A Potential Flow Model for the Drag of Shrouded Cylinders

✍ Scribed by B. Molin

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 260 KB
• Volume: 7
• Category: Article
• ISSN: 0889-9746
• DOI: 10.1006/jfls.1993.1003

✦ Synopsis

Vortex-induced vibrations of cylinders can be efficiently reduced by fitting them with perforated shrouds, at the expense, however, of increased drag. So far, optimization of the geometric parameters, such as the cylinder gap, the open-area ratio, and the shape of the openings, have been based on experimental investigations only.

An asymptotic theoretical analysis is presented here, where the shroud openings are assumed to be infinitely small, and where potential theory is assumed to hold in the fluid domains on either side of the shroud. Comparisons with available experimental data show that the loading on the shroud is reasonably well predicted. The load on the inner cylinder is found always to be negative, that is opposite to the current direction, a feature that has been observed experimentally in some instances. Computational results for the loading on the shroud and cylinder are given for wide ranges of open-area ratios and cylinder gaps.