The Turbulent Heat Transfer Test Facility (THTTF) has been refurbished and the data acquisition system upgraded. The THTTF is now controlled by a LabView 4.1 program which replaces the old program in BASIC. Heat transfer data acquired using this new program is presented as Stanton number distributions. The new data set is compared to previously reported data obtained with this facility and other wellepted published data. This project has successfully qualified the THTTF for zero-pressure gradient, isothermal wall temperature, incompressible boundary-layer flow over smooth flat plates without transpiration. The THTTF is now set to accommodate modifications which will facilitate heat transfer investigations with high freestream turbulence.

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The flow through a compressor cascade with tip leakage has been studied experimentally. The cascade of GE rotor B section blades had an inlet angle of 65.1º, a stagger angle of 56.9º, and a solidity of 1.08. The final turning angle of the cascade was 11.8º. This compressor configuration was representative of the core compressor of an aircraft engine. The cascade was operated with a tip gap of 1.65%, and operated at a Reynolds number based on the chord length (0.254 m) of 388,000. Measurements were made at 8 axial locations to reveal the structure of the flow as it evolved through the cascade. Measurements were also made to reveal the effects of grid generated turbulence on this flow. The data set is unique in that not only does it give a comparison of elevated free stream turbulence effects, but also documents the developing flow through the blade row of a compressor cascade with tip leakage. Measurements were made at a total of 8 locations 0.8, 0.23 axial chords upstream and 0, 0.27, 0.48, 0.77, 0.98, and 1.26 axial chords downstream of the leading edge of the blade row for both inflow turbulence cases. The measurements revealed the formation and development of the tip leakage vortex within the passage. The tip leakage vortex becomes apparent at approximately X/ca= 0.27 and dominated much of the endwall flow. The tip leakage vortex is characterized by high streamwise velocity deficits, high vorticity and high turbulence kinetic energy levels. The result showed that between 0.77 and 0.98 axial chords downstream of the leading edge, the vortex structure and behavior changes. The effects of grid generated turbulence were also documented. The results revealed significant effects on the flow field. The results showed a 4% decrease in the blade loading and a 20% reduction in the vorticity levels within tip leakage vortex. There was also a shift in the vortex path, showing a shift close to the suction side with grid generated turbulence, indicating the strength of the vortex was decreased. Circulation calculations showed this reduction, and also indicated that the tip leakage vortex increased in size by about 30%. The results revealed that overall, the turbulence kinetic energy levels in the tip leakage vortex were increased, with the most drastic change occurring at X/ca= 0.77. / Ph. D.

