Turbulence wall-shear stress sensor for the atmospheric surface layer
نویسندگان
چکیده
A new sensor is described for measuring the fluctuating component of the wall-shear stress in the atmospheric surface layer over relatively smooth uniform terrain. The sensor was tested at the Surface Layer Turbulence and Environmental Science Test (SLTEST) site on the western salt flats of Utah, giving the first ever direct measurements of this quantity in an atmospheric-scale flow. The device consists of a lightweight floating element whose position is detected using a spherical mirror which deflects a laser beam onto a duo-lateral position-sensing photodiode. The sensor has a frequency response of 25 Hz and a circular sensing area of 50 mm diameter, making it suitable for atmospheric-scale measurements. Preliminary cross-correlation of wall-shear stress and velocity, from simultaneously sampled sonic anemometers, indicates structure-inclination angles that are consistent with analogous laboratory-scale turbulent boundary-layer measurements.
منابع مشابه
Reynolds number invariance of the structure inclination angle in wall turbulence.
Cross correlations of the fluctuating wall-shear stress and the streamwise velocity in the logarithmic region of turbulent boundary layers are reported over 3 orders of magnitude change in Reynolds number. These results are obtained using hot-film and hot-wire anemometry in a wind tunnel facility, and sonic anemometers and a purpose-built wall-shear stress sensor in the near-neutral atmospheric...
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