Accession Number:

ADA346449

Title:

Development of Doppler Global Velocimeter (DGV)

Descriptive Note:

Final rept. 15 Aug 94-14 Nov 97

Corporate Author:

WEST VIRGINIA UNIV MORGANTOWN DEPT OF MECHANICAL AND AEROSPACE ENGINEERING

Personal Author(s):

Report Date:

1998-05-01

Pagination or Media Count:

38.0

Abstract:

A two component Doppler Global Velocimeter DGV and a two component Point Doppler Velocimeter PDV are described. Velocity measurements for both systems to quantify accuracy are presented. Results are presented for velocity distribution over the surface of a rotating wheel and fully developed turbulent pipe flow. Accuracy of PDV wheel velocity data is 1 of full scale, while linearity of a single channel is on the order of 0.5. Overall accuracy of wheel data matches cell calibration repeatability. PD pipe flow data show consistent turbulence intensities, and mean velocities agree with pitot probe data. However, a mean velocity offset error is observed. DGV system accuracy has also been investigated this system uses four 8 bit Hitachi CCD cameras, and a Matrox Genesis frame grabber board for image acquisition. For rotating wheel results, RMS noise levels are on the order of - 1 msec, while total velocity range errors are between - 1-2 msec. RMS noise is dominated by camera resolution. Pipe flow mean velocity measurements show reasonable agreement with centerline pitot probe data. The observed zero velocity offset has been corrected through use of a reference tab, to record zero velocity signals.

Subject Categories:

  • Electrooptical and Optoelectronic Devices
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE