Browsing by Subject "Flow"
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Item A statistical model for estimating mean annual and mean monthly flows at ungaged locations(Texas A&M University, 2004-09-30) Sukheswalla, Zubin RohintonPrediction of flow is necessary for planning and management of water resources. The objective of this study is to estimate mean annual flows for the USA and mean monthly flows for the rivers of central Texas based on the precipitation and their watershed characteristics. Flow varies largely with topographic and climatic parameters and hence generalization of runoff models is difficult. This model aims at providing a prediction at ungaged locations with very few parameters that are easily available and measurable. Scatter in predicted data will be seen at the annual and monthly time scale in the range selected for each data. This model will work on annual and monthly means to reduce the scatter and produce better estimates.Item Can organizational communication strategies that activate associations with mindfulness and flow enhance novel-idea production in an open-ended problem-solving task?(2015-12) Moode, Michael Stephen; Ballard, Dawna I.; McGlone, Matt; Browning, Larry; Treem, Jeffrey; Cox, StephenCreativity is the production of solutions to problems that are both original and appropriate. Although organizational communication literature offers insights regarding overt strategies for enhancing creativity at work (e.g., brainstorming rules), processes whereby creativity may be tacitly enhanced remain largely under-explored. Drawing upon creativity’s associations with heightened awareness (i.e., mindfulness) and the experience of flow—a psychological state characterized partially by distorted perceptions of the passage of time—the present study considers whether exposure to phrases related to these concepts influence the likelihood of one producing more novel ideas in an open-ended problem-solving task. The pursuit of new, tacit means for enhancing the originality of solutions to problems may benefit organizational communication practitioners in the following way. The creativity of employees may be facilitated if new tacit means are used (or avoided) alongside extant overt strategies. Employees may be more capable of producing novel ideas in response to a problem-solving task if organizational communication practitioners develop a more nuanced understanding of how the presentation of problems, and the methods used in solving them, exposes employees to incidental and unobtrusive meanings that shape the socio-environmental context in which problem-solving takes place. The present study used a two-by-two, between subjects factorial design, that presented participants with a set of phrases related to different levels of mindset (i.e., mindfulness and mindlessness) and psychological state (i.e., flow and anti-flow). For example, phrases representing the combination of mindfulness and flow included, “I’m focused,” “my goals are clear,” “I’m tuned in to my feelings,” and “I’m up to the challenge at hand.” Exposure to these phrases sought to activate associations with the mindset of actively and fluidly processing social information (i.e., mindfulness) and the psychological state whereby deep concentration leads to the reduction of self-awareness and awareness of the passage of time (i.e., flow). Conversely, phrases representing the combination of mindlessness and anti-flow included, “I’m not focused,” “my goals are not clear,” “I’m not tuned in to my feelings,” and I’m not up to the challenge at hand.” After being exposed to one of four sets of phrases, participants were then administered a novel-idea production task in which they were instructed to produce a list of solutions to a problem (i.e., people driving while using text messaging on their cell phones). Results of the experiment failed to demonstrate a relationship between the presentation of phrases aiming to trigger associations with mindset and psychological state; however, measures to assess internal reliability suggested that methodological limitations confounded the present study’s ability to accurately test how the activation of associations between mindset and psychological state are related to the likelihood of one producing novel ideas. As such, the present study concludes by drawing a number of insights regarding methodological considerations for future investigations. Specifically, recommendations are drawn regarding participant selection, the research milieu in which novel-idea production may be empirically observed, how associations with different mindsets and psychological states may be primed, and how a problem should be presented within an experiment intending to measure novel-idea production. Summarily, the present study represents a valuable starting point for investigators seeking to contribute to an under-explored topic within the organizational communication literature; for explorations of how the implementation of overt strategies to enhance novel-idea production in organizations may be enhanced by practitioners’ attention to whether and how employees are exposed to stimuli which may prime associations