Accession Number : ADA549033


Title :   A Novel Approach to Turbulence Stimulation for Ship-Model Testing


Descriptive Note : Trident Scholar Project rept. no. 390


Corporate Author : NAVAL ACADEMY ANNAPOLIS MD


Personal Author(s) : Murphy, Jason C


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a549033.pdf


Report Date : 11 May 2010


Pagination or Media Count : 88


Abstract : Ship-model testing is vital component of naval architecture, allowing testing and evaluation on a small scale. The goal of this project was to develop an approach for creating a boundary layer on a ship-model that more closely represents the actual boundary layer on the ship. Flow within a ship s boundary layer is turbulent for nearly the entire length of the ship. However, in the boundary layer on a model, the flow can range from completely laminar, to intermittently laminar or turbulent, or fully turbulent. In order for model tests to provide accurate predictions of ship drag and powering, the boundary layer of the ship and the model must be similar. Currently, the solution to creating similar boundary layers is empirically based and is guided largely by the individual naval architect s experience and intuition. This project used analytical predictions and experimental data to work towards developing a set of guidelines to provide a more rational approach to replicating a ship s boundary layer through the use of turbulence stimulation. During the course of this project, the primary focus was on factors that affect boundary layer flow and transition and how these factors can be used for determining the optimum location of turbulence stimulation. A series of tests was performed first on a flat plate and then on a 2-D model. The tests consisted of using hot film sensors to measure the time fraction of turbulent flow within the model s boundary layer. These data were then analyzed to determine the most effective means to create a turbulent model boundary layer. The results obtained were able to shed light on the issues of sizing and placement of turbulence stimulation devices and provide guidance for future research in the field.


Descriptors :   *SHIP MODELS , BOUNDARY LAYER , BOUNDARY LAYER FLOW , DETECTORS , MATHEMATICAL PREDICTION , MODEL TESTS , STIMULATION(GENERAL) , TRANSITIONS , TURBULENCE


Subject Categories : Marine Engineering


Distribution Statement : APPROVED FOR PUBLIC RELEASE