Spray cooling is a topic of current interest for its ability to uniformly remove high levels of waste heat for densely packed microelectronics. A Monte-Carlo (MC) spray cooling simulation model is under development that is based on empirical data to be a cost effective design tool that will predict accurate heat fluxes based on nozzle conditions and heater geometry. This work reports spray and single drop experiments with the goal of computing the volume beneath a drop impact cavity (sub-cavity volume) created by a single impinging droplet on an initial liquid layer. A relevant test plan for the single drop experiments in terms of We and Re numbers was created through utilization of Phase Doppler Anemometry to characterize a water spray generated by a nozzle of interest for varying flow conditions. Liquid thickness profiles of the sub-cavity formed by a single impinging drop onto a range of initial liquid film thicknesses were measured versus time via a non-contact optical thickness sensor. Time dependent sub-cavity volumes were computed by integrating these sub-cavity liquid film thickness profiles measured radially outward from the impact centerline. It is found that higher We and lower h 0 * result in a more radially uniform sub-cavity surface contour versus time, except for regions near the outer bottom cavity radius, where the liquid film was thinner. The sub-cavity volume was found to be nearly constant for a majority of the cavity lifetime and increased with We and h 0 * . These results will be incorporated in future work into the MC model to improve its predictive capability. Nomenclatured = Drop diameter Greek Letters D = Arithmetic mean droplet diameter ρ = Density D 32 = Sauter mean droplet diameter η = Index of refraction Fr = Froude number = μ = Dynamic viscosity h = Liquid film thickness σ = Surface tension R = Radial location τ = Dimensionless time (t•V axial /d) Re = Reynolds number = Superscripts T = Temperature * = Dimensionless parameter t = Time Subscripts V = Arithmetic mean velocity 0 = Initial condition Vol = Sub-cavity volume axial = Axial velocity component We = Weber number = c = Cavity z = Axial standoff distance from the nozzle tip r = Radial velocity component s = Spray

Accurate models for the prediction of ship airwake flowfields are critical to the development of realistic flight simulation tools for aircraft carrier launch and recovery operations. The accurate computation of the ship airwake can be very challenging due to the complexity of the ship geometry, the size of and difficulty in generating a suitable computational mesh, and the large range of length and time scales present in the unsteady flowfield. The present paper investigates the sensitivity of the airwake solution to several modeling parameters, including geometric complexity and the resolution of boundary layers, with the aim of determining the level of fidelity required to obtain an accurate solution.Results are compared to wind tunnel experimental measurements. The results of these studies show that, in general, a majority of the airwake flow features are characterized by bluff body shedding from the larger geometric entities that comprise the ship geometry. Depending on the requirements and intended use of the solution, a certain tradeoff can be reached between solution turn-around/grid generation time and solution accuracy.

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A study of the total energy of an isolated impurity in an extended substrate is presented. The approach is based on the Green's function embedding method within the density functional theory framework. We explicitly take care of the influence of an infinite substrate and introduce the contributions to the total energy of an isolated impurity deriving from long range charge density oscillations. Total energies for a substitutional Al atom in Mg and Na bulks calculated in this way are compared with those obtained by expressions limited to smaller regions, focusing on accuracy and convergence as function of the self-consistent calculation volume. A faster and variational ͑monotonic͒ convergence is obtained by using the energy expression proposed in this paper.

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Flow Characterization of the UL Smoke Box and Spot-Type Smoke Detectors The certification and testing of fire protection devices can be an expensive and arduous task. Although fire detection as an industry has rapidly evolved over the past quarter Special thanks must also be given to Ms. Erika Echavarria and Mr. Gerald Angle for their prior assistance during the first, experimental phase of the project. Last but certainly not least, are my family and friends. I cannot extend a large enough thank you to my parents who have helped mold me into who I am today. My mother, especially, deserves the most thanks in guiding me on the lesser beaten path of not only leading a budding successful career, but personal one as well. My parents along with my sister and extended family (who are too many to list individually) have all had a genuine hand in supporting me in this venture-be it financially, physically, or emotionally. Without all of their support it is hard to tell where my unguided endeavors would have delivered me. My friends, who were encouraging in their own unique ways, cannot go un-thanked; and if mentioned specifically, egos would surely hang me for leaving one of them out of "print." v