On spatial instability of an electrically forced non-axisymmetric jet with curved centerline

This paper considers the problem of spatial instability of an electrically forced non-axisymmetric jet with curved centerline. A mathematical model, which is developed for the spatially growing oscillations of the centerline of the jet, is based on the relevant approximated versions of the equations of the motion for such electrically forced jet flow. The approximations include the assumptions that the radius of curvature of the centerline of the jet is much larger than the radius of the jet and the spatially growing disturbances are infinitesimal in amplitude. For the neutral temporal stability boundary, we identify, in particular, new spatial, conducting and viscous modes of instabilities which travel axially in the direction of increasing axial variable and are enhanced with increasing either the surface charge or the strength of the applied electric field. For given values of the parameters, there is a critical wave number at which the instability of these modes is maximized. The range of values of the wave number and the frequency of these instability modes increases with the externally imposed electric field.