With a look towards the future, which involves a push towards utilizing renewable energy sources and cementing energy independence for future generations, the design of more efficient aircraft and novel energy systems is of utmost importance. This dissertation looks at leveraging some of the benefits offered by inflatable wings for use in tethered kite-like systems towards the goal of designing a High Altitude Aerial Platform (HAAP). Uses of such a system include Airborne Wind Energy Systems (AWES), among others. The key bene- fit offered by such wings is their lightweight construction and durability, but challenges to aerodynamic performance arise out of their flexible nature and non-standard airfoil profile. Studying the aerodynamic behavior of such wings forms the critical focus of this research. This effort primarily encompasses an experimental investigation of two swept, tethered, inflatable wings conducted in the Virginia Tech Stability Wind Tunnel, and numerical CFD computations of these wings. The experiment was conducted in the modular wall configuration of the anechoic test section at speeds ranging from 15 − 32.5 m/s for three different tether attachment configurations and wings constructed out of two different fabric materials. Along with static aeroelastic deformation data using a 3D photogrammetry system, aerodynamic measurements were taken in the form of Pitot and static pressure measurements in the wake of the wing, force and moment measurements at the base of the mount, and tension measurements at the tether attachment locations. This provides a data set for validating static aeroelastic modeling approaches for such a system and highlights the dramatic effect of the variability in test configuration on the wing's aerodynamics. In addition to the wind tunnel tests, 3D steady RANS CFD computations of the rigid 3D scanned inflatable wing geometry were conducted in the wind tunnel environment for these configurations to validate the CFD modeling approach and highlight the level of detail necessary to accurately characterize the wing aerodynamic performance. Static aeroelastic deformation data from the 3D photogrammetry system, at a speed of 27.5 m/s, were also used to deform the 3D scanned inflatable wing geometry, and RANS CFD computations of this deformed inflatable wing were conducted at a wind tunnel speed of 27.5 m/s. Several turbulence models were investigated and comparisons were made with the wind tunnel test data. Good agreement was found with experimental data for the forces and moments and wake Pitot pressure coefficient contours. Comparisons were also made with the rigid wing CFD computations at the same tunnel speed of 27.5 m/s to illustrate the effect of static aeroelastic deformations on the aerodynamic performance, wake Pitot pressure coefficient contours and wing-tip vortex structures, of these flexible inflated wings. In effect, this research utilizes the synergy be- tween wind tunnel experiments and numerical CFD computations to study the flow behavior over inflatable wings and provide a comprehensive verification and validation approach for modeling such complex systems. / Doctor of Philosophy / With a look towards the future, which involves a push towards utilizing renewable energy sources and cementing energy independence for future generations, the design of more efficient aircraft and novel energy systems is of utmost importance. This dissertation looks at leveraging some of the benefits offered by inflatable wings for use in tethered kite-like systems towards the goal of designing a High Altitude Aerial Platform (HAAP). Uses of such a system include Airborne Wind Energy Systems (AWES), among others. The key benefit offered by such wings is their lightweight construction and durability, but challenges to aerodynamic performance arise out of their flexible nature and non-standard airfoil profile. Studying the aerodynamic behavior of such wings forms the critical focus of this research. This effort primarily encompasses an experimental investigation of two swept, tethered, inflatable wings conducted in the Virginia Tech Stability Wind Tunnel, and computer simulations of the aerodynamic flow over these wings. The experiment was conducted in the modular wall configuration of the anechoic test section at speeds ranging from 15 − 32.5 m/s for three different tether attachment configurations and wings constructed out of two different fabric materials. Along with measurements of the wing deformations using a 3D photogrammetry system, aerodynamic measurements were taken in the form of pressure measurements in the wake of the wing, force and moment measurements at the base of the mount, and tension measurements at the tether attachment locations. This provides a data set for validating static aeroelastic modeling approaches for such a system and highlights the dramatic effect of the variability in test configuration on the wing's aerodynamics. In addition to the wind tunnel tests, detailed computer simulations of the scanned inflatable wing geometry were conducted in the wind tunnel environment for these configurations to validate the computational modeling approach and highlight the level of detail necessary to accurately characterize the wing aerodynamic performance. The wing deformation data from the 3D photogrammetry system, at a speed of 27.5 m/s, were also used to deform the scanned inflatable wing geometry, and computer simulations of this deformed inflatable wing geometry were conducted at a wind tunnel speed of 27.5 m/s. Good agreement was found between the experimental and computational forces and moments and wake Pitot pressure coefficient contours. Comparisons were also made with the undeformed wing computations at the same tunnel speed of 27.5 m/s to illustrate the effect of wing flexibility on the aerodynamic performance. In effect, this research utilizes the synergy between wind tunnel experiments and numerical CFD computations to study the flow behavior over inflatable wings and provide a comprehensive verification and validation approach for modeling such complex systems.

To solve traffic congestion in Bangkok, the Bangkok Mass Transit system (BTS) constructed an overhead rail system with 24 stations. The BTS train station, S2, in this study area covers Silom road and obstructs the air pollutant dispersion in a congestion area. The 1: 200 physical model of the buildings along Silom road with the train station, S2, was simulated in this research to determine the air pollutant dispersion in the train station area. A tracer gas (CO₂) was emitted from a simulated line source with emission rates of 0.383, 0.681, 1.293, 2.586, 5.177 and 10.77 mg/min to simulate actual pollutant emission rates. The CO₂ gas was sampled at 55 locations in the model. The Kriging method was used to interpolate the data in the study area. . Emission rates were used to make the difference between measured CO₂ in the model area and ambient CO₂ large enough to be differentiated. Regression Analysis was used to relate analytically the mass emission rate to the CO₂ concentration. The results indicate that the maximum CO concentrations exceed the 30 ppm Bangkok standard along the Southeast side of Silom Road at the passenger platform level. Drivers will acquire more harmful levels of CO than pedestrians at street level, especially near the Southwest end of the train station. NO₂ concentrations do not exceed the standard (0.17 ppm) at street level. The highest predicted VOC is 1.05 ppm. These results may be used in the future for numerical modeling study. / Master of Science

