Among the many factors that effect the atomization of a fuel spray in a com- bustion chamber, the flow characteristics of the fuel inside the injector nozzle play significant roles. The enthalpy of the entering fuel can be elevated such that it is higher than the local or downstream saturation enthalpy, which will result in the flash-boiling of the liquid. The phase change process dramatically effects the flow rate and has the potential to cause subsonic two-phase choking. The timescale over which this occurs is comparable to the flow-through time of the nozzle and hence any attempt to model this phenomenon needs to be done as a finite rate process. In the past the Homogeneous Relaxation Model (HRM) has been successfully employed to model the vaporization in one dimension. Here a full three dimensional imple- mentation of the HRM model is presented. Validations have been presented with experiments using water as working fluid. For the external spray modeling, where the fuel is said to be flash boiling, the phase change process plays a role alongside the aerodynamic breakup of the liquid and must be considered for obtaining the fuel spray characteristics. In this study the HRM model is coupled with Linearized Sheet Instability Analysis (LISA) model, for primary atomization, and with Taylor Analogy Breakup (TAB) model for secondary breakup. The aerodynamic breakup model and phase change based breakup model are designed as competing processes. The mechanism which satisfies its breakup criterion first during time integration is used to predict resulting drop sizes.

With the years ahead promising few certainties, limited growth and challenges from every direction to the investment assumptions of old, commercial real estate is taking on new relevance. Both listed and unlisted commercial real estate investments have come of age. This thesis will look at the opportunities which direct property and REITs offer to investors, and consider the wide-ranging contribution the sector makes to society and the entire economy. The dissertation consists of a general introduction and three independent but relevant chapters to deeply analyze the Spanish and the Chinese cross-border real estate investment issues from diversified perspectives. The thesis involves both listed and unlisted real estate questions that are unexplained well in existing literature yet. The general introduction broadly presents a big picture of the globe, the Spanish, and the Chinese real estate investment environments and status, respectively. Also, the research background and significance, as well as the theoretical foundation for this study and methodologies adopted for each chapter are lined out here. Chapter 1 aims to figure out those potential determinants for international capital flow towards the Spanish unlisted real estate and construction sectors. By applying the Stock-adjustment model developed by William H. Branson in 1968, and via the Vector Autoregression (VAR), Vector Error Correction Model (VECM), as well as the Pooled Engle and Granger Least Square (Pooled-EGLS) regression method, the empirical results demonstrated that the Spanish GDP growth rate, the M3 money supply, housing prices, country risk, as well as interest rates have a strong correlation with foreign real estate capital flow towards the Spanish property sector. Besides, cross-border capital flows into the Spanish construction sector is also estimated by utilizing the same indicators for real estate study. But less evidence is found through the same pattern. Chapter 2 focuses on the analyses of risk and returns relationship far the Spanish REITs. The celebrated Fama and French Three-Factor (FF3) model developed by Eugene Fama and Kenneth French in 1993 is applied in this case. Based on the Autoregressive Distributed Lag Model (ARDL), the results indicate that the Spanish REITs yields can be explained well by the Market, Size, and Value three standard Fama-French factors, which are in line with the previous research on common shares. By comparison purposes, the Carhart four factors model that expanded from the FF3 model also employed. However, the momentum indicator is not significant in this case. Chapter 3 analyzes what drivers that likely drive the Chinese real estate capital outflows to the main European cities. This article adopts the Gravity Model of trade to do the research, which has been extensively utilizing far FDI studies. Due to the zero-investment issue that exists during the sample period, the Heckman model is utilized to avoid the sample selection bias. Both Maximum Likelihood and Two-Step regression methods are run but paying attention to the results from the ML method. The first-step regression results indicating that push factors such as China's foreign exchange reserves and the Chinese government investment policy (Belt & Road lnitiative), as well as a set of pull factors including the host cities inflation, real estate transparency, housing prices index, and the total resident population, affecting the probability that China sends its real estate capital to the recipient cities. For the gravity model that corrected by the lnverse Mills Ration, the second-step regression results tell that only the Chinese GDP affects the real estate capital outflows in the destinations in this case.

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The research detailed in this study focuses on the determination of an appropriate objective function to aid parameter estimation when simulating areas influenced by tidally varying flows. Three objective functions that are measures of how well the model results match field data at several locations and times were tested. A set of test cases is developed to represent tidally influenced systems and allow for the testing of the objective functions. These objective functions were tested by computing their values and comparing them for the various estimated parameters. Based on results of the first method of testing a further analysis was performed using PEST, an automatic parameter estimation tool. A weighted least squares of the velocity and water surface values with a weight function on the velocity term based on the shallow water equations is found to be a reasonable objective function at this point in the research.

The laminar flow in the small bronchial tubes is quite complex due to the presence of vortex-dominated, secondary flows. Contributing to this complexity are the geometrical characteristics of the bronchial tubes that include asymmetric and nonplanar branching. These secondary flow fields play a crucial role in particle deposition; however, the actual mechanisms that determine the particle distributions are not fully understood. The research reported here increases understanding of this phenomenon by studying flow structure/ particle interaction in the small bronchial tubes for steady and unsteady respiratory conditions. Specifically, the effects of simultaneous nonplanar and asymmetric branching were investigated. The nonplanar model was generated by applying a 90◦ out-of-plane rotation to the third-generation branches. Steady-state inspiratory flows for a Reynolds number of 1,000 and unsteady periodic flows with a 30-respiration-per-minute breathing frequency were simulated in three-generation, asymmetric, planar and nonplanar models. The asymmetry and nonplanarity produced asymmetric secondary flow patterns and unequal mass flow partitioning in the third-generation branches. Ten micron water droplet deposition in the nonplanar model was found to be significantly different from the planar model, demonstrating the impact of simultaneous nonplanar and asymmetric branching. The unsteady nature of the flow also affected particle deposition. Particles released at the same instantaneous inflow conditions during off-peak inhalation conditions, generated significantly different particle deposition patterns. The differences were attributed to the high temporal variations of the fluid velocities at these off-peak times and history effects in the flows. It was also observed that the initial particle velocities had a significant impact on particle deposition. The study of flow structure and particle interaction was facilitated by the development of a novel visualization technique that employs finite-time Lyapunov exponents (FTLE). This research provides a better understanding of the fluid dynamics driving the particle deposition in the bronchial tubes.

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