The Electromagnetic Velocity Gage and Applications to the Measurement of Particle Velocity in PMMA
Abstract
The electromagnetic velocity (EMV) gage was used to investigate particle velocity vs time and peak particle velocity vs distance at several points in PMMA (polymethylmethacrylate) in the donor-gap arrangement of the NOL Large Scale Gap Test. The results obtained by the method agree favorably with previously measured peak particle velocities for gap distances from the HE-PMMA interface between 10 and 25 mm. At closer distances the particle velocity-time records are in good relative agreement with one dimensional hydrodynamic computations. The values of peak particle velocity found for distances less than 5 mm are not in agreement with the previous extrapolation to zero gap of the earlier data obtained for gaps > or = 10 mm. Consequently, a new tentative calibration for the close-in distance is presented. The study encountered a number of recording problems; noise in the records and poor system response. Steps taken to eliminate the noise and to improve the recording response are outlined. Also discussed are the theoretical behavior of the gage, factors influencing systems response, and comparison of real with predicted response. It was concluded that the EMV gage is a convenient and useful tool for measuring particle velocity vs time in non-conducting or weakly conducting media.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 20, 1970
- Accession Number
- AD0717346
Entities
People
- David J. Edwards
- John O. Erkman
- Sigmund J. Jacobs
Organizations
- Naval Ordnance Laboratory