Quantitative Assessment of Pressure Waves in Guns
Abstract
Combustion instability in conventional guns is often manifested by the presence of longitudinal pressure waves traveling between the breech face and base of the projectile. Such waves are of concern because of their causal connection with high chamber pressures and pressurization rates which may in turn lead to breechblows, projectile or fuze malfunctions, and ballistic variability. While design approaches which minimize pressure waves are routinely employed today, the problem remains of specifying acceptable pressure-wave levels. This study addresses the establishment of the basis for an improved procedure for assessment of pressure waves. Several techniques are described for detecting the true pressure-wave signal from its carrier by removing what is essentially the classical Lagrangian pressure gradient from the experimental pressure-difference-versus-time profile, formed by subtracting the pressure- versus-time signal recorded at the forward end of the chamber from that recorded at the breech. The most successful approach is shown to be a digital Fourier- analysis technique involving multiple bandpass filtering of the recorded pressure-difference-versus-time profile. The resulting pressure-wave signal is characterized by an initial amplitude which is believed to be a physically well- motivated measure of the level of pressure waves and which offers procedural advantages in terms of both measurement and statistical processing of data. Integration of this technique into existing safety-assessment procedures is outlined.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1981
- Accession Number
- ADA100965
Entities
People
- A. W. Horst
- F. R. Lynn
- J. N. Walbert
Organizations
- Ballistic Research Laboratory