence of a flow is the so-called Reynolds number: This physical quantity describes the ratio of kinetic energy to frictional forces in a medium. In simple terms, you can say: The greater the Reynolds number, the more turbulent the flow. One of the greatest mysteries of turbulence is its statistics: Extreme events such as strong, sudden wind gusts occur more frequently if you look at smaller scales.
Read more at University of Oldenburg
Image: The active grid in the wind tunnel can stir up air flows to generate realistic storm turbulence. (Credit: University of Oldenburg/Mohssen Assanimoghaddam)
