Recently, Dr. Qingzhen Yang from BEBC has published a research paper in International Journal of Heat and Mass Transfer entitled "Electrohydrodynamic Rayleigh-Taylor instability in leaky dielectric fluids".

Rayleigh-Taylor instability (RTI) is a phenomenon that takes place at the interface of two stratified immiscible fluids when the denser fluid placed over the lighter one under the action of gravity, where gravity force breaks the equilibrium at the interface. In this paper, the authors presented an analysis of the influence of electric field on the Rayleigh-Taylor instability (RTI) of two leaky dielectric fluids. A numerical model is developed based on the coupled solution of the governing equations of the electric field (i.e., Poisson equation) and the fluid flow (i.e., Navier-Stokes equation), where the leaky dielectric model is employed to take into account the free charges in the fluids. These equations are formulated within the framework of phase field and solved simultaneously. The numerical model is applied to study the effect of the electric field on interfacial morphology associated with the RTI. Various interfacial morphologies have been observed in the electrohydrodynamic RTI, suggesting that the electric field has a significant influence on the RTI. An electric field (horizontal or vertical) may suppress or aggravate the instability depending on the system parameters the permittivity ratio and the conductivity ratio of the two leaky dielectric fluids.

Bioinspired Engineering and Biomechanics Center (BEBC) focuses on how to create proper microenvironment for cells in vitro. Hydrogels and other polymers are good candidates for cell culture. Thus we are interested in the instability phenomena that may occur during polymers fabrication and this is the motivation of this paper. The authors of this paper include Dr. Qingzhen Yang from BEBC, Prof. Ben Li from University of Michigan-Dearborn and also the Chair of BEBC, Prof. Feng Xu. This work is financially supported by the NSFC (51605377, 11522219, 11372243).

Article Link: http://www.sciencedirect.com/science/article/pii/S0017931016324620