A Sensitivity Study of Bow Variants on the Distribution of Sea Spray in Regular Head Seas
Abstract
This thesis deals with improving a ship's operability by studying the effects of bow flare on the quantity and distribution of spray cross the main deck under varying environmental conditions. A 1:36 scaled model of a 3600 LTon displacement ship, resembling a U.S. Navy FFG-7 class combatant, was used throughout this study. The model was tested with 4 different bows with varying degrees of flare. A surfactant was added to the towing tank water to reduce surface tension and increase the Weber Number to better simulate spray at the model scale. Environmental conditions imposed were regular head seas of a mean sea state 6 and generated true wind equivalent to 32 knots. One bow form was first tested in ordinary tank water so that a comparison could be made between two surface tension conditions. A 64% reduction in surface tension was achieved through addition of the brand name surfactant AEROSOL OT-75. The visual effect on the spray was to cause a finer droplet size and break up of the water sheet that normally is present rolling off the bow. The reduction in surface tension resulted in: (a) a smaller volume of spray water being captured, (b) a change in density distribution of spray across the main deck, and (c) an increase in the wetted area on the main decking. The general trend was to reduce the quantity of spary water delivered and limit its distribution with an increase in the bow flare. The one knuckled bow that was tested performed much worst than any of the conventionally flared bows. (RWJ)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1990
- Accession Number
- ADA226655
Entities
People
- David T. Sapone
Organizations
- Massachusetts Institute of Technology