We study the dynamics of a rigid card falling in air using direct numerical simulations of the two-dimensional Navier–Stokes equation and a fluid force model based on ordinary differential equations derived from recent experiments and simulations. The system depends on three non-dimensional parameters, i.e. the thickness-to-width ratio, the dimensionless moment of inertia, and the Reynolds numb...

Cerebral aneurysms are hypothesized to be acquired lesions resulting from a loss of static equilibrium in the apical region of the bifurcation, which causes the opening angle of the bifurcation to change during the cardiac cycle. Repeated dynamic cycling may disrupt wall elements in a manner analogous to a wire breaking with repeated bending and result in the formation of an aneurysm. A mathema...

The endwalls in a Taylor–Couette cell introduce adjacent boundary layers that interact with the centrifugal instability. We investigate the interaction between the endwall Ekman layers and the Taylor vortices near transition from nonvortical to vortical flow via direct numerical simulation using a spectral method. We consider a radius ratio of h50.75 in a short annulus having a length-to-gap ra...

background: the optimal strategy in percutaneous coronary intervention (pci) for coronary artery bifurcation lesions has yet to be agreed upon. we compared a strategy for stenting the main vessel to provide a complete perfusion flow in the side branch, namely thrombolysis in myocardial infarction (timi) - iii, with a strategy for intervention in both the main vessel and the side branch (mv + sb...

In this paper, the Bertrand's price competition in the retail duopoly with asymmetric costs is analyzed. Retailers sell substitute products in the framework of the classical economic order quantity (EOQ) model with linear demand function. The market potential and competitor price are considered to be the bifurcation parameters of retailers. Levels of the barriers to market penetration depending...

different discrete models of population dynamics of certain insects have been investigated under various feasible conditions within the framework of nonlinear dynamics. evolutionary phenomena are discussed through bifurcation analysis leading to chaos. some tools of nonlinear dynamics, such as lyapunov characteristic exponents (lce), lyapunov numbers, correlation dimension, etc. are calculated ...

Predicting the onset of shear band is significance in understanding failure geomaterials. The prediction accuracy dictated by constitutive model used for description pre-bifurcation behaviour. In this study, we first modify a recently proposed hypoplastic incorporating general strength criterion and stiffness function. We proceed to consider sand under true triaxial conditions. demonstrate that...

The rupture risk of unruptured intracranial aneurysms is known to be dependent on the size of the aneurysm. However, the association of morphological characteristics with ruptured aneurysms has not been established in a systematic and location specific manner for the most common aneurysm locations. We evaluated posterior communicating artery (PCoA) aneurysms for morphological parameters associa...

conclusions routine predilation of the sb in provisional stenting of true bifurcation lesions seems to be ineffective and might be associated with some undesirable consequences. still, there are some complex ostial lesions of the sb which could benefit from predilation. patients and methods sixty patients with true bifurcation lesions according to the medina classification were included in the ...