Dynamics of a Vapour Bubble inside a Vertical Rigid Cylinder

In this Paper dynamics of a vapour bubble generated due to a local energy input inside a vertical rigid cylinder and in the absence of buoyancy forces is investigated. Different ratios of the rigid cylinder to the maximum radius of the bubble are considered. The Boundary Integral Equation Method is employed for numerical simulation of the problem. Results show that during the collapse phase of the bubble inside a vertical rigid cylinder, two liquid micro jets are developed on the top and bottom sides of the vapour bubble and are directed inward. Results also show that existence of a deposit rib inside the vertical rigid cylinder slightly increases the life time of the bubble. It is found that by increasing the ratio of the cylinder diameter to the maximum radius of the bubble, the rate of the growth and collapse phases of the bubble increases and the life time of the bubble decreases

Simplistic vs. Complex Organization: Markets, Hierarchies, and Networks in an 'Organizational Triangle'

Transaction cost economics explains organizations in a simplistic ‘market-vs.-hierarchy’ dichotomy. In this view, complex real-world coordination forms are simply considered ‘hybrids’ of those ‘pure’ and ideal forms, thus being located on a one-dimensional ‘line’ between them. This ‘organizational dichotomy’ is mainly based on relative marginal transaction costs, relative lengths of value-added chains, and ‘rational choice’ of coordination form. The present paper, in contrast, argues that pure ‘market’ and ‘hierarchy’, even including their potential hybrids, are a theoretically untenable and empirically void set. Coordination forms, it is argued, have to be conceptualized in a fundamentally different way. A relevant ‘organizational space’ must reflect the dimensions of a complex world such as dilemma-prone direct interdependence, resulting in strong strategic uncertainty, mutual externalities, collectivities, and subsequent emergent process. This, in turn, will lead either to (1) informally institutionalized, problem-solving cooperation (the instrumental dimension of the institution) or (2) mutual blockage, lock-in on an inferior path, or power- and status-based market and hierarchy failure (the ceremonial dimension of the institution). This paper establishes emergent instrumental institutionalized cooperation as a genuine organizational dimension which generates a third ‘attractor’ besides ‘market’ and ‘hierarchy’, i.e., informal network. In this way, an ‘organizational triangle’ can be generated which may serve as a more relevant heuristic device for empirical organizational research. Its ideal corners and some ideal hybrids on its edges (such as ideal clusters and ideal hub&spoke networks) still remain empirically void, but its inner space becomes empirically relevant and accessible. The ‘Organizational Triangle’ is tentatively applied (besides casual reference to corporate behavior that has lead to the current financial meltdown), by way of a set of criteria for instrumental problem-solving and a simple formal algorithm, to the cases of the supplier network of ‘DaimlerChrysler US International’ at Tuscaloosa, AL, the open-source network Linux, and the web-platforms Wikipedia and ‘Open-Source Car’. It is considered to properly reflect what is generally theorized in evolutionary-institutional economics of organizations and the firm and might offer some insight for the coming industrial reconstructions of the car and other industries

Numerical investigation on the pulsating bubble dynamics in a narrow cylinder with a compliant coating

10.1088/0169-5983/46/1/015513Fluid Dynamics Research461-FDRS

Numerical analysis of a cavitation bubble in the vicinity of an elastic membrane

10.1088/0169-5983/45/5/055503Fluid Dynamics Research455-FDRS