Air Entrainment in the Hull Boundary Layer
Abstract
An experimental investigation of air entrainment at the free surface of the turbulentboundary layer along the hull of naval combatant ships is proposed. The hull boundarylayer will be simulated in the laboratory as a temporally evolving boundary layer createdby a suddenly started surface-piercing flat wall that will move at full scale ship speeds(15 m/s). In this experiment, the boundary layer at each instant in time (t) after the start ofthe wall motion is equivalent to the boundary layer on the full-scale ship at a distance ofx = Ut from the ship stem, where U is the ship speed. The moving wall is created by oneside of a one-meter-wide stainless steel belt loop that is driven by two vertically orienteddrums that are separated horizontally by a distance of 7.5 m. By using this belt system,full scale turbulent Froude and Weber numbers, which are necessary to simulate the airentrainment, will be obtained in the laboratory and the boundary layer is isolated from theeffects of breaking bow waves, which are also known to entrain air. The free surfaceshape and motion will be measured with a cinematic laser induced fluorescencetechnique, the turbulent fluid motions will be measured with a cinematic stereo particleimage velocimetry system and the bubbles will be measured with a cinematic stereophotography technique.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 04, 2017
- Source ID
- N000141712081
Entities
People
- James S Duncan
Organizations
- Office of Naval Research
- United States Navy
- University of Maryland