Turbulence measurements by sailplane

Abstract

Measurements of turbulence were made with a sailplane during a variety of meteorological situations. Data from a hot wire anemometer and an accelerometer were recorded on magnetic tape for subsequent analysis. The sailplane response, the hot wire and accelerometer characteristics, and the capability of the analysis gear permitted the spectrum of longitudinal turbulence to be measured over the wavelength range of 0.7 to 88 meters. The theoretical law relating the turbulent power spectrum to the −5/3 power of the wave number is consistent with the observed spectra. The data are not consistent with a spectrum slope magnitude as large as 1.85 or as small as 1.50. The vertical turbulence in the 40- to 60-meter wavelength range was found from the accelerometer data, and within broad limits of measurement accuracy the turbulence was found to be isotropic in this range.