Currently, the speed at which materials can be transferred between ships at sea is limited by sea conditions. Rough sea conditions cause the payload to swing making load transfer difficult and timeconsuming. The objective of this research is to develop a real-time, command compensating control for reducing sea state induced payload swing for shipboard robotic cranes. The future use of this cont...

Nonsorted circles are relatively barren patterned-ground features common in most arctic tundra regions. We studied how vegetation changes on nonsorted circles might affect cryogenic processes, which is of relevance as arctic vegetation responds to climate change. Twenty-eight circles at a moist nonacidic tundra site in northern Alaska received one of four treatments: (a) vegetation removal; (b)...

Three-dimensional tank in smooth tank is of concern in various engineering applications. Sloshing waves in moving tanks have been studied numerically, theoretically and experimentally in past several decades and many significant phenomena have been considered in those studies, especially the linear and nonlinear effects of sloshing wave with inviscid or viscid liquid in a tank. The reported stu...

Computational Fluid Dynamics is used to investigate the global forces and moments acting on the KVLCC2 hull form under going straight line, drift and pure sway planar motion mechanism tests. Simulated results are compared with experimental results for the unappended hull in shallow water and a fully appended hull with a propeller acting at the ship self propulsion point. A body fitted mesh unde...

Two models for ship roll motion and capsizing under stochastic excitation are analyzed using Melnikov’s method and control set analysis. The predictions given by these two methods are compared.

Unlike a transonic flow in compressible aerodynamics, a ship cruising steadily in a channel at nearly the linearized long wave speed generates unsteady wave motion. In a channel of limited width, solitons are radiated periodically up-stream. Such waves may have been the cause of a fatal accident at the Port of Harwich, England, and were described by a witness “like the white cliffs of Dover”. A...

This paper presents a recent numerical study conducted by researchers at the National Renewable Energy Laboratory on a point absorber wave energy conversion (WEC) system using a Reynolds-averaged Navier–Stokes (RANS)-based Computational Fluid Dynamics (CFD) method. The device we studied was a two-body floating-point absorber (FPA) that operates predominantly in heave and generates energy from t...

Abstract: This paper proposes a nonlinear backstepping control strategy to improve the inherent tradeoff between ride comfort of passengers and suspension travel. Passenger comfort in ground vehicles usually depends on a combination of vertical motion (heave) and angular motion (pitch and roll). Suspension travel means the space variation between vehicle body and tires. Our active suspension de...

This paper proposes a method to determine the flutter derivatives of 2-dimensional streamlined cylinders by means of a modified indicial approach adapted to a Navier-Stokes solver using an Arbitrary Lagrangian Eulerian formulation. The method relies on heave or pitch motion imposed to the section according to smoothed ramp time histories and on the computational evaluation of the transient forc...