Vortex shedding from a circular cylinder in a smooth and wired configuration: comparison between 3D LES simulation and experimental analysis

Abstract Vortex shedding from cylindrical structures with circular section is a widely studied phenomenon since this problem is of interest with respect to many technical applications. By means of experimental tests, many aspects of this very complex topic have been investigated and several devices have been studied in order to reduce the forcing induced by fluid-structure interaction. A particular device, consisting of two wires, having a diameter smaller than that of the cylinder, helically wrapped around the cylinder itself, will be analysed in this paper. Devices like this, whose main idea is to disorganise or modify the flow field near the cylinder surface, are already used in different technical applications such as in civil applications (slender towers, smokestacks) or in maritime applications (pipelines or risers) to take only a few examples. The efficacy of this solution has been investigated, in this paper, both by experimental tests and by numerical simulations. Experimental tests have been carried out in a water channel located at Politecnico di Milano and have produced data for a velocity range that covers Reynolds numbers from 2×10 4 to 4×10 4 . Numerical simulations, performed by using a commercial CFD code (FLUENT) with a large eddy simulation (LES) approach, have been feasible only for the lowest values of the Reynolds number, due to the large computational power required for these kinds of applications. Simulations have been performed for a 2D and a 3D configuration and have been compared with experimental results.