@techreport{oai:jaxa.repo.nii.ac.jp:00045223,
 author = {小国, 保男 and 佐藤, 衛 and 神田, 宏 and 榊原, 盛三 and 三輪, 等 and OGUNI, Yasuo and SATO, Mamoru and KANDA, Hiroshi and SAKAKIBARA, Seizo and MIWA, Hitoshi},
 month = {Mar},
 note = {For years attempts have been made to improve the resolution of a colored Schlieren system used in the NAL 2D Hi-Re transonic wind tunnel. Experience have been ganined as to the relative advantages between the two colored Schlieren systems: the prism method and the color-filter method. The change of color is continuous for change of fluid density gradient with the former method while discontinuous with the latter. However, the latter method is less susceptible to disturbances due to density fluctuations in the plenum chamber through which the rays travel before being recorded, and is more appropriate when displaying qualitative pictures of the flow field. Firstly an attempt was made to cope with the plenum chamber noises by using a system with a cylindrical channel to isolate the ray paths from the disturbing plenum environment. Secondly to get better resolution for quantifying density gradients, a filter with a fine array of colors was successfully tried; the array consists of 47 stripes, each containing seven colors alternately from red to purple. The density gradients along the model surface were estimated from the Schlieren record, and were favorably compared with those obtained from the surface pressure distribution data. While it was observed that more improvement of the resolution is needed for accurate determination of the density field, the results so far show the merit of further exploring the procedure for deriving a density gradient field from two Schlieren records by using filters with the stripes of colors perpendicular to each other., 資料番号: NALTR0964000, レポート番号: NAL TR-964},
 title = {The Schlieren Observation System Installed in the NAL Two-Dimensional High-Reynolds Number Transonic Wind Turnnel and Attempts to Improve It},
 year = {1988}
}