A Study of Shock Waves Moving over a Perforated Wall
Abstract
This study investigated the possible effects upon a shock wave moving over a pair of perforated test plates which were open to the atmosphere in the top and bottom walls of a shook tube. The effects of interest to this study were the shock strength, defined as the pressure ratio across the shock, and the shock orientation, indicated by the normality or obliqueness of the wave to the direction of flow. The number and size of the holes for a given open area, the open area, the rate of flow in through the perforations prior to shock passage, and the strength of the incident shock wave were all varied to determine the effects of these parameters. The results of this investigation showed that the strength of the shock wave, after being disturbed, was affected by the time required to establish the flow of air out through the perforations by the high pressure air behind the shock; If the holes were small, or flow out was established with some difficulty, the reflected shock waves formed at the openings of the perforations were observed to retard the attenuation of, or even strengthen, the incident shock wave. This occurred during a time lag before expansion waves, generated by the loss of mass out through the perforations could weaken the shock. These observations, made with pressure measuring instruments, were verified by the Schlieren photography.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1960
- Accession Number
- AD0243481
Entities
People
- Robert M. Cameron
Organizations
- Air Force Institute of Technology