with peak creativity.Item Construction of a diagenetic history and identification with quality ranking of reservoir flow units: Grayson field, Columbia County, Arkansas(Texas A&M University, 2007-04-25) Poole, Kathleen ReneeThe purpose of this study was to describe depositional and diagenetic characteristics of the (Jurassic) Smackover formation and subsequently identify and rank the quality of flow units within Grayson field, Columbia County, Arkansas. The field has production from the Smackover, a reservoir which consists mainly of highly altered peloidal grainstones. This was a four part study including a lithological analysis of ten cores, a petrographical study of 97 thin sections, a petrophysical study of reservoir properties from core analyses and borehole logs, and predictive mapping of quality ranked flow units across the field. Examination of the cores and thin sections revealed H1a as the main pore type in Grayson field, which was a hybrid of both depositional and diagenetic processes with dominantly interparticle pores. The lowest ranked reservoir quality corresponded to intraparticle and intercrystalline pore types, which occurred mainly in the wackestone/mudstone and packstone/wackestone facies. The highest ranked reservoir quality corresponded to the H1a pore type which occurred mainly in the grainestone/packstone facies 1 and 2. The reservoir quality maps identified the spatial distribution of the facies within the field, which could be used to locate zones for possible in-fill drilling. These results should aid in the economical development of Grayson field and other similar fields.Item Experimental studies of unstart dynamics in inlet/isolator configurations in a Mach 5 flow(2009-05) Wagner, Justin Lawrence; Clemens, Noel T.The dynamics of the unstart process in inlet / isolator models mounted to the floor of a Mach 5 wind tunnel are investigated experimentally. The most extensively studied model has an inlet section that contains a 6-degree compression ramp and the isolator is a rectangular straight duct that is 25.4 mm high by 50.8 mm wide by 242.3 mm long. Unstart is initiated by raising a motor-driven flap that is located at the downstream end of the isolator section. Unstart proceeds with the formation of a shock system that propagates upstream at an average velocity of about 37 m/s (in the lab frame of reference), which is five percent of the freestream velocity. Unstart is seen to be associated with strong shock-induced separation that leads to reverse flow velocities up to about 300 m/s as measured by PIV. Both the schlieren imaging and PIV data suggest the dynamics and flow structure of the unstart process are dependent on inlet geometry. Furthermore, the PIV data indicate the unstart process to be highly three-dimensional. Finally, tripping the ceiling and sidewall boundary layers was seen to result in slower unstart processes. In addition, results are presented for 0-degree (no inlet) and 8-degree inlet / isolator models. In the 0-degree model, the experimental data show that the flow structure and propagation velocities of the unstart shock system are much more constant than those measured in unstart events with an inlet. In addition, an increased inlet compression angle appears to result in an increased unstart propagation velocity in the isolator. This is possibly related to the fact that with an increased compression ramp angle, the unstart shock system propagates against a lower momentum opposing flow. Furthermore, the inlet geometry is also seen to affect the flow that follows the unstart process. Experiments were also conducted with each of the three inlets attached to a shortened isolator. The short-isolator experiments showed it was possible to form a stable high-compression shock system in the isolator by raising the flap. This was not the case in longer isolator tests.Item Flow in multitasking : the effects of motivation, artifact, and task factors(2014-08) Park, Ji Hyun, active 21st century; Bias, Randolph G.The aims of this dissertation study are 1) to examine how the interplay of motivation, artifacts, and task interconnectedness affect users' flow experience, 2) to understand users' multitasking patterns by analyzing approaches and strategies in multitasking environments through a participatory design session, and 3) to come up with design insights and implications for desired multitasking environments based on findings from the quantitative and qualitative data analysis and synthesis. This dissertation employed the PAT (Person-Artifact-Task) model to examine factors that affect users' flow experience in computer-mediated multitasking environments. Particularly, this study focused on users' flow experience - sense of control, focused attention, curiosity, intrinsic interest and interactivity - in the context of multitasking. The dissertation begins with perspectives on human multitasking research from various disciplines. Emphasis is placed on how researchers have defined the term multitasking and the scope of previous multitasking research. In addition, this study provides definitions of the term task switching, which also has been used to describe human