Accession Number : AD0013532


Title :   MEASUREMENT OF TIMED SPARK SHADOWGRAPHS OF SHOCK VELOCITIES IN THE SHOCK TUBE


Corporate Author : LEHIGH UNIV BETHLEHEM PA INST OF RESEARCH


Personal Author(s) : Hoover, Herbert L


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/013532.pdf


Report Date : 01 Jul 1953


Pagination or Media Count : 30


Abstract : A rectangular shock tube with glass walls was used, and shock p ropagation near the diaphragm was studied quantitatively by means of double- spark shadowgraphs. The apparatus and method of measurement are described. Four groups of position-time measurements were made for chamber pressures of 15, 30, 45, and 60 psig; channel pressures were atmospheric. The average velocity over 3 intervals was computed. While keeping the position of the first shock pictures the same, all velocities were altered in such a ratio as to bring to a common value all average velocities over the interval from the first shock picture to the detection station. By assuming the average velocity over an interval to be the velocity at the mid-point, data for a velocity-distance curve were obtained. Sources of systematic error in Mach number determinations may be in distance and time intervals and in sound velocity. The largest systematic error is associated with the temperature gradients existing in the glass-walled chamber. Results indicate that it is impossible to interpret these velocity loss measurements by spark shadowgraphs as merely extending the earlier measurements. The measurements by spark shadowgraphs indicated higher velocities nearer the diaphragm, but the ideal theoretical value was not attained by the time a reasonably plane shcok had formed.


Descriptors :   *SHOCK TUBES , *SPARK SHADOWGRAPH PHOTOGRAPHY , *SHOCK WAVES , DETECTION , THESES , GLASS , TEMPERATURE GRADIENTS , ERRORS , PRESSURE , WALLS , LOSSES , ACOUSTIC VELOCITY , CHANNELS , RATIOS , MEASUREMENT , VELOCITY , TIME INTERVALS


Subject Categories : Test Facilities, Equipment and Methods
      Fluid Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE