Magnetic microparticles suspended on the liquid-air interface and subjected to an alternating magnetic field exhibit spontaneous formation of dynamic localized snake patterns. These patterns are accompanied by four large-scale hydrodynamic vortices located at the opposite ends of the snake patterns. We report detailed studies of these large-scale vortices and their relationship to the collectiv...

In the procedure of designing an underwater vehicle or robot, its maneuverability and controllability must be simulated and tested, before the product is finalized for manufacturing. Since the hydrodynamic forces and moments highly affect the dynamic and maneuverability of the system, they must be estimated with a reasonable accuracy. In this study, hydrodynamic coefficients of an autonomous un...

A non-linear model-aided PD approach for implementing heading control algorithms in the 6000 m depth rated Remotely Operated Vehicle (ROSUB 6000) has been developed by National Institute of Ocean Technology, India is presented in this paper. ROSUB 6000 is developed for carrying out gas hydrate surveys, poly-metallic nodule exploration, deep water interventions, bathymetric surveys and salvage o...

In this paper a three-dimensional mathematical model to simulate the hydrodynamic behavior of a tethered underwater robot system is proposed. The fluid motion around the robot is governed by mass and momentum conservation equations (Navier-Stokes equations). These highly nonlinear differential equations are solved numerically with the CFD code Fluent. From the numerical solution we obtain the h...

We study collisions between two strongly interacting atomic Fermi gas clouds. We observe exotic nonlinear hydrodynamic behavior, distinguished by the formation of a very sharp and stable density peak as the clouds collide and subsequent evolution into a boxlike shape. We model the nonlinear dynamics of these collisions by using quasi-1D hydrodynamic equations. Our simulations of the time-depend...

in this paper, combustion of char in the riser of circulating fluidized bed was modeled using aspen plus. since physical and chemical phenomena are involved in the process, the model integrates the two-phase hydrodynamic sub-model with the reaction sub-model derived from the literature. in the proposed model, the fluidized bed is divided into several sections and the behavior of each section wa...

This paper presents a simplified, tutorial approach to determining the gains of inertial confinement fusion ~ICF! targets, via a basic, zero-dimensional ~‘‘0-D’’!, energy ‘‘bookkeeping’’ of input ~parametrized by ICF drivers’ coupling efficiencies to the target, and subsequent hydrodynamic efficiencies of implosion! versus output ~thermonuclear burn efficiency and target fuel mass!. Physics iss...

Ellipsoidal micron-sized colloidal particles can oscillate spontaneously when trapped in a focused laser beam. If two oscillating particles are held in proximity their oscillations synchronize through hydrodynamic interactions. The degree of synchronization depends on the distance between the oscillators and on their orientation. Due to the anisotropic nature of hydrodynamic coupling the synchr...

In this paper we develop hydrodynamic models using spectral differential operators to investigate the spatial stability of swirling fluid systems. Including viscosity as a valid parameter of the fluid, the hydrodynamic model is derived using a nodal Lagrangean basis and the polynomial eigenvalue problem describing the viscous spatial stability is reduced to a generalized eigenvalue problem usin...

A simple upwind discretization of the highly coupled non-linear differential equations which define the hydrodynamic model for semiconductors is given in full detail. The hydrodynamic model is able to describe inertia effects which play an increasing role in different fields of optoand microelectronics. A silicon n −n−n-structure is simulated, using the energy-balance model and the full hydrody...