multitasking. The second section of this dissertation focuses on the literature, which characterizes factors and theoretical frameworks of human multitasking research. In this section, human multitasking factors were classified into internal and external factors to analyze factors from the micro to the macro perspective. More detailed definitions and comparisons are also addressed. To summarize and conclude the literature review, this study provides a synthesis framework of internal and external factors of human multitasking contexts. In section III, this dissertation introduces theoretical frameworks that include the constructs of the PAT (Person-Artifact-Task) model and flow model. The next three sections present the research design and two research methods - the experiment and participatory design. The results and discussion section includes the implications of interpreting people's flow experience with motivation, artifact (technology affordance type), and task interconnectedness through the PAT model. The study findings and implications should extend our understanding of multitasking behaviors and contexts and how the interplay of person, artifact, and task factors affects humans' flow experience. A concluding chapter explores future work and design implications on how researchers and designers can take contextual factors into consideration to identify the most effective multitasking in computer-mediated environments.Item Flow Past a Sphere and a Prolate Spheroid at Low Reynolds Numbers(2013-12-04) Zhang, YoufengThe present work carries out numerical simulations of viscous incompressible flow past a sphere or a spheroid at low Reynolds numbers. When the flow passes a sphere or a spheroid, the flow will have its motion changed because of the shear stress from the surface of the object. This change of motion also differs at different Reynolds numbers based on the geometry of the sphere or spheroid. Many fluids researchers have conducted experiments to investigate the variations of the flow past a sphere at low Reynolds numbers. But the research on flow past a spheroid mainly focuses on cases at high Reynolds numbers (Re>105). Up to date, numerical study on flow past a spheroid at low and intermediate Reynolds numbers (<1000) has not been done thoroughly. The first part of this work is to investigate variations of the flow past a sphere occurring with increasing Reynolds number up to 400. The code used in this thesis is OpenFOAM which is an open source package providing a solver based on the Finite Volume Method. To verify the accuracy of the simulations by the code, results for velocity, vorticity and drag coefficient at very low Reynolds number (Re<0.1) are compared with exact solutions by Stokes Law. Then variations of the flow pattern are displayed up to Reynolds number 400. Some characteristics such as the drag coefficient, wake length and wake angle are recorded for contrast with data in publications. The wake length and separation angle both show logarithmic relationship with the Reynolds number. Flow patterns such as streamline around the sphere and periodic shedding are also discussed on the ground of previous knowledge. The second part will investigate the flow past a prolate spheroid. Discussion on this topic is developed in the regime of low Reynolds number (Re<1000). The present work investigates cases at very low Reynolds numbers (Re<0.1) and compares the results with exact solutions predicted by previous researchers. For higher Reynolds numbers, present work mainly focuses on studying variations of the drag coefficient with the Reynolds number and aspect ratio. The simulation shows that a spheroid has larger drag coefficient than a sphere at lower Reynolds numbers and then tends to be the smaller one for higher Reynolds numbers.Item Food service establishment wastewater characterization and management practice evaluation(Texas A&M University, 2006-04-12) Garza, Octavio ArmandoFood service establishments that use onsite wastewater treatment systems are experiencing hydraulic and organic overloading of pretreatment systems and/or drain fields. Design guidelines for these systems are typically provided in State regulations and based on residential hydraulic applications. For the purposes of this research, hydraulic loading indicates the daily flow of water directed to the wastewater system. Organic loading refers to the composition of the wastewater as quantified by five-day biochemical oxygen demand (BOD5), total fats, oils and greases (FOG), and total suspended solids (TSS). The first part of this study included an analysis of the central tendencies of analytical data of four wastewater parameters from 28 restaurants representing a broad spectrum of restaurant types. Field sampling consisted of two sets of grab samples collected from each restaurant for six consecutive days at approximately the same time each day. These sets were collected approximately two weeks apart. The numerical data included BOD5, FOG, and TSS. The fourth parameter evaluated was daily flow. Data exploration and statistical analyses of the numerical data from the 28 restaurants was performed with the standard gamma probability