A supersonic wind tunnel, with a 20" x 20'" test section cross sectional area, was designed and constructed at the Techsburg Wind Tunnel Facility in order to determine the lift and drag on irregularly shaped fragments in supersonic flow. Prior to beginning the wind tunnel design process, a blowdown analysis model was created in order to determine the influence of a number of parameters on tunnel run time and test gas properties throughout the tunnel circuit. The design of the settling chamber, test section, supersonic nozzles, diffuser, and exhaust are presented in this thesis. Diffuser performance has a large influence on wind tunnel efficiency and run time. Therefore, significant efforts should be taken in order to attain the highest possible pressure recovery within the diffuser. The design of wind tunnel components, as well as their stress analysis, was conducted using SolidWorks. The control valve and silencer were sized and selected for the expected tunnel operating conditions. Since the control valve tends to encompass a significant portion of the overall tunnel cost, care must be taken to ensure it has a large enough flow capacity to produce the desired test conditions. Also, attempts must be made to accurately predict the total pressure loss through the silencer, since this loss can have a large impact on the total pressure ratio necessary to produce the design Mach number. Upon completion of the design process, the supersonic wind tunnel was assembled, and shakedown testing was conducted. During shakedown testing it was determined that the wind tunnel was capable of producing Mach 2 flow in the test section. Following shakedown testing, a flow survey was conducted in order to ensure uniform Mach number flow exists throughout the region occupied by the fragments. Based on the flow survey it was determined that within the middle 60% of the test section, the average Mach number was 1.950 and varied by only 0.56% within this region. Two irregularly shaped fragments were tested at Mach 2 flow, over an effective 360° pitch sweep, with wind tunnel runs performed every 10 degrees. Based on the measured force data for both fragments, the lift appeared to follow a sinusoidal curve, with minimum values at 0, 90, and 180° balance pitch angle, and maximum values occurring around 45 and 135° pitch angle. The drag force was observed to follow a gradual curve with minimum values at 0 and 180° balance pitch angle, as expected since the fragment presented area is generally least in this orientation. The maximum drag was found to occur at a balance pitch angle of 90°, once again as expected since the fragment presented area is generally greatest at this angle. It was also observed that the fragment drag tended to be greater for a fragment orientation which places the concave side of the fragment into the direction of the flow. / Master of Science

This project studied the effects of wind tunnel test loads applied to purlins in low rise steel buildings compared to those determined with currently recognized wind loading provisions. The National Institute of Standards and Technology (NIST) database of low-rise building wind tunnel test data, which was collected at the University of Western Ontario (UWO) boundary layer wind tunnel, was used to model a realistic wind load scenario. Pressure coefficient data recorded in the database was applied statically to individual purlins in a typical design for the size of buildings studied. These results were then compared to those obtained using the wind design provisions in ASCE 7-16 Chapter 30 for Components and Cladding. The primary data of interest was shear and moment values along the length of the purlins, which were modeled as continuous beams. Comparisons were made between the resultant shear and moment from both the wind tunnel load and ASCE 7-16 load values at 1-foot increments along the length of the purlin. The results showed that the overall peak values obtained from wind tunnel test loads were 3% to 49% higher than those calculated using ASCE 7-16 for purlins that were on the windward edge of the building. Purlins on the interior of the building varied in whether they exceeded the loads calculated with ASCE 7. Changing the height of the structure and the terrain roughness both increased the number of purlins that were lower than the values provided in ASCE 7-16 in the interior of the structure. / Master of Science / Purlins are roof members used in low rise steel buildings to transmit wind loads applied to the roof of the structure to the frame of the building. This project studied the effects of applying loads to purlins using methods specified by the code compared to those found in a wind tunnel, to look at the similarity of the values and model the actual behavior of the purlins more accurately. For this study, wind tunnel test data obtained from the National Institute of Standards and Technology (NIST) database was applied to the purlins and the shear and moment was calculated. These results were compared to the current code requirements provided in the American Society of Civil Engineers (ASCE) 7 document: Minimum Design Loads and Associated Criteria for Buildings and Other Structures. The results showed that the loads developed in the purlins subjected to wind tunnel test loadings were 3% to 49% higher on the edge of the building than those that had the ASCE 7 design loads applied. More accurately modeling the behavior of the purlins using wind tunnel test data and beam models showed that in locations where the purlins received the maximum wind force, the ASCE 7 requirements for components and cladding tended to be lower than the wind tunnel test data. However, in locations where the purlins were not experiencing the maximum wind force, the ASCE 7 requirements tended to overpredict the loads, based on the use of symmetric high wind areas to design for all wind angles.

