Wind resource assessment at California Polytechnic State University shows there is potential for wind power generation on Cal Poly land. A computational fluid dynamics model based on wind data collected from a campus maintained meteorological tower on Escuela Ranch approximately 5 miles northwest of campus suggests there are areas of Cal Poly land with an IEC Class III wind resource at a height of 80 meters above ground. In addition during the daytime when the campus uses the most energy there are large portions of land with annual average daytime wind speeds above 6.9m/s. These areas have been identified by analyzing the wind speed and directional data collected at the meteorological tower and using it to create the boundary conditions and turbulence parameters for the computer model. The model boundary conditions and turbulence parameters have been verified through comparison between data collected at Askervein hill in Scotland during the 1980’s and the results of a simulation of Askervein hill using the same model. Before constructing a wind farm for power generation, additional meteorological towers should be constructed in Poly Canyon to further confirm the wind resource prediction.

A numerical investigation on the combustion mechanics of a hybrid rocket engine is performed through unsteady Reynolds-averaged Navier-Stokes simulation. The hybrid rocket engine model is based on an experimental laboratory scale engine design operating on GOX and HDPE as a propellant. A simple convection heat flux model is used to determine the heat transfer to the fuel wall. The project is done with the goal of finding the fuel regression rate in mind, as it is an essential parameter for determining engine performance. The results show early results of the fluid- and thermodynamics occurring in the combustion chamber. Propellant mixing is shown to not be optimal as a significant part of the exit flow consists of high concentrations of oxidizer that has not reacted with the fuel. The flame temperature is shown to be relatively high inside the combustion chamber. It is concluded from the simulations that the model needs further improvement in order to accurately compute the flow as well as the heat transfer to the fuel. To determine the regression rate, radiation should be implemented into the heat transfer model.

Liquid Storage Tanks (LSTs) are essential infrastructure systems that are used in various municipal and industrial settings. They play a critical role in storing and transporting liquids such as drinking water, oil, and gas that are used in daily life. Failure of these structures due to their poor seismic performance can have devastating consequences including the release of the stored liquid and damage to the surrounding area with potentially irreversible environmental impacts. In addition, the damage caused to the tank structure can be extensive, resulting in significant financial losses. Furthermore, the disruption of services provided by the tank such as water supply, oil and gas storage can be considerable. It is therefore crucial to study the seismic behaviour of these structures and ensure their safety and reliability to minimize the potential damages. The aim of this study is to investigate the behavior of LSTs in terms of the contained liquid, the tank’s structure, and its supports when subjected to seismic excitations. To obtain accurate results, different numerical techniques are applied in different phases of the study, including the Finite Volume Method (FVM), Finite Elements Method (FEM), Volume of Fluids (VoF) method, and Smoothed Particles Hydrodynamic (SPH) method. These techniques allow for a detailed analysis of the behavior of the tank and its supports during seismic excitation, providing a comprehensive understanding of the performance of LSTs during earthquakes. In order to examine the reliability and accuracy of the numerical model, the first part of the study includes the validation of the developed numerical model through comparison of the model and experimental results. The validated numerical model is then used to obtain the hydrodynamic pressures at different locations on the roof of tanks subjected to base excitations. The effect of liquid impact and hydrodynamic pressures on the roof of LSTs can be significant, however, limited studies have been completed on this issue. In the second part of the study, Artificial Intelligence (AI) techniques such as Genetic Programming are used to formulate these pressure values so that the maximum pressure can be obtained using the tank characteristics such as size and fill depth by the relationship obtained based on the AI approach. In the third part of the study, the supporting structures of LSTs subjected to base excitations are analyzed, and their shear forces are extracted and compared with the National Building Code of Canada (NBC 2020) in order to evaluate the reliability of the code and discuss possible improvements. The results of this study can be used to evaluate and make improvements in standards and guidelines for the seismic design of LSTs, which can help ensure the safety and reliability of these crucial infrastructures during seismic events.

A numerical method for modeling a low Reynolds number turbine blade, the L1M, is presented along with the pitfalls encountered. A laminar solution was confirmed to not accurately predict the flow features known in low Reynolds number turbine blade flow. Three fully turbulent models were then used to try to predict the separation and reattachment of the flow. These models were also found to be insufficient for transitioning flows. A domain was created to manually trip the laminar flow to turbulent flow using a predictive turbulence transition model. The trip in the domain introduced an instability in the flow field that appears to be dependent on the discretization order, turbulence model, and transition location. The method was repeated using the Pack B blade and the same obstacles were apparent. The numerical method developed was then used in an optimization technique developed to design a wind tunnel simulating periodic flow conditions using only 2 blades. The method was first used to predict a c_p distribution for the aft loaded L1A research blade provided by the U.S. Air Force. The method was then extended to a larger domain emulating the 2 blade, 2D wind tunnel. The end-wall geometry of the tunnel was then changed using previously defined control points to alter the distribution of c_p along the suction surface of the interior blades. The tunnel c_p's were compared to the computationally acquired periodic solution. The processed was repeated until an acceptable threshold was reached. The optimization was performed using the commercially available software iSIGHT by Engineous Solutions. The optimization algorithms used were the gradient based Successive Approximation Method, the Hooke Jeeves, and Simulated Annealing.

Presented here is a novel tool to extract and track believable vortex core lines from unsteady Computational Fluid Dynamics data sets using multiple feature extraction algorithms. Existing work explored the possibility of extracting features concurrent with a running simulation using intelligent software agents, combining multiple algorithms' capabilities using subjective logic. This work modifies the steady-state approach to work with unsteady fluid dynamics and is designed to work within the Concurrent Agent-enabled Feature Extraction concept. Each agent's belief tuple is quantified using a predefined set of information. The information and functions necessary to set each component in each agent's belief tuple is given along with an explanation of the methods for setting the components. This method is applied to the analyses of flow in a lid-driven cavity and flow around a cylinder, which highlight strengths and weaknesses of the chosen algorithms and the potential for subjective logic to aid in understanding the resulting features. Feature tracking is successfully applied and is observed to have a significant impact on the opinion of the vortex core lines. In the lid-driven cavity data set, unsteady feature extraction modifications are shown to impact feature extraction results with moving vortex core lines. The Sujudi-Haimes algorithm is shown to be more believable when extracting the main vortex core lines of the cavity simulation while the Roth-Peikert algorithm succeeding in extracting the weaker vortex cores in the same simulation. Mesh type and time step is shown to have a significant effect on the method. In the curved wake of the cylinder data set, the Roth-Peikert algorithm more reliably detects vortex core lines which exist for a significant amount of time. the method was finally applied to a massive wind turbine simulation, where the importance of performing feature extraction in parallel is shown. The use of multiple extraction algorithms with subjective logic and feature tracking helps determine the expected probability that an extracted vortex core is believable. This approach may be applied to massive data sets which will greatly reduce analysis time and data size and will aid in a greater understanding of complex fluid flows.

Heart disease is the main cause of death today, and studying causes and treatments are of great interest. Blood flow simulations using computational fluid dynamics shows promise in providing insight into this area. This study builds upon previous work by Larsson et al. and Kronborg et al. who have developed a program for simulating the blood flow through patient specific left ventricles. More specifically we aimed to improve the accuracy of their blood flow simulation by accounting for the protruding structure of the endocardial wall, previously disregarded in the model due to the limitations in spacial accuracy of echocardiography. These structures, consisting of trabeculae carneae and papillary muscles, have been shown to have a significant impact on the blood flow. In a recent study, Sacco et al. proposed a solution were a porous layer could mimic the effects on the blood flow from these structures in a rigid heart model. Our study aimed to apply this modification to the left ventricle of the dynamic model using the Navier-Stokes-Brinkman flow equation and a subdomain defining the porous region. This study has been working towards the end goal of fully implementing the porous layer into the heart simulation. The equations needed have been formulated and simulations have been run on flow in a more simple setting to verify the model. The simulations show promise in being able to recreate the results from Sacco et al. but further development is needed before the porous model can be tested in the dynamic left ventricle model, most notably defining the porous subdomain in the dynamic model. We conclude that the porous domain will affect the flow, possibly breaking up vortices and reducing the wall shear stress. Confirming this requires additional studies, but the implementation of a porous domain would likely result in a more accurate simulation.