distribution model in ExcelTM and used to determine inferences of the analytical data. The analysis shows higher hydraulic and organic values for restaurant wastewater than residential wastewater. The second part of the study included a statistical analysis of restaurant management practices and primary cuisine types and their influence on BOD5, FOG, TSS, and daily flow to determine if management practices and/or cuisine types may be influencing wastewater composition and flow. A self-reporting survey was utilized to collect management practice and cuisine type information. Survey response information and analytical data were entered into an ExcelTM spreadsheet and subsequently incorporated into SASTM statistical software for statistical analysis. Analysis indicated that the number of seats in a restaurant, use of self-serve salad bars, and primary cuisine types are statistically significant indicators of wastewater characteristics.Item Generation, stability, and transport of nanoparticle-stabilized oil-in-water emulsions in porous media(2014-05) Gabel, Scott Thomas; Bryant, Steven L.; Huh, ChunThe ability of nanoparticles to stabilize oil/water emulsions provides many interesting opportunities for the petroleum industry. Emulsions can be used as a displacing fluid for enhanced oil recovery to improve sweep efficiencies. Emulsions can be used to improve conformance control by effectively blocking thief zones in reservoirs with a high degree of heterogeneity. As shown in this thesis emulsions can be used to deliver fluids that contact and mobilize residual oil. It is imperative to understand emulsion behavior in porous media for design purposes in enhanced or improved oil recovery processes involving emulsions. Nanoparticle-stabilized oil-in-water emulsions were continuously generated by co-injecting aqueous nanoparticle dispersion and oil through a beadpack. There exists a critical shear rate below which a stable emulsion will not be generated. The critical shear rate increased with decreasing bead size. Above the critical shear rate, the droplet size of the generated emulsion was a function of shear rate and decreased with increasing shear rate. The stable emulsions were characterized by their droplet size and rheology. The emulsion viscosity was highly dependent upon droplet size and not the bulk oil viscosity in the emulsion. The emulsions were highly shear thinning and emulsions with smaller droplets were more viscous than emulsions with larger droplets. Highly stable emulsions that were generated by co-injection were collected, separated from excess phase(s) and injected into beadpacks. In most experiments the injected emulsion coalesced into the bulk fluids. Whether the bulk fluids generated a new emulsion in the bead pack depended on the shear rate, bead size, and initial saturation of the beadpack. Different beadpack experiments showed the transition from one flow regime to a second flow regime as the slow movement of a coalescence/regeneration front propagated through the beadpack. Coreflood experiments confirmed the mechanisms hypothesized for the beadpack emulsion injection experiments. When a stable emulsion was injected the effluent emulsion rheology and droplet size were altered solely as a result of being forced through sandstone cores, not because of fluids contacted within the core. The shear rate controlled whether the emulsion coalesced and produced no effluent emulsion, regenerated into an emulsion with larger droplets, or regenerated into an emulsion with smaller droplets. Oil recovery experiments showed that nanoparticle-stabilized oil-in-water emulsion increased the recovery of oil compared to a waterflood for cores with immobile and mobile oil. The mechanism is the coalesced oil droplets form a flowing phase that is miscible with oil present in the core and thus achieves a much more efficient displacement. The possible continuous generation and coalescence of droplets may have increased the apparent viscosity, improving the sweep efficiency of the emulsion injection. A novel oil recovery mechanism was shown in imbibition experiments where nanoparticle dispersion was used to displace oil. Large shear rates coupled with the affinity for nanoparticles at the oil water interface enabled residual oil to be mobilized, or for residual oil blobs to spawn smaller droplets that are stabilized by the nanoparticles and thus can be transported with the dispersion through the core.Item Increasing college students’ experience of flow while completing academic writing tasks(2015-05) Dearman, Jeremy Keith; Schallert, Diane L.; Weinstein, Claire E.; Patall, Erika A.; Pituch, Keenan A; Steinhardt, Mary AFlow is a state of consciousness where the individual experiences engagement, concentration, and enjoyment. An intervention was conducted focusing on challenge-skill balancing and intrinsic motivation, both previously conceptualized as aspects of flow. The variables evaluated were challenge-skill balance, concentration on task, flow, and intrinsic motivation. The study had 211 undergraduate college students (control = 104, intervention = 107). Repeated measures ANOVA was used to evaluate the data. The