Accession Number : AD0457278


Title :   TERMINAL VELOCITIES OF WINDOW DIPOLES USED IN HIGH ALTITUDE WIND MEASUREMENTS


Corporate Author : ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH (UNITED KINGDOM)


Personal Author(s) : Dawson, T W


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/457278.pdf


Report Date : Nov 1964


Pagination or Media Count : 27


Abstract : Various theoretical formulae for the rate-offall of window dipoles at altitudes up to 100 Km are shown to be in close agreement with the best available experimental data. At low altitudes velocity is determined mainly by conventional aerodynamic drag. At approximately 20 Km, Lamb's theory of viscous flow is required whilst at 50-70 Km, corrections must be applied for 'slip- flow'. Finally, above about 75 Km, 'free molecule flow' theory is needed to get good agreement with experiment. For the most accurate measurements of wind structure it is desirable to employ dipoles with the smallest possible terminal velocity. This means that the dipoles should have low density and the smallest possible thickness.


Descriptors :   *WIND , *FALLING BODIES , *FREE FALL MODELS , *RADAR CONFUSION REFLECTORS , VELOCITY , MEASUREMENT , HIGH ALTITUDE , RADAR EQUIPMENT , DRAG , UNITED KINGDOM , CORRECTIONS , LOW ALTITUDE , VISCOSITY , EQUATIONS , AERODYNAMIC DRAG , MATHEMATICAL ANALYSIS , THEORY


Subject Categories : Test Facilities, Equipment and Methods
      Electrical and Electronic Equipment


Distribution Statement : APPROVED FOR PUBLIC RELEASE