Morphing aircraft combine both radical and subtle wing shape changes to improve vehicle performance relative to a rigid airframe. An aircraft wind tunnel model with considerable wing-shape freedom can serve as a tool in learning to model, control, and fully exploit the potential of such vehicles. This work describes the design, development, and initial analysis of a wind tunnel model that combines large and small wing shape variations for fundamental research in modeling and control of morphing air vehicles. The vehicle is designed for five primary purposes: quasi-steady aerodynamic modeling of an aircraft with large planform changes, optimization studies in achieving efficient flight configurations, transient aerodynamic modeling of high-rate planform changes, evaluating planform maneuvering as an control effector, and gimbaled flight control simulation of a morphing aircraft. The knowledge gained from the wind tunnel evaluations will be used to develop general stabilization and optimal control strategies that can be applied to other vehicles with large scale planform changes and morphing flight models. After a brief background on the development of the Morphing Aircraft Program, and previous research ventures, the first phase vehicle development is described. The vehicle function, subsystems, and control are all presented in addition to the results of first phase wind tunnel testing. Deficiencies in the phase one design motivated the phase two development which has led to the current vehicle model: MORPHEUS. The evolution towards the MORPHEUS configuration is presented in detail along with an elementary strength analysis. The new embedded control implementation to permit a rate controllable planform is included. A preliminary aerodynamic analysis is presented to contrast MORPHEUS against the phase one design and an industry morphing concept. In particular, it is shown how the redesigned model has enhanced performance characteristics and the additional degrees of freedom enable greater flexibility in optimizing a configuration, especially with respect to trim characteristics. An expansion of traditional analysis techniques is applied to derive a new optimal twist algorithm for the MORPHEUS model at each planform configuration. The analysis concludes with a hybrid continuous modeling method that combines first-order computational aerodynamic modeling with classic stability expressions and DATCOM enhancements. The elementary aerodynamic coefficients are computed over the range of possible planform configurations and combined with the optimal twist results for preliminary trim analysis. This work precedes phase two wind tunnel testing and transient modeling. Future work involves expansion into the five purposes detailed for the MORPHEUS model. / Master of Science

Using Computational Fluid Dynamics Simulations, the flow in the new University of Sydney closed circuit wind tunnel has been analyzed prior to the construction of the tunnel. The objective was to obtain a uniform flow in the test section of the wind tunnel while keeping the pressure losses over the tunnel as low as possible. This was achieved by using several flow-improving components such as guide vanes, screens, a honeycomb and a settling chamber. The guide vanes were used in the corners and in the diverging part leading into the settling chamber, giving a significant improvement of the flow as they prevent it from taking undesired paths. The settling chamber is used to decelerate the flow before it is accelerated when leaving the settling chamber, a process which reduces the turbulence in the flow. Screens were used in the settling chamber to further improve the flow by imposing a pressure drop which evens out differences in the flow speed and reduces the turbulence. The honeycomb, which is situated in the end of the settling chamber, makes the flow more uniform by forcing it to go in only one direction. A uniform flow was obtained using three screens and one honeycomb together with the guide vanes and the settling chamber.

The use of infrared thermography for boundary layer detection was evaluated for use in the Cal Poly Low Speed Wind Tunnel (LSWT) and recommendations for the successful use of this technique were developed. In cooperation with Joby Aviation, an infinite wing model was designed, manufactured and tested for use in the LSWT. The wing was designed around a custom airfoil profile specific for this project, where the nearly-flat pressure gradient at a zero pitch angle would delay the chordwise onset of boundary layer transition. Steady-state, RANS numerical simulations predicted the onset of transition to occur at 0.75 x/c for the design Reynolds Number condition of 6.25x105. The wing was manufactured from 3D printed aluminum, with a wall thickness of 0.125 inches and a chord length of 13.78 inches. Two central rows of static pressure taps were used, each with 12 functional chordwise locations. The taps were able to generate strong correlation to the numerically predicted pressure coefficient distribution. The use of an infrared camera visualized and confirmed the presence of boundary layer transition at the chordline location anticipated by the early simulations. To do so, the model was pre-heated such that the differential cooling properties of laminar and turbulent flow would generate a clear temperature gradient on the surface correlating to boundary layer transition. Adjustment of the model’s pitch angle demonstrated a change in the onset location of boundary layer transition during the infrared testing. The change of onset location was seen to move forward along the chordline as the aerodynamic angle of attack was increased. Testing with a Preston Tube system allowed for the interpolation of local skin friction coefficient values at each static tap location. Application of both laminar and turbulent empirical assumptions, when compared to numerical expectations, allowed for the qualitative assessment of boundary layer transition onset. Overall, the wing model developed for this research proved capable of producing quality and repetitive results for the experimental goals it was designed to meet. The model will next be used in continued tests which will further explore the use of infrared thermography.