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The process of formation of air core and its development with time, inside one cylindrical and one conical nozzle having two tangential entries, has been analyzed experimentally and numerically. Experiments have been carried out using Plexiglas nozzles and water in ambient air; the air core has then been photographed for different nozzles and flow parameters. Numerical simulations have been performed using a finite volume method that employs unstructured grids with cell-wise local refinement and an interface-capturing scheme to predict the shape of the air core. The shape of the air core inside the cylindrical nozzle is found to be helicoidal at steady state for higher inlet velocity, whereas the shape of the free surface remains nearly cylindrical for low inlet velocity. In the conical nozzle, the air core is nearly axisymmetric in experiments. So only two-dimensional simulations are performed; the air core widens at the end of conical section as it approaches nozzle exit. For both nozzles numerical simulation predicts qualitatively and to a large extent also quantitatively the correct shape of the air core and the angle of the spray at the nozzle exit, as verified by comparisons with experimentally observed shapes. [DOI: 10.1115/1.1412845]

A newly developed finite volume method was applied to ship slamming. The computational method accounts for arbitrary free surface deformations and uses unstructured grids for the discretization of the domain. A linear panel method was used to predict motions of a modern 2400 TEU container ship. Resulting relative velocities at the ship's keel were used to estimate the maximum vertical re-entry velocities at the bow in North Atlantic wave conditions. Water entry of three bow sections was numerically simulated to determine pressures at the bow flare. Prescribed vertical velocity histories significantly affected the determination of realistic pressure levels.

The present paper concerns numerical investigation of a piston-driven, axisymmetric flow in a pipe assembly containing a sudden expansion. The piston closes the larger of the two pipes. The impulsively starting intake flow is the topic of this investigation. Results of numerical calculations and laser-Doppler measurements are presented to provide an insight into the features of the flow. The calculation procedure employed in this study is based on a finite-volume method with staggered grids and SIMPLE-algorithm for pressure-velocity coupling (Patankar and Spalding, 1972). The convection and diffusion fluxes in the Navier-Stokes equations are discretized with first order upwind and second order central differences, respectively. A fully implicit Euler scheme is used to discretize the temporal derivatives. The Navier-Stokes equations were suitably transformed to allow prediction of the flow within the inlet pipe (fixed grid) and cylinder region (moving grid) simultaneously (once-through procedure). Laser-Doppler measurements of both axial and radial velocity components were performed. Refractive index matching was used to eliminate the wall curvature effects. For each measuring point 20 cycles were measured, showing high repetition rates. Comparison of measured and predicted velocity profiles shows good agreement.

Type 2 diabetes mellitus (T2DM) increases cardiovascular complications. Diabetic vascular dysfunction is associated with the reduced activity of the different smooth muscle potassium (K+) channels. Thus, the objective of our study was to investigate the role of the adenosine triphosphate (ATP)-sensitive K+ (KATP) channels in the relaxant effect of potassium channel opener, pinacidil on the human saphenous vein (HSV) obtained from the patients with and without T2DM. The rings of HSV without the endothelium, obtained from the patients who had undergone coronary bypass surgery, were mounted in an organ bath system and isometric tension was recorded. The relaxation of HSV, precontracted with phenylephrine, was produced by pinacidil. The expression of KATP subunits (Kir6.1, Kir6.2 and SUR2B) was detected by immunohistochemistry and Western blot. Pinacidil produces comparable effects on HSV in patients with and without T2DM. The suppression of pinacidil effect and its maximal relaxation by glibenclamide, selective blocker of KATP channels, was more pronounced on HSV in patients without T2DM. All three types of KATP subunits are expressed on the smooth muscle cells of HSV. While there are no differences in the expression of Kir6.1 and Kir6.2, the expression of SUR2B is lower in HSV in patients with T2DM. Pinacidil produced comparable KATPdependent and -independent relaxation of the HSV in patients with/without T2DM. According to the effect of glibenclamide and the applied molecular analysis, presented findings demonstrated that diabetes mellitus was associated with the reduced expression of SUR2B subunit in the vascular smooth muscle of HSV. [ABSTRACT FROM AUTHOR]

Potential energy surfaces for the electronic states of the CCCH radical correlating at linear nuclear arrangement with the X[SUP2]II state are calculated by means of an extensive ab initio approach. They are used to compute the vibronic and spin-orbit structure of this electronic state by means of a variational approach based on the use of normal bending coordinates. The results of calculations enable a reliable interpretation of the available experimental data and offer explanation for several apparently peculiar features observed. [ABSTRACT FROM AUTHOR]

Potential energy surfaces for the electronic states of the HCCS radical correlating at linear nuclear arrangement with the A [sup 2]Π state are calculated by means of an extensive ab initio approach. They are used to compute the vibronic and spin-orbit structure of the A [sup 2]Π-X[sup 2]Π electronic transition. These calculations are carried out by means of a new variational approach based on the use of normal bending coordinates. The results of calculations question various interpretations of the available experimental data; on the other hand they do not offer reliable explanation of all features observed, pointing in this way at the shortages of the present, as well as of previous theoretical handling of the problem in question. [ABSTRACT FROM AUTHOR]