Electrohydrodynamic Phenomena Research Paper

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Electrohydrodynamic Electrohydrodynamic Phenomena The EHD phenomena involve the interaction of electric fields and flow fields in a dielectric fluid medium. This interaction can result in electrically induced fluid motion and interfacial instabilities which are caused by an electric body force. The electric body force density acting on the molecules of a dielectric fluid in the presence of an electric field consists of three terms (1): f_e=ρ_e E ̅-1/2 E^2 ∇ε+1/2 ∇[ρE^2 (δε/δρ)_T ] (1) The three terms in Eq (1) stand for two primary force densities acting on the fluid. The first term represents the force acting on the free charges in the presence of an electric field and is known as the Coulomb force. The second and third terms represent the polarization force induced in the fluid. Figure 1 shows four examples of induced forces on a dielectric fluid medium, which can result from the application of a nonuniform electric field. The electric body force density components defined in Eq. (1) are responsible for the induced forces on the dielectric fluid medium. Schematic (a) in Figure 1 is a representation of fluid …show more content…

The fluid can be inhomogeneous, in the sense that the permittivity is a function of position, or it can vary with density. The second term in Eq. (1) is due to inhomogeneities, while the last term is due to variations in the fluid density. Since the last term provides a coupling between the fluid density and the electric field, it is called the electrostriction force density. Discussion has persisted whether or not the electrostriction force density term in Eq. (1) can be responsible for the translational motion of an induced dipole as shown in schematic (b) of Figure 1. A more detailed discussion on polarization forces and the potential of the electrostriction force density to generate fluid translation is provided by Bryan

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