Abstract
In an on-going research project at SINTEF, ""Modelling the flow through fine-meshed pelagic trawls"", a theoretical basis for modelling, predicting and interpreting the flow in fine-meshed pelagic trawls has been developed. In order to verify the theoretical results, a series of tests with cones of fine-meshed netting has been carried out at the SINTEF flume tank in Hirtshals, Denmark. This report presents the materials, methods and results from these tests. A total of 8 combinations of taper ratio and solidity were tested. All cones had the same circular opening with a diameter of 0.8 [m] and taper angles from 4.5 to 15 degrees. Different types of woven synthetic monofilament fabrics with square mesh openings were used as cone material. Twine thickness and mesh openings of the fabrics were chosen so that the solidity ratio varied from 0.43 to 0.77. Mesh openings varied from 143 to 950 um. Measurement of drag and flow speed inside and outside the cones were made in nominal water speed of 0.15, 0.60 and 0.90 m/s. The flow speed was measured up-stream in front of the cone, inside and outside of the cone opening and in the centre of the cone at 3/4 cone length.
