The obstacle block as a device to measure turbulent skin friction in compressible flowThe obstacle block, developed as an alternative to the Preston tube for indirectly measuring skin friction on smooth surfaces in incompressible flows, is examined as a device for compressible flows as well. The block, which is congruent with a surface static pressure orifice, has a geometry which is easily specified and thus has a universal calibration. Data from two independent studies are used to establish such a calibration using 'wall' variables, valid for Mach numbers up to about 3. Various aspects concerning practical application of the device are examined, such as sensitivity to yaw and the minimum permissible axial spacing between blocks. Several examples showing the utility of the device are given.
Document ID
19820041129
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Elfstrom, G. M. (National Aeronautical Establishment High Speed Aero Laboratory, Ottawa, Canada)
Kostopoulos, C. (National Aeronautical Establishment Ottawa Ontario, Canada)
Peake, D. J. (NASA Ames Research Center Moffett Field, CA, United States)
Fisher, D. F. (NASA Flight Research Center Edwards, CA, United States)