findings were mixed. Significant main effects between groups were not found. Significant main effects for time (pre-test to post-test) were found for challenge-skill balance, flow, and intrinsic motivation. A statistically significant change from pre-test to post-test for the control group on intrinsic motivation suggests the possible presence of a confounding effect by the control group curriculum. Some evidence was found that flow can be influenced by direct intervention. Further research is needed to clarify, evaluate, and extend these findings.Item Peaceman's numerical productivity index for non-linear flows in porous media(2009-08) Chang, Dahwei; Aulisa, Eugenio; Toda, Magdalena D.; Howle, Victoria E.From Darcy’s law to Darcy-Forchheimer equation, there have being a lot efforts finding solutions for flows in porous media. Peaceman used a system of well blocks to replace the well bore in finding numerical solutions for linear flows. Our work uses a single well block to find the pressure distribution throughout the well for non-linear flows. In the process we found a block invariant which can be used to build the pressure distribution formula. From it, we can find the productivity index, one of the important factors in petroleum engineering. Theoretical derivation and numerical data are also presented in this report.Item Simulation of fluid flow mechanisms in high permeability zones (Super-K) in a giant naturally fractured carbonate reservoir(2009-05-15) Abu-Hassoun, Amer H.Fluid flow mechanisms in a large naturally fractured heterogeneous carbonate reservoir were investigated in this manuscript. A very thin layer with high permeability that produces the majority of production from specific wells and is deemed the Super-K Zone was investigated. It is known that these zones are connected to naturally occurring fractures. Fluid flow in naturally fractured reservoirs is a very difficult mechanism to understand. To accomplish this mission, the Super-K Zone and fractures were treated as two systems. Reservoir management practices and decisions should be very carefully reviewed and executed in this dual continuum reservoir based on the results of this work. Studying this dual media flow behavior is vital for better future completion strategies and for enhanced reservoir management decisions. The reservoir geology, Super-K identification and natural fractures literature were reviewed. To understand how fluid flows in such a dual continuum reservoir, a dual permeability simulation model has been studied. Some geological and production iv data were used; however, due to unavailability of some critical values of the natural fractures, the model was assumed hypothetical. A reasonable history match was achieved and was set as a basis of the reservoir model. Several sensitivity studies were run to understand fluid flow behavior and prediction runs were executed to help make completion recommendations for future wells based on the results obtained. Conclusions and recommended completions were highlighted at the end of this research. It was realized that the natural fractures are the main source of premature water breakthrough, and the Super-K acts as a secondary cause of water channeling to the wellbore.Item The misguided reaction: reconsidering intelligence flow before 11 September 2001(Texas A&M University, 2004-11-15) Prothro, John SamuelThis research examines the story of 11 September 2001 from an organizational communication perspective. Discourse after the event pointed to "communication difficulties" as a scapegoat for the intelligence community's failure. These analyses are misguided. Therefore, I examine our government's answer to communication difficulties--more bureaucracy. The many communication hindrances associated with bureaucracy are discussed as reasons to rethink our government's reaction. Finally, further research and recommendations are discussed.Item Transverse Collective Flow and Emission Order of Mid-Rapidity Fragments in Fermi Energy Heavy Ion Collisions(2011-10-21) Kohley, Zachary WayneThe Equation of State (EoS) of asymmetric nuclear matter has been explored through the study of mid-rapidity fragment dynamics from the 35 MeV/u $^{70}$Zn $^{70}$Zn, $^{64}$Zn $^{64}$Zn, and $^{64}$Ni $^{64}$Ni systems. The experimental data was collected at the Texas A and M Cyclotron Institute using the 4 NIMROD-ISiS array, which provided both event characterization and excellent isotopic resolution of charged particles. The transverse collective flow was extracted for proton, deuteron, triton, 3He, alpha, and 6He particles. Isotopic and isobaric effects were observed in the transverse flow of the fragments. In both cases, the transverse flow was shown to decrease with an increasing neutron content in the fragments. The (N/Z)sys dependence of the transverse flow and the difference betwen the triton and 3He flow were shown to be sensitive to the density dependence of the symmetry energy using the stochastic mean-field model. A stiff parameterization of Esym(p) was found to provide better agreement with the experimental data. The transverse flow for intermediate mass fragments (IMFs) was investigated, providing a