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...

We report on the experimental studies of the deformation and fragmentation of liquid metal droplets by picosecond and subpicosecond laser pulses. The experiments were performed with laser irradiance varying in 10-10 W/cm range. The observed evolution of the droplet shape upon the impact dramatically differs from the previously reported for nanosecond laser pulses. Instead of flattening the drop...

This paper presents a numerical method for studying water impact of a two-dimensional body of arbitrary cross-section. The global simulation procedure based on the boundary element method is constructed. The attention is focused on the computational description of the jet flow in the framework of a potential flow assumption. The proposed computational model makes the numerical analysis more sta...

This study was motivated by the two-dimensional hydrodynamic slamming problem of a steep wave hitting a vertical wall. The fundamental problem considers dual impact on the wall at the lower and upper region resembling the impact of a wave at the time of its breaking. The solution method results into a mixedboundary value problem that involves a triplet of trigonometrical series which, to the au...

With the improvement of Smoothed Particle Hydrodynamic (SPH), it has become one of most vigorous methods for breaking wave simulation. Recently we have developed an improved SPH method for simulating violent flow and wave impact to different angle slopes. The main features of the new method include the incompressible SPH method based the incompressible Poisson equation, and it also gives a new ...

This paper presents a two-dimensional hydrodynamic simulation tool for studying the effectiveness of hypervelocity kinetic-energy impactors (KEIs) and nuclear subsurface explosions for disrupting (i.e., dispersively pulverizing) hazardous asteroids. High-order methods on GPUs (Graphics Processing Units) are employed for hydrodynamic simulations of such complex physical problems. Because highord...

BACKGROUND Proteinase activities are often measured using chromogenic substrates that are much smaller than physiological substrates. METHODS The hydrodynamic size of macromolecular substrates (macrosubstrates) prepared by linking small chromogenic substrates to polyethylene glycol was determined by gel filtration. Efficiency of macrosubstrate cleavage by proteinases and alpha(2)-macroglobuli...

The significance of the transport of nutrient-rich hypolimnetic water via the benthic boundary layer (BBL) to the productivity of Mono Lake was studied using a coupled hydrodynamic and ecological model validated against field data. The coupled model enabled us to differentiate between the role of biotic components and hydrodynamic forcing on the internal recycling of nutrients necessary to sust...

In this paper, we present the results of smoothed particle hydrodynamic (SPH) simulations of collisions between pre-main sequence stars and a variety of other kinds of stars. Simulations over a range of impact parameters and velocities were performed. We find that pre-main sequence stars tend to “wrap themselves” around their impactor. We discuss the probable evolutionary state of products of c...