S .Raghunathan, D. Mitchell and M. Gillan, Department of Aeronautical Engineering, Queens University Belfast, Belfast. United Kingdom
K.Tease, Applied Research Technology, Inverness, Scotland, United Kingdom
Abstract
Techniques for simulating the flow over a large scale prototype on small scale models are discussed. Typical results from the Wells turbine tests are presented. The need for considerable research effort in this area is highlighted.
Introduction
Lancaster (1907) a famous Aeronautical Engineer, who said "If a blue-bottle was to find itself suddenly transferred to a common fly (smaller in size) but with the same geometric properties as a blue-bottle, it would suddenly discover that the air is more sticky and difficult to fly". Lancaster was indicating that fluid friction
on a smaller scale could be significantly larger than that on a large scale.
The main difference in aerodynamic forces between a small and a large scale is due to the lack of dynamic similarity of viscous fluid motion, which is a ratio of inertia forces to viscous forces on a body in a moving fluid.
In recent years there has been considerable interest in this area, particularly to aerodynamicists. There have been methodologies developed for of simulation of flow over large scale bodies with small scale tests. An objective of this paper is to highlight these methodologies for Wells turbine researchers. Acomparison of tests
on the Wells turbine at several scales and using some of the simulation methodologies are also be discussed. The paper shows the need for considerable research effort in this area considering the prediction of the performance of large scale Wells turbines for wave energy conversion is a key issue at present.
ENVIRONMENTAL EFFECTS ON A STRUCTURALLY DENSE JACKET PLATFORM MODEL
Sub rata K. Chakraharti, CBI Technical Services Co., Plainfield, IL 60544
George Z. Gu, MEPTEC, Mobil Technology Company, Dallas, TX75244
ABSTRACT
The wave loading due to high storm waves is an important consideration in the re-qualification and upgrading of older Gulf of Mexico jackets. In particular, due to dense population of members in these jackets, blockage and shielding are important parameters. Experiments in regular waves and uniform current showed that the presence of current in waves substantially increases the blockage effect from these members. API-RP2A recommendation for blockage factor in current matches the test data well.