new probe to study the nuclear EoS. A transition from the IMF flow strongly depending on the mass of the system, in the most violent collisions, to a dependence on the charge of the system, for the peripheral reactions, was observed. Theoretical simulations were used to show that the relative differences in the IMF flow are sensitive to the density dependence of the symmetry energy. The best agreement between the experiment and theory was achieved with a stiff Esym(p). A new method was developed in which correlations between the projectile-like and mid-rapidity fragments were examined using a scaled flow. Theoretical simulations were used to show that the scaled flow of the particles was connected to their average order of emission. The experimental results suggest that the mid-rapidity region is preferentially populated with neutron-rich light charged particles and the Z=3-4 IMFs at a relatively early stage in the collision. This work presents additional constraints on the nuclear EoS and insight into the mid-rapidity dynamics observed in Fermi energy heavy-ion collisions.Item Turbulent boundary layers over receiver arrays(2010-05) Dolder, Craig Nealon; Tinney, Charles Edmund, 1975-; Haberman, Michael R.A study of the fluctuating wall pressure and unsteady velocity field in a flat plate turbulent boundary layer flow was conducted over a moderate range of Reynolds numbers to better understand the mechanisms by which the two fields are coupled. Individual and coincident measurements of the fluctuating pressure and velocity fields were acquired using a 20 element hydrophone array and a two-component Laser Doppler Anemometer, respectively. Estimates of the velocity power spectral density (PSD) revealed two primary trends predicted by turbulence theory, k⁻¹ in the region of (ky) = 10⁰ due to anisotropy of the large scales, and k⁻⁵/³ for larger values of (ky) where structures appear more isotropic. The mean velocity profiles, having been collapsed using outer scaling variables, exhibited the presence of a slightly adverse pressure gradient with a n = 6 power law shape. As for the fluctuating wall pressure, increased Reynolds numbers produced increases in the amplitude and frequency of the characteristic signatures from which the pressure spectral densities were also found to collapse reasonably well using outer scaling variables. The results suggest the location in the flow where the mechanisms responsible for driving the fluctuating wall pressure signatures reside. Space-time correlations and frequency-wavenumber analysis reveal a convective ridge in the fluctuating wall pressure corresponding to the passage of several organized structures at 75% of the free stream velocity for all Reynolds numbers tested.Item Two-particle correlations of identified particles in heavy ion collisions at STAR(2016-08) Bhattarai, Prabhat; Markert, Christina; Ray, Robert L. (Robert Landon); Bohm, Arno; Walker, Stephen; Onyisi, PeterThe study of quarks and their interactions through gluons has been an active area of research since their discovery. For two decades the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been dedicated to studying the interactions between quarks by producing nuclear matter in an extremely dense and hot environment. It has been hypothesized that colliding beams of atomic nuclei near the speed of light creates the hot and dense environment in which all quarks in the nuclei de-confine to form a short-lived state of matter called a Quark Gluon Plasma (QGP). Because of the short lifetime of QGP, it is impossible to observe it directly and, the only way to study such matter is through the final state particles. Two-particle correlation, which is defined using Pearson's normalized covariance, is one of the techniques to study the early interactions via the final state particles. A broad survey has been made to study the two-particle correlations of identified-charged hadrons (pi, K and p) in various ranges of momentum for the hadrons produced in √sNN=200 GeV Au+Au collisions at the STAR experiment at RHIC. A total of 2123 two-dimensional independent structures made by correlation coefficients in relative angular space in (eta, phi) for different combinations of identified hadrons have been studied. Correlations between any two identified particles contrasts to all-particle correlations giving an opportunity to study the contribution of each particle species in the hadronization processes. As a new feature, same-side anti-correlations are observed in both like-sign and unlike-sign pairs in certain yT bins and in certain identified particles. A significant feature of the final state distribution of particles is an azimuthal anisotropy which is defined as the second Fourier component; the amplitude is proportional to parameter v2. We report the measure of azimuthal anisotropy of identified hadrons for the first time and test for the factorization used in conventional analysis. The data presented here constitute a comprehensive measurement of the light-flavor, di-hadron density as function of collision centrality, transverse momentum and 2D relative angles in longitudinal (beam direction) and azimuthal directions.