Continuum Feedback Control of Instabilities on an Infinite Fluid Interface

Field‐coupled Rayleigh‐Taylor instabilities on a fluid interface can be suppressed by means of feedback. Deflections of the interface are detected to provide a signal which is amplified and fed back to a structure coupled to the interface through the fields. A theoretical study is given of the conditions for stability of an infinite interface coupled to an active structure through a perpendicular electric field and a tangential magnetic field. In both cases the interface is assumed to be perfectly conducting. A traveling wavetrain analysis is used to show the regimes of stability as they depend on the Taylor wavelength, electric or magnetic pressure, feedback gain, and technique of sampling interface deflections. Emphasis is given to the effect of feedback derived from detecting surface deflections averaged over a sampling area and feeding back to that same area.