This thesis describes the numerical predictions of turbine film cooling interactions using Large Eddy Simulations. In most engineering industrial applications, the Reynolds-Averaged Navier-Stokes equations, usually paired with two-equation models such as k-Greek lowercase letter epsilon] or k-Greek lowercase letter omega], are utilized as an inexpensive method for modeling complex turbulent flows. By resolving the larger, more influential scale of turbulent eddies, the Large Eddy Simulation has been shown to yield a significant increase in accuracy over traditional two-equation RANS models for many engineering flows. In addition, Large Eddy Simulations provide insight into the unsteady characteristics and coherent vortex structures of turbulent flows. Discrete hole film cooling is a jet-in-cross-flow phenomenon, which is known to produce complex turbulent interactions and vortex structures. For this reason, the present study investigates the influence of these jet-crossflow interactions in a time-resolved unsteady simulation. Because of the broad spectrum of length scales present in moderate and high Reynolds number flows, such as the present topic, the high computational cost of Direct Numerical Simulation was excluded from possibility.

No description available.

Film cooling is a method used to protect surfaces exposed to high-temperature flows such as those that exist in gas turbines. It involves the injection of secondary fluid (at a lower temperature than that of the main flow) that covers the surface to be protected. This injection is through holes that can have various shapes; simple shapes such as those with a straight circular (by drilling) or straight square (by EDM) cross-section are relatively easy and inexpensive to create. Immediately downstream of the exit of a film cooling hole, a so-called horseshoe vortex structure consisting of a pair of counter-rotating vortices is formed. This vortex formation has an effect on the distribution of film coolant over the surface being protected. The fluid dynamics of these vortices is dependent upon the shape of the film cooling holes, and therefore so is the film coolant coverage which determines the film cooling effectiveness distribution and also has an effect on the heat transfer coefficient distribution. Differences in horseshoe vortex structures and in resultant effectiveness distributions are shown for circular and square hole cases for blowing ratios of 0.33, 0.50, 0.67, 1.00, and 1.33. The film cooling effectiveness values obtained are compared with experimental and computational data of Yuen and Martinez-Botas (2003a) and Walters and Leylek (1997). It was found that in the main flow portion of the domain immediately downstream of the cooling hole exit, there is greater lateral separation between the vortices in the horseshoe vortex pair for the case of the square hole. This was found to result in the square hole providing greater centerline film cooling effectiveness immediately downstream of the hole and better lateral film coolant coverage far downstream of the hole.

Advancement in turbine technology has far reaching effects on today's society and environment. With more than 90% of electricity and 100% of commercial air transport being produced by the usage of gas turbine, any advancement in turbine technology can have an impact on fuel used, pollutants and carbon dioxide emitted to the environment. Within the turbine engine, fully understanding film cooling is critical to reliability of a turbine engine. Film cooling is an efficient way to protect the engine surface from the extremely hot incoming gas, which is at a temperature much higher than allowable temperature of even the most advanced super alloy used in turbine. Film cooling performance is affected by many factors: geometrical factors and as well as flow conditions. In most of the film cooling literature, film effectiveness has been used as criterion to judge and/or compare between film cooling designs. Film uniformity is also a critical factor, since it determines how well the coolant spread out downstream to protect the hot-gas-path surface of a gas turbine engine. Even after consideration of all geometrical factors and flow conditions, the film effectiveness is still affected by the stator-rotor interaction, in particular by the moving wakes produced by upstream airfoils. A complete analysis of end wall film cooling inside turbine is required to fully understand the phenomena. This full analysis is almost impossible in the academic arena. Therefore, a simplified but critical experimental rig and computational fluid model were designed to capture the effect of wake on film cooling inside an annular test section. The moving wakes are created by rotating a wheel iv with 12 spokes or rods with a variable speed motor. Thus changing the motor speed will alter the wake passing frequency. This design is an advancement over most previous studies in rectangular duct, which cannot simulate wakes in an annular passage as in an engine. This rig also includes film injection that allows study of impact of moving wakes on film cooling. This wake is a simplified representation of the trailing edge created by an upstream airfoil. An annulus with 30° pitch test section is considered in this study. This experimental rig is based on an existing flat plate film cooling (BFC) rig that has been validated in the past. Measurement of velocity profiles within the moving wake downstream from the wake generator is used to validate the CFD rotating wake model. The open literature on film cooling and past experiments performed in the laboratory validated the CFD film cooling model. With these validations completed, the full CFD model predicts the wake and film cooling interaction. Nine CFD cases were considered by varying the film cooling blowing ratio and the wake Strouhal number. The results indicated that wakes highly enhance film cooling effectiveness near film cooling holes and degrades the film blanket downstream of the film injection, at the moment of wake passing. However, the time-averaged film cooling effectiveness is more or less the same with or without wake