Thermo-electro-hydrodynamic instabilities in a dielectric liquid under microgravity

Linear stability analysis of a dielectric fluid confined in a cylindrical annulus of infinite length is performed under microgravity conditions. A radial temperature gradient and a high alternating electric field imposed over the gap induce an effective gravity that can lead to a thermal convection even in the absence of the terrestrial gravity. The linearized governing equations are discretized using a spectral collocation method on Chebyshev polynomials to compute marginal stability curves and the critical parameters of instability. The critical parameters are independent of the Prandtl number, but they depend on the curvature of the system. The critical modes are non-axisymmetric and are made of stationary helices.

► We analyze the dielectrophoretic effect on the stability of a dielectric liquid.
► The liquid is confined in annular gap.
► Collocation method with 60 Chebyshev polynomial is used.
► Critical modes are stationary helical vortices.
► Critical parameters depend on flow curvature but not on fluid nature.