= Dan H. Neuhart
{c}
<Dan H. Neuhart> is the first named author, with <Catherine B. McGinley>, of the 2004 Langley study of <wind-tunnel turbulence intensity>. The report's title page identifies the byline and Langley affiliation. Its scientific contribution is an experimental characterization of tunnel flow with a specified signal chain, rather than an assertion that a facility has one universal turbulence number.<Free-Stream Turbulence Intensity in the Langley 14- by 22-Foot Subsonic Tunnel by Dan H. Neuhart and Catherine B. McGinley>[Title page, Summary and flow-quality survey]{ref}
The study combined <hot-wire anemometry>, velocity calibration and spectral analysis. The reported dynamic-data procedure retained approximately $1\,\mathrm{Hz}$ to $10\,\mathrm{kHz}$, sampled at $25.6\,\mathrm{kHz}$ and acquired simultaneous records. The distinction between sampling rate and retained bandwidth is essential: increasing the former does not establish which fluctuations were included in the reported intensity.<Free-Stream Turbulence Intensity in the Langley 14- by 22-Foot Subsonic Tunnel by Dan H. Neuhart and Catherine B. McGinley>[Printed p. 9, Dynamic Data Acquisition and Analysis]{ref}
An original ideal spectral example makes that distinction quantitative. Suppose a one-sided <power spectral density> is constant at $S_u=4\times10^{-8}\,(\mathrm{m/s})^2/\mathrm{Hz}$ across a selected $10000\,\mathrm{Hz}$ band and zero elsewhere. Then
$$
u_{\rm rms}^2=\int S_u(f)\,df=4\times10^{-4}\,(\mathrm{m/s})^2,
\qquad u_{\rm rms}=0.020\,\mathrm{m/s}.
$$
Keeping only a $1000\,\mathrm{Hz}$ subset of that flat band gives $u_{\rm rms}\simeq0.006325\,\mathrm{m/s}$. The changed answer reflects a changed integration band, not a measured improvement in the underlying flow. Real spectra are not generally flat; the invented example isolates the reporting issue without attributing either value to Neuhart's experiment.
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