NONSYMMETRIC BRANCHING OF FLUID FLOWS IN 3D VESSELS

Nonsymmetric branching flow through a three-dimensional (3D) vessel is considered at medium-to-high flow rates. The branching is from one mother vessel to two or more daughter vessels downstream, with laminar steady or unsteady conditions assumed. The inherent 3D nonsymmetry is due to the branching shapes themselves, or the differences in the end pressures in the daughter vessels, or the incident velocity profiles in the mother. Computations based on lattice-Boltzmann methodology are described first. A subsequent analysis focuses on small 3D disturbances and increased Reynolds numbers. This reduces the 3D problem to a two-dimensional one at the outer wall in all pressure-driven cases. As well as having broader implications for feeding into a network of vessels, the findings enable predictions of how much swirling motion in the cross-plane is generated in a daughter vessel downstream of a 3D branch junction, and the significant alterations provoked locally in the shear stresses and pressures at the walls. Nonuniform incident wall-shear and unsteady effects are examined. A universal asymptotic form is found for the flux change into each daughter vessel in a 3D branching of arbitrary cross-section with a thin divider.

Evaluation of Oil Viscosity Influence on Hydraulic Shock in Long Pipe

This article is aimed at mathematical simulation and experimental measurement of dynamics of liquid and pipe wall during hydraulic shock. Liquid compressibility and hydraulic line elasticity are taken into account in this case. The mathematical model is created using Matlab SimHydraulics software. The long pipe is simulated by means of segmented pipe. Experimental measurement is performed on a hydraulic system, which consists of flow-controlled aggregate, long pipe and seat valve. The hydraulic shock is caused by step closing of the seat valve that is located at the pipe end. Pressures at the end of the long pipe, oil flow and temperature are experimentally measured.

ENGINEERING ASPECTS OF MILKING MACHINE RESEARCH

Summary Research was undertaken to learn more precisely the physical aspects of mechanical milking. Attempts to measure the instantaneous flow rate have not been successful. A technique to measure precisely the vacuum at the teat end was developed and several measurements made. The work indicates previous assumptions regarding teat end pressures may have been in error. Limited work to date indicates a need for continuing efforts.

SOME FACTORS AFFECTING THE AUSCULTATORY MEASUREMENT OF ARTERIAL BLOOD PRESSURES

Auscultatory blood pressure measurements have been compared to intraarterial lateral and end pressures. It was found that auscultatory measurements, which are dependent upon the penetration of pulse waves through a compressed segment of artery, were influenced by various factors. When auscultatory measurements approximated or exceeded intra-arterial pressures, broad pulses were found; when auscultatory measurements were below intraarterial pressures, narrow pulses were found. By measuring tissue pressures under a cuff it was shown that cuffs subtended only a relatively short narrow band of equal pressure into the tissues. Hence narrow cuffs or, conversely, large arms that allowed only a fraction of the applied pressure to reach the artery caused high auscultatory measurements of both systolic and diastolic pressure. It was concluded that pulse contour and arm size were major causes of the auscultatory systolic errors while the diastolic errors were due to arm size plus unknown factors.