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OCLC produces a number of products for CD‐ROM, derived variously from public domain databases in the US, such as ERIC, AGRICOLA and NTIS, and from subsets of its own massive 18,500,000 record Union Catalog. The initial set covered three main subject areas: Education; Agriculture; and Science and Technology. The CD‐products are referrred to as Search CD450 and are intended to support reference work and access to subject information. In addition, a CD‐ROM based cataloguing product has been developed: its suitability in the UK and Europe is currently being evaluated by OCLC Europe. Towards the end of 1987, OCLC set up an evaluation project at King's College Library, University of London, to assess the ERIC databases produced as part of the Search CD450 products. This article describes the broad findings of that project together with the facilities offered by CD450.

The exponential growth in computational capabilities and the increasing reliability of current simulation tools have fostered the use of computational fluid dynamics (CFD) in the design of pioneering aircraft engine architectures, such as the counter rotating open rotor (CROR) engine. Today, this design process is led by tight performance and noise constraints from a very early stage, thus requiring deep investigations of the aerodynamic and acoustic behaviour of the fluid flow. The purpose of this study is to track the trajectory of tip vortices, which is of critical importance to understand and prevent potential vortex–blade interactions with subsequent rows, as this condition strongly influences the aerodynamic and structural performance and acoustic footprints of the engine.

In this paper, a flow feature detection methodology is applied to a particular CROR test case with the goal of visualizing and tracking the development of these coherent structures from the tip of front rotating blades. The suitability and performance of four typical region-based methodologies and one line-based (LB) criteria are firstly evaluated. Then, two novel seeding methodologies are presented as an attempt to improve the performance of the LB algorithm previously investigated.

It was demonstrated that the new seeding algorithms increase the probability of the selected seeds to grow into a tip vortex line and reduce the user’s dependence upon the selection of candidate seeds, providing faster and more accurate answers during the design-to-noise iterative process.

Apart from the new vortex detection initialization methodologies, the paper also attempts to assist the user in the endeavour of extracting rotating structures from their own CFD simulations.