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Title: FFM water mockup studies of the near-wake region of permeable flow blockages. [LMFBR]

Technical Report ·
DOI:https://doi.org/10.2172/7336048· OSTI ID:7336048

An experimental study of transport in the near-wake region of permeable, planar flow blockages was conducted in a vertical-flow channel with a hexagonal cross section. Experiments included measurements of axial pressure distributions along channel walls exposed to the free stream and wake region and pressure differences between the free stream and wake regions at fixed axial positions. Further, time constants for scalar decay in the near-wake region were determined by salt conductivity tests. A single blockage geometry was used in all tests; the blockage, which was attached to the channel wall, obstructed 58 percent of the cross section when the blockage was solid. For one series of tests, discrete jets were machined into the blockage and water was metered into the recirculation zone at velocities of the order of the mean channel velocity. Increased jet velocity reduced the resistence time of salt in the recirculation zone, and when the jet velocity was as high as the accelerated free stream flow at the vena contracta, counterrotating cells were introduced in the recirculating zone. In a second series of tests, uniformly spaced holes were drilled in the blockages to give blockage porosities of 11 and 24 percent. The residence time of salt in the near wake decreased significantly as the blockage porosity was increased to 24 percent.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
7336048
Report Number(s):
ORNL/TM-5514
Country of Publication:
United States
Language:
English