국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	Pressure Fluctuation Measurements in the NAL 0.2-m Supersonic Wind Tunnel
저자	Hideo Sawada, Takashi Kohno, Tetsuya Kunimasu
Keyword	quiet wind tunnel; supersonic wind tunnel noise
URL	http://send.nal.go.jp/send/jpn/dlpdf.php3/naltr0001355.pdf?id=NALTR0001355
보고서번호	NAL TR-1355
발행년도	1998.8
출처	NAL (National Aerospace Laboratory of Japan)
ABSTRACT	The two results obtained are almost the same mutually. The ratio of the rms value of the fluctuations to the total pressure of 75kPa remains under 0.1% at all tested Mach numbers from 1.5 to 2.5. It is possible to utilize an axial flow compressor for the quiet wind tunnel. Mach number and flow angle distributions along central 0.12 m long vertical line passing through the test section center were measured with a static pressure tube and a yaw meter. The change of largest 0.05 in Mach number and the change of largest about 1.0 degree in flow angle are observed. The comparison between the measured and numerical results at Mach number 2.0 suggests that the boundary layer on the nozzle plate maintains a laminar flow. The measured rms values of the pitot pressure fluctuations at the test section center show the values more than 0.1% of the Pitot pressure. The rms value becomes larger as the Mach number increases. The increment of the rms value suggests that some phenomenon of increasing the fluctuations like the eddy Mach wave radiation has originated during the flow passing the nozzle. Because the power spectrum density curve remains its shape between the settling chamber and the test section if the phenomenon increasing the pressure fluctuation does not exist, the rms value of the pressure fluctuation at the settling chamber must be less than 0.1% of the total pressure unlike 0.2% in order to make the rms value less than 0.1% at the test section.