Propeller induced structural vibration through the thrust bearing is an important source for low frequency shipboard noise and underwater sound radiation from a submarine hull. Such vibration is investigated using a scaled experimental model. This research concentrates on the experimental characterization of propeller force, hydrodynamic force of the thrust bearing and vibration transmission th...

The effect of electron spin-rotational (SR) interaction in species with an effective spin Seff= l/Z is treated for molecular rotations representing an adiabatic perturbation to the electronic system. Based on the adiabatic rotation of effective spin (ARES) concept as well as on the transformation of the Hamiltonian to the rotating molecular frame a useful expression is obtained for the effectiv...

Marine propellers display several forms of cavitation. Of these, propeller-tip vortex cavitation is one of the important factors in propeller design. The dynamic behaviour of the tip vortex is responsible for hull vibration and noise. Thus, cavitation in the vortices trailing from tips of propeller blades has been studied extensively. Under certain circumstances cavitating vortices have been ob...

In the last years, propeller flaps have become an appealing option for coverage of a large range of defects. Besides having a more reliable vascular pedicle than traditional flap, propeller flaps allow for great freedom in design and for wide mobilization that extend the possibility of reconstructing difficult wounds with local tissues and minimal donor-site morbidity. They also allow one-stage...

Diffusion-weighted (DW) imaging is widely used in clinical imaging. To address the strong distortion encountered in EPI-based DW techniques, split-blade DW-PROPELLER [1] was proposed. With PROPELLER, when imaging a small Field of View (FOV) of a large object, No-Phase-Wrap (NPW) is usually applied to remove aliased signal in each blade before combining them [2]. However, with this conventional ...

The similarity of rotation periods of, the anomalous X-ray pulsars (AXPs), the soft gamma ray repeaters (SGRs) and the dim isolated thermal neutron stars (DTNs) suggests a common mechanism with an asymptotic spindown phase, extending through the propeller and early accretion stages. The DTNs are interpreted as sources in the propeller stage. Their luminosities arise from frictional heating in t...

A series of wind tunnel experiments was conducted to study the e ect of propeller solidity and thrust axis inclination on the propeller normalforce coe cient. Experiments were conducted in the Langley 14by 22-Foot Subsonic Tunnel with a sting-mounted, counterrotation, scalemodel propeller and nacelle. Con gurations had two rows of blades with combinations of 4 and 8 blades per hub. The solidity...

Transient regimes arise when the propeller of a ship is operating in extreme seas, where ventilation and in-and-out of water effects results in loss of propeller thrust. By introducing Lyapunov based controller state reset, the performance in transient regimes may be increased without influencing the performance in calm seas. Improvements have been presented previously for dynamically positione...

This study investigated the effects of seawater on cavitation noise using a water jet test, a two-dimensional wing test, and a three-dimensional wing test. A model propeller cavitation test was conducted in a cavitation tunnel using seawater, in order to determine the effects of propeller cavitation more precisely. In the cavitation tests, measured propeller performance for both cavitation nois...

A technique integrating multishot periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) and parallel imaging is presented for diffusion echo-planar imaging (EPI) at high spatial resolution. The method combines the advantages of parallel imaging to achieve accelerated sampling along the phase-encoding direction, and PROPELLER acquisition to further decrease the...