Phase A-2, Large Cavitation Channel, David Taylor Naval Ship Reasearch And Development Center

Abstract

The Large Cavitation Channel (LCC) has very tight performance specifications for the flow quality in the test section, both for uniformity of the mean velocity profiles and turbulence levels. The mean velocity profiles have been addressed experimentally in the Task A report, and mathematically in the Task B report. This task is concerned with the turbulence levels in the test section. Turbulence levels are partially controlled bY,honeycomb design. Model studies of honeycombs should be conducted at as high a Reynolds number as possible to reduce scale effects. Thus, the decision was made not to utilize the undistorted 1 to 10 scale model of the preliminary Kempf and Remmers (K&R) contraction, test section, and diffuser that was used in the Task A studies as the Reynolds number based on honeycomb parameters was judged to be too low to obtain meaningful results. The existing wind tunnnel facility was modified for the turbulence measurements in rather an unique manner so that full scale honeycombs could be evaluated. These modifications were made after the tests of the Task A program were completed. Results of the turbulence measurements and recommendations for a turbulence management system for the LCC are discussed in the following sections.