Browsing by Subject "Isotropy"
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Item Determination of the proper site spacing density over Texas(2005-08) Sonmez, Ibrahim; Schroeder, John L.; Peterson, Richard E.; Smith, Douglas A.The current meteorological surface observation network in Texas only monitors one out of every five counties. The observation sites are nominally spaced 150-200 km apart and report hourly measurements. For this reason, the current system is incapable of providing observations at a spatial and temporal resolution to document mesoscale weather features and provide short-range forecasting. To overcome this problem, various site spacing procedures are used to propose to fill the gaps in the monitoring system. In this study, site spacing determination procedures based on correlation level, power spectrum, and true field error variance are used to analyze the temperature, dew point temperature, wind speed and pressure parameters over Texas. Hourly observations from 126 surface observing sites located in Texas and the adjacent states with a data coverage period varying from 6 to 21 years are considered for the study. The existence of isotropic conditions over the domain is tested by examining the spatial correlation variations of the parameters. The existence of anisotropic conditions for each parameter resulted in the search for sub-regions within the domain. Cluster analysis indicated three separate clusters for the domain. For each cluster, the spatial correlation variations are examined and spectral analysis is applied to determine the governing scales for each parameter’s variation. Error amounts in obtaining the true Fourier coefficients are analyzed; the highest wave number that can reasonably estimated is determined for each parameter in each cluster. Finally, the error variance in determining the true field for each parameter is examined for site spacings of 200, 150, 100, 50, and 25 km for each cluster.Item Determination of the proper site spacing density over Texas(Texas Tech University, 2005-08) Sonmez, Ibrahim; Schroeder, John L.; Peterson, Richard E.; Smith, Douglas A.The current meteorological surface observation network in Texas only monitors one out of every five counties. The observation sites are nominally spaced 150-200 km apart and report hourly measurements. For this reason, the current system is incapable of providing observations at a spatial and temporal resolution to document mesoscale weather features and provide short-range forecasting. To overcome this problem, various site spacing procedures are used to propose to fill the gaps in the monitoring system. In this study, site spacing determination procedures based on correlation level, power spectrum, and true field error variance are used to analyze the temperature, dew point temperature, wind speed and pressure parameters over Texas. Hourly observations from 126 surface observing sites located in Texas and the adjacent states with a data coverage period varying from 6 to 21 years are considered for the study. The existence of isotropic conditions over the domain is tested by examining the spatial correlation variations of the parameters. The existence of anisotropic conditions for each parameter resulted in the search for sub-regions within the domain. Cluster analysis indicated three separate clusters for the domain. For each cluster, the spatial correlation variations are examined and spectral analysis is applied to determine the governing scales for each parameter’s variation. Error amounts in obtaining the true Fourier coefficients are analyzed; the highest wave number that can reasonably estimated is determined for each parameter in each cluster. Finally, the error variance in determining the true field for each parameter is examined for site spacings of 200, 150, 100, 50, and 25 km for each cluster.Item Experimental investigation of the performance of a fully cooled gas turbine vane with and without mainstream flow and experimental analysis supporting the redesign of a wind tunnel test section(2013-12) Mosberg, Noah Avram; Bogard, David G.This study focused on experimentally determining the cooling performance of a fully cooled, scaled-up model of a C3X turbine vane. The primary objective was to determine the differences in overall effectiveness in the presence and absence of a hot mainstream flowing over the vane. Overall effectiveness was measured using a thermally scaled matched Biot number vane with an impingement plate providing the internal cooling. This is the first study focused on investigating the effect of removing the mainstream flow and comparing the contour and laterally-averaged effectiveness data in support of the development of an assembly line thermal testing method. It was found that the proposed method of factory floor testing of turbine component cooling performance did not provide comparable information to traditional overall effectiveness test methods. A second experiment was performed in which the effect of altering the angle of attack of a flow into a passive turbulence generator was investigated. Measurements in the approach flow were taken using a single wire hot-wire anemometer. This study was the first to investigate the effects such a setup would have on fluctuating flow quantitates such as turbulence intensity and integral length scale rather than simply the mean quantities. It was found that both the downstream turbulence intensity and the turbulence integral length scale increase monotonically with approach flow incidence angle at a specified distance downstream of the turbulence generator.