A nonlinear mathematical model with a free moving boundary was introduced to study viscous flow in stenotic elastic tubes subject to a prescribed external pressure at the tube wall and pulsatile pressure drop between the tube inlet and outlet. An iterative numerical method using boundary iteration, pseudocompressibility, and the ADI technique was developed to solve the model. Unsteady effects o...

The energy transfer mechanisms and structures playing a role in these adverse-pressure-gradient (APG) turbulent boundary layers (TBLs) with small large velocity defects are investigated. We examine the wall-normal spectral distributions of energy, production pressure-strain APG TBLs compare those canonical flows. It is found that not profoundly affected by an increase defect, although spectra d...

Right ventricular function before and during 10 days of mild pressure loading (10 mm Hg increase in mean pulmonary arterial pressure) was compared with right ventricular function in unloaded near-term fetal sheep. Pressure loading did not alter fetal arterial blood gases or vascular pressures. The right ventricular function curve (stroke volume versus mean right atrial pressure) was not signifi...

BACKGROUND AND PURPOSE Computational fluid dynamics modeling is useful in the study of the hemodynamic environment of cerebral aneurysms, but patient-specific measurements of boundary conditions, such as blood flow velocity and pressure, have not been previously applied to the study of flow-diverting stents. We integrated patient-specific intravascular blood flow velocity and pressure measureme...

This paper presents a model for predicting pressure losses in foams of various expansions and pressures, in pipes of any given diameter, once the foam behavior has been characterized at a single expansion and pressure. The model incorporates a modified form of the power-law viscosity model of foam, which is obtained through the method of volume equalization. Since apparent wall slip contributes...

A mathematical model of Peristaltic pumping of a particle-fluid suspension in a circular tube with an inserted catheter has been developed. The coupled differential equations for both the fluid and the particle phases have been solved and the expression for the flow rate, pressure drop, friction forces at the tube and the catheter wall have been derived. It is found that the pressure drop incre...

The volumetric elastic modulus of the cell wall and the hydraulic conductivity of the cell membranes were measured on ligatured compartments of different sizes of Chara corallina internodes using the pressure probe technique. The ratio between intact cell surface area and the area of puncture in the cell wall and membrane introduced by the microcapillary of the pressure probe was varied over a ...

This study was designed to quantitate the influence of 20 clinical, hemodynamic, and volume determinants of left ventricular (LV) structure. Systemic hemodynamics, intravascular volume, and LV echocardiographic measurements were collected in a heterogeneous population of 171 patients. Stepwise multiple-regression analysis indicated that body weight and body-surface area were the most powerful d...

The relation between left ventricular wall thickness and mass, arterial plasma catecholamines, and blood pressure at rest and during a mental arithmetic challenge and a cold pressor test was examined in 69 healthy men 19 years of age. The subjects were recruited from the 1st (n = 21), 50th (n = 26), and 99th (n = 22) percentiles in mean blood pressure. All underwent echocardiography to determin...

1. Renal hypertension produces a marked and rapidly detectable hypertrophy of the rat aorta, due to smooth muscle cell hyperplasia and connective tissue deposition. 2. As we described previously for collagen synthesis, cell hyperplasia is a very early event which reaches a maximum at a time when the blood pressure is far from its highest level, and thereafter progressively decreases. 3. Reserpi...