In this work, reconstruction techniques for the spatial interpolation and extrapolation of sound fields in urban environments are presented. Gaussian processes are generally used for sound field reconstruction from limitedly observations of isotropic acoustic fields. However, this model is often not applicable for the anisotropic urban environments including urban street canyons and enclosed spaces, when the complexity of the sound field is high in the mid-frequency regime, unless diffusely reflecting boundaries are assumed. Two different techniques are compared for reconstructing the sound field: the least-squared method and the Kirchhoff-Helmholtz integral equation method. Of particular interest is the reconstruction of the sound field with a minimal number of irregularly and arbitrarily distributed microphone measurements. Therefore, the techniques will not require knowledge of the microphone positions. A successive series approximation approach is presented to enhance the microscale prediction of the Kirchhoff-Helmholtz integral equation method. The sound field reconstruction results from limited urban environment observations for both methods are presented and discussed.

Geothermal heat pumps present a very intricate installation process and requires a vast amount of space which can cause a financial hurdle for most users. The geothermal system makes use of the constant ground temperature at the minimum of 5 ft depth with a thermal conductive working fluid and specified length of pipping. The system undergoes the necessary heat transfer that will be used as part of the heating or cooling process. In this study, an additively manufactured heat exchanger was designed and developed to address this issue. The design has an innovative coiled inner pipping to reduce the space needed for its installation, as well as combining the heat exchanger component with a drill bit design to simplify and reduce the cost of installation. We used CREO 8.0 to make a detailed drawing and CAD model of the system, which will then be simulated on ANSYS fluent software. During the simulation we studied the performance of heat transfer. In addition, this study also analyzes the coefficient of heat transfer and fluid pressure drop as a function of Reynolds number. For production of the system an additive manufacturing technique was used to manufacture the prototype.

In this work, the localization and tracking of acoustic sources in an urban environment is presented. Of particular interest is the performance of mobile acoustic sensors. In real world situations, sources are moving making it difficult to track their location especially in changing environments. The performance of mobile acoustic sensors is investigated. Beamforming and TDOA based techniques will be employed in various non-line of sight scenarios. The results and limitation of these techniques both numerically and experimentally will be discussed.

In this work, techniques for localizing impulsive acoustic sources in an urban environment are presented. Of particular interest is the localization of sources in urban street canyons and enclosed urban areas. Sound propagation in an urban environment is strongly influenced by multiple reflections. In urban street canyons, multiple reflections tend to amplify with decreasing canyon width. A numerical investigation is performed to study the role multiple reflections on time difference of arrival (TDOA) and beamforming source localization techniques. Results of various urban street canyon and enclosed space geometries are investigated. The results and limitations of the TDOA and beamforming techniques for estimating source position in urban environments are discussed.

In this work, the influence of micrometeorological effects on sound propagation in an urban street canyon is investigated numerically and experimentally. Numerical simulations of acoustic propagation are based on sound particle propagation simulation method. Numerical data are generated for urban street canyons of various widths and height ratios. Experimental data are obtained from longitudinal measurements of urban street canyons in the United States. Temperature and wind profiles are obtained from ultrasonic anemometers and thermocouples. Measurements within and outside the street canyon are of particular interest. The experimental data are useful in integrating micrometeorological effects into the acoustic propagation model. Preliminary numerical results and measurements are presented and discussed.