Edinburgh Wave Power Project: Fourth Year Report Volume 1 Of 3

Abstract

The results of measurements carried out at the National Maritime Institute, Feltham in February 1977 confirmed that scaling l aws operate well over the range from 1/150 to 1/15 and so we believe that it is safe to continue work in small tanks. We have tested ducks on a variety of mountings in the narrow tank over the entire range of sea conditions found at OWS India. The results p rovide sufficient input data for the full-scale power take-off design . We have developed techniques for generating very steep waves and have tested ducks in conditions likely to induce slamming. We are satisfied with duck behaviour in these conditions and do not regard slamming as our most serious problem. Photographs of the tests are contained in Volume 2 of this report. We have explored duck behaviour on mountings of variable compliance, and have discovered some striking effects. We find that there are two regions of efficient operation, one of which requires no restraint in heave . Ducks on mountings 1 with the right compliance can work better than those on fixed mountings and the right compliance can easily be achieved at full scale. Most of our effort has gone into making a wide tank with control of directional characteristics of random seas. Its design may prove of interest to other groups. It was ready for use in January 1978 and the cost e stimates proved accurate . Descriptions of the design and performance will be found in Volume 3 of this report. Results from our first month of experiments on free-floating backbones without ducks show that bending moments fall in the central sections of very long backbones and that static beam theory is difficult to apply. The full-time engineering strength of the team has risen to four with the arrival of Glenn Keller but I am sorry to report that we shall be losing two welcome visitors. Rick Jefferies, who has been working on non-linear problems for his Cambridge doctorate, will be going to CEGB, Marchwood. Ian Young is leaving us to r ead computer science here at Edinburgh. I would like to draw the attention of WESC to r eports by my colleague David Mccomb on polymer additions for hydraulic power transmission, by Graham Dixon on the anomalous heave force behaviour of horizontal cylinders and by Rick J efferies on theoretica l frequency and time domain models for ducks .