Cylinder wake control by magnetics fields in liquid metal flows


Cylinder wake control by magnetics fields in liquid metal flows

Mutschke, G.; Shatrov, V.; Gerbeth, G.

In the present paper we are concerned with the control of wake instabilities in the flow of an electrically conducting fluid around a circular cylinder by means of external magnetic fields. Besides the Reynolds number (Re) a second parameter N appears describing the strength of the magnetic body force. This offers, depending on the direction of the magnetic field, a large variety of flow configurations and therefore different transition regimes. We perform a numerical simulation of the unsteady two-dimensional flow and characterize the different flow regimes. Strong magnetic fields are capable to stabilize the 2-D flow and to suppress the shedding of vortices. We present curves of neutral 2-D stability in the (Re,N)-parameter plane separating steady and periodic flow regimes. We further perform a linear 3-D stability analysis of the 2-D flow being either steady or periodic and show how the magnetic field influences the 3-D instabilities. We pay special attention to the case when the magnetic field is aligned with the oncoming flow. Here we find 3-D instability in parameter regions above the 2-D stability curve in the (Re, N)-plane where the flow is 2-D stable (steady). This firstly confirms a general result of Hunt (J.C.R. Hunt, Proc. Roy. Soc. A 293 (1966) 342) obtained from a stability analysis of parallel flows and shows that the magnetic field influences 2-D and 3-D instabilities in a different way.

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Publ.-Id: 1965