This paper presents the unique failure characteristics, such as fragmentation, internal cracks, general deformation and pitting, observed on a SS420C ball bearing from direct blast loading using cylindrical PE-4 explosive. Axisymmetric simulations were performed to gain insights of mechanisms. While additional work is needed fully understand all characteristic found, valuable findings have been...

Although quasi-periodic oscillations (QPOs) have been discovered in different X-ray sources, their origin is still a matter of debate. Analytical studies of hydrodynamic accretion disks have shown three types of trapped global modes with properties that appear to agree with the observations. However, these studies take only linear effects into account and do not address the issues of mode excit...

We present an analysis of the primary bifurcations that occur in a mathematical model that uses the (three-dimensional) Navier-Stokes equations in the Boussinesq approximation to describe the flow of a near unity Prandtl number fluid (i.e. air) in the differentially heated rotating annulus. In particular, we investigate the double Hopf (Hopf-Hopf) bifurcations that occur along the axisymmetric ...

We present an efficient method for computing numerically the solution to the time-dependent Maxwell equations in an axisymmetric domain, with arbitrary (not necessarily axisymmetric) data. The method is an extension of those introduced in [20] for Poisson’s equation, and in [4] for Maxwell’s equations in the fully axisymmetric setting (i.e., when the data is also axisymmetric). It is based on a...

An analysis is presented of parametric instability in a finite-length rotating cylinder subject to periodic axial compression by small sinusoidal oscillations of one of its ends (the ‘piston’). The instability is due to resonant interactions between inertialwave (Kelvin) modes of the cylinder and the oscillatory compression and is resisted by viscosity, acting both through thin boundary layers ...

This paper presents a quasi-local method of studying the physics of dynamical black holes in numerical simulations. This is done within the dynamical horizon framework, which extends the earlier work on isolated horizons to time-dependent situations. In particular: (i) We locate various kinds of marginal surfaces and study their time evolution. An important ingredient is the calculation of the ...

SANDIP K. CHAKRABARTI, D. DEBNATH, P.S. PAL, A. NANDI, R. SARKAR, M.M. SAMANTA, P.J. WIITA, H. GHOSH and D. SOM S. N. Bose National Centre for Basic Sciences, JD-Block, Sector III, Salt Lake, Kolkata, 700 098, India. E-mail:[email protected] 2 Centre for Space Physics, Chalantika 43, Garia Station Rd., Kolkata 700084, India. 3 Department of Physics & Astronomy, Georgia State University, PO B...

Turbulent non-homogenous flow environments at high-energy tidal sites lead to variation in power performance of stream turbines. In addition, non-uniform loading due combined effects shear and elevated inflow turbulence affects device survivability. the current study, an active-grid generator is used mimic sheared-turbulent representative flood (low shear) ebb tides (high shear). The near-wake ...