I am measuring a 2D turbulent flow using a split film probe. This gives a time history of the velocity in the x and y directions. I have a few questions about obtaining energy spectra from these measurements that I am hoping someone can help me with. The energy spectrum of the turbulent flow is acquired by taking the fourier transform of the spatial correlation between the fluctuating components of the flow. This gives energy as a function of wave number (length scale).(adsbygoogle = window.adsbygoogle || []).push({});

My first question is: How does this compare to taking a PSD of the total instantaneous velocity (not the fluctuations)? Does a PSD of the instantaneous velocity provide the same information as the energy spectrum of the fluctuations? Can I still expect to see a slope of -5/3 in the inertial range?

Second question: In my experiment I am using a single probe at a fixed location. So I am not able to measure spatial correlations. So by taking the PSD I am actually getting the energy as function of frequency. So can I still expect to see a slope of -5/3 in the inertial range or do I have to invoke Taylor's hypothesis?

Thanks

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# Questions about turbulence spectra

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