We report the development of a new methodology for analyzing CYLEX tests streak images. In these tests, the displacement of the wall of an explosive filled cylinder is obtained by backlighting the cylinder. The profile is imaged through a slit and streaked across a film record as the cylinder is detonated. A critical step in processing this data is the spatial calibration of the film and extraction of the profile of the cylinder from the image. Historically this has been a tedious task as it was performed by eye with the assistance of an optical comparator. Recently we developed an algorithm which automates the data calibration and extraction process of digitized streak records utilizing the Shen‐Castan edge detection algorithm and the image processing capabilities found in the IGOR PRO software. The new processing methodology greatly increases the resolution of the data, removes human subjectivity, and reduces analysis time from hours to seconds. The higher resolution of the new method has enabled much greater accuracy in measuring early‐time (<15 µs) expansion. With the aid of CTH hydrocode calculations, new fitting functions were developed to model both the early and late‐time expansion data. These functions contain physically meaningful fitting parameters and include terms which mimic the intensity and time scales of the shock and gas induced expansion of the cylinder independently. We demonstrate the methodology and hydrocode calculations on a recent CYLEX test series aimed at examining the effects of a plastic liner on high‐purity oxygen‐free copper cylinders filled with a high explosive.

No abstract

No abstract

This paper describes measurement methodology and comparative results obtained using both the Pressure Sensitive Paint (PSP) and novel Surface Stress Sensitive Film (S3F) techniques. A wind tunnel test was performed by EADS together with ISSI to investigate PSP at low speeds in order to compare absolute PSP pressures and S3F relative pressure data on a typical high speed aircraft model. Furthermore the ability of the S3F film to sense wall shear stresses was demonstrated.Measurements were conducted in the flow range of 10-50 m/s, angles of attack of 100 and 300 and with two model configurations (with and without an air brake).

The illumination of PSP-coated surfaces on a wind tunnel model by electro-luminescent surface layers has been tested in the laboratory as well as in the wind tunnel. All pressure data gathered by using this illumination technique was analyzed and compared with pressure results from tests using external illumination. The results are presented and discussed. The described illumination technique seems promising and could be adapted for model components in the future probably even in the presence of complex model structures.