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Effects of hot-wire measurement in wall-bounded flows studied via direct numerical simulation

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The effect of limited spatial and temporal resolution for hot-wire anemometry is investigated using recent DNSes of a zeropressure-gradient turbulent boundary layer in the range of Reθ=4000-6500, and channels at comparable Reτ. Different spanwise filters are applied to the different velocity components to reproduce the effect of finite wire lengths. Results show that the streamwise turbulent energy at the buffer layer is severely attenuated, while the logarithmic and outer regions are less sensitive to the length of the wire. Attenuation of the streamwise energy seems to be Reynolds independent for the present range of Reynolds numbers, and spectral results are used to predict what the behavior will be beyond that range.

Author(s):

Juan A. Sillero    
Universidad Politecnica de Madrid
Spain

Javier Jimenez    
Universidad Politecnica de Madrid
Spain