Electrohydrodynamically driven chaotic mixing in a translating drop

When a liquid drop of given dielectric constant, resistivity and viscosity is translating in the presence of an electric field in a liquid of differen t dielectric constant, resistivity and viscosity, the resulting internal ci rculation is a superposition of the Hadamard-Rybcynski and Taylor (quadrapo le) circulations. For sufficiently large field strengths, the quadrapole st ructure of the Taylor flow causes an internal stagnation disk to occur. Whe n this flow field is modulated by an ac component of the electric field, at low Stokes numbers, the resulting Lagrangian particle trajectories can exh ibit chaotic behavior. This Lagrangian chaos is examined via Poincare maps and both the degree and rates of mixing are studied for a wide range of fie ld strengths and modulation frequencies. (C) 2001 American Institute of Phy sics.