Geometrical and kinematic properties of interfacial waves in stratified oil-water flow in inclined pipe

The stratified oil-water flow pattern is common in the petroleum industry, especially in offshore directional wells and pipelines. Previous studies have shown that the phenomenon of flow pattern transition in stratified flow can be related to the interfacial wave structure (problem of hydrodynamic instability). The study of the wavy stratified flow pattern requires the characterization of the interfacial wave properties, i.e., average shape, celerity and geometric properties (amplitude and wavelength) as a function of holdup, inclination angle and phases' relative velocity. However, the data available in the literature on wavy stratified flow is scanty, especially in inclined pipes and when oil is viscous. This paper presents new geometric and kinematic interfacial wave properties as a function of a proposed two-phase Froude number in the wavy-stratified liquid-liquid flow. The experimental work was conducted in a glass test line of 12 m and 0.026 m id., oil (density and viscosity of 828 kg/m(3) and 0.3 Pa s at 20 degrees C, respectively) and water as the working fluids at several inclinations from horizontal (-20 degrees, -10 degrees, 0 degrees, 10 degrees, 20 degrees). The results suggest a physical relation between wave shape and the hydrodynamic stability of the stratified liquid-liquid flow pattern. (C) 2011 Elsevier Inc. All rights reserved.

Drawing and surface: freehand architectural drawing mediated by digital

This paper discusses the redefinition of the function of freehand drawing in the design process in view of intuitive digital media. It sets forth an interpretive analysis of an experiment with drawing on opaque tablets, carried out with a group of students of the Instituto de Arquitetura e Urbanismo da Universidade de São Paulo. After a brief review of the current debate on freehand drawing and the advent of digital media, we examine the experiment as a possible way to elicit facts that may contribute to the discussion. To this end, our research has concentrated on the intuitive use enabled by existing digital media. It is our intention that this empirical approximation becomes a pilot experiment for the use of digital tablets in the process of construction the gaze of the student in Architecture and Urbanism as a reflection on the different cognitive dimensions that constitute the practice of drawing and its reinterpretation to develop new ideas.