Numerical investigation of an influence of square cylinder crossovers on twin bare hulls in close proximity

Abstract

This paper investigates the influence of two crossovers on twin bare spheroids in close proximity. Firstly, to examine the impact of the crossovers to the flow behaviour and overall drag coefficient of spheroids. Secondly, to compare the drag coefficient for various speeds. The CFD RANS-SST with a commercial code ANSYS CFX simulation is performed for the fully submerged twin spheroids with transverse separation (S/D) of 1.02; where S is the distance between centreline to centreline and D is the maximum diameter of a spheroid. The Reynolds Numbers used are 2 × 106, 3 × 106, and 4 × 106. The results show that each spheroids experience an additional 20% drag which is dominated by crossovers. The drag coefficient of small volume crossovers between spheroids is 10 times higher than the drag of each spheroids, consequently, the total drag of system is increased by 11 times compares to twin bare spheroids system. Increasing speed results in the drag reduction. At the Reynolds Number 2 × 106 shows the highest drag coefficient of twin hulls for both cases (with or without crossovers). The result suggests the use of twin bare hulls without crossovers in the fleet, an application; for example, a fleet of small autonomous underwater vehicles.

12 Figures and Tables

Cite this paper

@inproceedings{Rattanasiri2016NumericalIO, title={Numerical investigation of an influence of square cylinder crossovers on twin bare hulls in close proximity}, author={Pareecha Rattanasiri and P. A. Wilson}, year={2016} }