The paper reviews striking features of swirling flows—collapse, swirl generation, vortex breakdown, hysteresis, and axisymmetry breaking—and the mechanisms involved with the help of conical similarity solutions of the Navier-Stokes equations. The strong accumulation of axial and angular momenta, observed in tornadoes and flows over delta wings, corresponds to collapse, i.e. the singularity deve...

This paper is concerned with the airway closure problem and investigates the quasi-steady deformation characteristics of strongly collapsed (buckled) airways occluded by liquid bridges of high surface tension. The airway wall is modeled as a thin-walled elastic shell, which deforms in response to an external pressure and to the compression due to the surface tension of the liquid bridge. The go...

Osteonecrotic collapse of the femoral head is a common refractory disease in orthopedics, and the occurrence of collapse is an important factor in the prognosis of this condition. Osteonecrotic collapse of the femoral head can be delayed or prevented by the formation of a sclerotic rim. This study used finite element analysis to evaluate the mechanical role of a proximal sclerotic rim on stress...

Dynamic conditions of the upper respiratory tract in the horse are being increasingly diagnosed across multiple disciplines with the improved diagnostic abilities in over ground endoscopy. Numerous conditions including palatal malfunction, pharyngeal wall collapse, vocal cord collapse, axial deviation of the aryepiglottic folds, intermittent epiglottic entrapment, and arytenoid dysfunction have...

Progressive collapse assessment of a reinforced concrete (RC) building designed only for gravity loads and lacking dedicated lateral load resisting system was carried out using the alternate path (ALP) method finite element (FEM) numerical model created in software SAP2000. Plastic hinge capacity members evaluated considering flexure (M), axial force (N) shear (V) interaction validated procedur...

An experimental and numerical study of impinging, incompressible, axisymmetric, laminar jets is described, where the jet axis of symmetry is aligned normal to the wall. Particle streak velocimetry (PSV) is used to measure axial velocities along the centerline of the flow field. The jet-nozzle pressure drop is measured simultaneously and determines the Bernoulli velocity. The flow field is simul...

Overwhelming evidence has accumulated in recent years that supernova explosions are intrinsically 3-dimensional phenomena with significant departures from spherical symmetry. We review the evidence derived from spectropolarimetry that has established several key results: virtually all supernovae are significantly aspherical near maxim light; core-collapse supernovae behave differently than ther...

A model of the Bose-Einstein condensate (BEC) of dipolar atoms, confined in a combination of a cigar-shaped trap and optical lattice acting in the axial direction, is studied in the framework of the one-dimensional (1D) nonpolynomial Schrödinger equation (NPSE) with additional terms describing long-range dipoledipole (DD) interactions. The NPSE makes it possible to describe the collapse of loca...

This report describes an experimental and numerical study of impinging, incompressible, axisymmetric, laminar jets, where the jet axis of symmetry is aligned normal to the wall. Particle Streak Velocimetry (PSV) is used to measure axial velocities along the centerline of the flow field. The jet-nozzle pressure drop is measured simultaneously and determines the Bernoulli velocity. The flowfield ...

Photo acoustic drug delivery is a technique for localized drug delivery by laser-induced hydrodynamic pressure following cavitation bubble expansion and collapse. Photoacoustic drug delivery was investigated on gelatin-based thrombus models with planar and cylindrical geometries by use of one microsecond laser pulses. Solutions of a hydrophobic dye in mineral oil permitted monitoring of deliver...