Finnegan, the Massachusetts Institute of Technology Biomimetic Flapping Foil Autonomous Underwater Vehicle (BFFAUV), was developed to explore the use of two degree of freedom oscillating foils as the sole means of propulsion and maneuvering for an underwater vehicle. Two pairs of foils with 0.4m span x 0.1m chord are used, with one pair forward and one pair aft of the center of gravity, with th...

We investigate the feedbacks between surface processes and tectonics in an extensional setting by coupling a 2-D geodynamical model with a landscape evolution law. Focusing on the evolution of a single normal fault, we show that surface processes significantly enhance the amount of horizontal extension a fault can accommodate before being abandoned in favor of a new fault. In simulations with v...

In this paper, modeling and simulation of nonlinear, Half-car Active Vehicle Suspension System (HAVSS) reinforced with PID controller is presented. The model has 4 degrees of freedom; comprising of heave movements of the front and rear axle, pitch and heave motions of the unsprung mass of the vehicle. The vehicle is excited by a triangular bump on an otherwise smooth road. The objective of the ...

The sealing performance of end fittings is very important for offshore oil and gas pipelines. To investigate the sealing behavior of a ring-shaped wedge seal, global and local numerical models of the ring–pipe interaction have been developed based on the finite-element method. First, the sealing process of the ring under pressure is simulated. Second, a criterion for the penetration of fluid pr...

The genesis of some types of patterned ground, including hummocks, frost boils and sorted stone circles, has been attributed to differential frost heave (DFH). However, a theoretical model that adequately describes DFH has yet to be developed and validated. In this paper, we present a mathematical model for the initiation of DFH, and discuss how variations in physical (i.e. soil/vegetation prop...

The function diagram of active heave compensation hydraulic system has been given, besides, the mathematics model for the principal hydraulic components of the compensation system has been built, and the input-output relation between components has been made clear. Aimed at compensating work capacity for the system, design and research on parameters as the bearing pressure, the initial state an...

Longitudinal, heave and pitch, motion of ships in response to encountered waves can be smoothed using moving submerged wings, like transom flaps or a T-foil under the bow. Recently a 3 DOF detailed model of the surge, pitch and heave motions of a fast ferry has been developed, in terms of a structure of twelve transfer functions. On the basis of this model the most effective control for motion ...