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Title: Push-pull analysis of photonic Doppler velocimetry (PDV) measurements.

Abstract

Abstract not provided.

Authors:
;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1137298
Report Number(s):
SAND2007-1743J
Journal ID: ISSN 0034-6748; 523735
DOE Contract Number:
DE-AC04-94AL85000
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 78; Journal Issue: 7; Related Information: Proposed for publication in Review of Scientific Instruments.
Country of Publication:
United States
Language:
English

Citation Formats

Dolan, Daniel H., and Jones, Scott C. Push-pull analysis of photonic Doppler velocimetry (PDV) measurements.. United States: N. p., 2007. Web. doi:10.1063/1.2754405.
Dolan, Daniel H., & Jones, Scott C. Push-pull analysis of photonic Doppler velocimetry (PDV) measurements.. United States. doi:10.1063/1.2754405.
Dolan, Daniel H., and Jones, Scott C. Mon . "Push-pull analysis of photonic Doppler velocimetry (PDV) measurements.". United States. doi:10.1063/1.2754405.
@article{osti_1137298,
title = {Push-pull analysis of photonic Doppler velocimetry (PDV) measurements.},
author = {Dolan, Daniel H. and Jones, Scott C.},
abstractNote = {Abstract not provided.},
doi = {10.1063/1.2754405},
journal = {Review of Scientific Instruments},
number = 7,
volume = 78,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • A robust analysis method is presented for multiple-phase heterodyne velocimetry measurements. By combining information from three phase-shifted signals, it is possible to eliminate coherent intensity variations and incoherent light from the measurement. The three data signals are reduced to a pair of quadrature signals, allowing unambiguous calculation of target displacement. The analysis relies on a minimum number of adjustable parameters, and these parameters can be precisely determined from simple interferometer characterization.
  • Photonic Doppler velocimetry (PDV) has rapidly become a standard diagnostic for measuring velocities in dynamic compression research. While free surface velocity measurements are fairly straightforward, complications occur when PDV is used to measure a dynamically loaded sample through a window. Fresnel reflections can severely affect the velocity and time resolution of PDV measurements, especially for low-velocity transients. Shock experiments of quartz compressed between two sapphire plates demonstrate how optical window reflections cause ringing in the extracted PDV velocity profile. Velocity ringing is significantly reduced by using either a wedge window or an antireflective coating.
  • The short time Fourier transform (STFT) cannot resolve rapid velocity changes in most photonic Doppler velocimetry (PDV) data. A practical analysis method based on the continuous wavelet transform (CWT) was presented to overcome this difficulty. The adaptability of the wavelet family predicates that the continuous wavelet transform uses an adaptive time window to estimate the instantaneous frequency of signals. The local frequencies of signal are accurately determined by finding the ridge in the spectrogram of the CWT and then are converted to target velocity according to the Doppler effects. A performance comparison between the CWT and STFT is demonstrated bymore » a plate-impact experiment data. The results illustrate that the new method is automatic and adequate for analysis of PDV data.« less
  • We present detonation wave profiles measured in two TATB based explosives and two HMX based explosives. Profiles were measured at the interface of the explosive and a Lithium-Fluoride (LiF) window using 1550 nm Photon Doppler Velocimetry (PDV). Planar detonations were produced by impacting the explosive with a projectile launched in a gas-gun. The impact state was varied to produce varied distance to detonation, and therefore varied support of the Taylor wave following the Chapman-Jouget (CJ) or sonic state. Profiles from experiments with different support should be the same between the Von-Neumann (VN) spike and CJ state and different thereafter. Comparisonmore » of profiles with differing support, therefore, allows us to estimate reaction zone lengths. For the TATB based explosive, a reaction zone length of {approx} 3.9 mm, 500 ns was measured in EDC-35, and a reaction zone length of {approx} 6.3 mm, 800 ns was measured in PBX 9502 pre-cooled to -55 C. The respective VN spike state was 2.25 {+-} 0.05 km/s in EDC-35 and 2.4 {+-} 0.1 km/s in the cooled PBX 9502. We do not believe we have resolved either the VN spike state (> 2.6 km/s) nor the reaction zone length (<< 50 ns) in the HMX based explosives.« less
  • A planar Doppler velocimetry (PDV) system has been designed which is able to generate two beams from a single source separated in frequency by 690 MHz. This allows a common-path imaging head to be constructed, using a single imaging camera instead of the usual camera pair. Both illumination beams can be derived from a single laser and a set of acousto-optic modulators used to affect the frequency shifts. One illumination frequency lies on an absorption line of gaseous iodine, and the other in a region of zero absorption. The beams sequentially illuminate a plane within a seeded flow and Doppler-shiftedmore » scattered light passes through an iodine vapor cell onto the camera. The reference beam that lies in a zero absorption region is unaffected by passage through the cell, and provides a reference image. The signal beam, the frequency of which coincides with an absorption line, encodes the velocity information as a variation in transmission dependent upon the Doppler shift. Images of the flow under both illumination frequencies are formed on the same camera, ensuring registration of the reference and signal images. This removes a major problem of a two-camera imaging head, and cost efficiency is also improved by the simplification of the system. The dual illumination technique has been shown to operate successfully with a spinning disc as a test object and is currently achieving a velocity resolution of about +/-2 ms{sup -1}, limited by the quality of the light sheet generated from the multimode fiber. Automatic superposition of the signal and reference images is achieved, and polarization errors caused by the beam splitter in the conventional system are eliminated. Measurements have also been made on an axisymmetric air jet, seeded with a commercial smoke generator, which has maximum velocities of {approx}100 ms{sup -1}. A comparison with data obtained simultaneously, using a conventional two camera PDV arrangement has been made and the difference between the measurements found to be within a few m/s.« less