Greg Lilik Due: 5/1/07 EGEE 520 Abstract Hydrogen is currently being examined as a transportation fuel. One example of the way in which hydrogen has been examined is in diesel pilot ignited hydrogen combustion. This is achieved by injecting hydrogen into the air intake of an engine. The mixing of fuel and air greatly effect the polluting emission created during combustion. The hydrogen and air ...

For the understanding of planetary and stellar dynamos an overview of the major parameter dependences of convection driven dynamos in rotating spherical fluid shells is desirable. Although the computationally accessible parameter space is limited, earlier work is extended with emphasis on higher Prandtl numbers and uniform heat flux condition at the outer boundary. The transition from dynamos d...

A generalization of Kraichnan’s model of passive scalar advection is considered. Physically motivated regularizations of the model are considered which take into account both the effects of viscosity and molecular diffusion. The balance between these two effects on the inertial range behavior for the scalar is shown to be parameterized by a new turbulent Prandtl number. Three different regimes ...

The linear stability of the dissipative Taylor-Couette flow with an azimuthal magnetic field is considered. Unlike ideal flows, the magnetic field is a fixed function of a radius with two parameters only: a ratio of inner to outer cylinder radii, eta, and a ratio of the magnetic field values on outer and inner cylinders, muB. The magnetic field with 0<muB<1/eta stabilizes the flow and is called...

There is a surprisingly substantial amount of aerosol mixing and deposition deep in the lung, which cannot be explained by classic transport mechanisms such as streamline crossing, inertial impaction, or gravitational sedimentation with reversible acinar flow. Mixing associated with "stretch and fold" convective flow patterns can, however, be a potent source of transport. We show such patterns ...

A new turbulence model suited for calculating the turbulent Prandtl number as part of the solution is presented. The model is based on a set of two equations: one governing the variance of the enthalpy and the other governing its dissipation rate. These equations were derived from the exact energy equation and thus take into consideration compressibility and dissipation terms. The model is used...

A linear stability analysis is applied to determine the onset of oscillatory thermocapillary convection in cylindrical liquid bridges of large Prandtl numbers (4 6 Pr 6 50). We focus on the relationships between the critical Reynolds number Rec, the azimuthal wave number m, the aspect ratio Γ and the Prandtl number Pr. A detailed Rec-Pr stability diagram is given for liquid bridges with various...

We report for the first time a laminar high-performance continuous micromixing process of two fluids over a length of 200 microns in under 10 milliseconds achieved by an optimization of the control parameters amplitude and frequency in the mixing device denoted as 'Shear Superposition Micromixer'. We improve mixing time by approximately 5 orders of magnitude over diffusion-limited mixing. The d...

Abstract. We discuss the advantages and results of using a mixing-length, compressible model to account for shear banding behaviour in granular flow. We formulate a general approach based on two function of the solid fraction to be determined. Studying the vertical chute flow, we show that shear band thickness is always independent from flowrate in the quasistatic limit, for Coulomb wall bounda...

In their natural environment, phytoplankton are exposed to fluctuations in incident irradiance due to vertical displacements in the water column induced by turbulent fluid motion. Physiological adaptation to these fluctuations results in variation in a number of measurable quantities (e.g. parameters of P-I curves, fluorescence yield, chemical composition), each of which have different time-sca...