Готові списки джерел за темами / Critical Flow Regime

Добірка наукової літератури з теми "Critical Flow Regime"

Автор: Grafiati
Опубліковано: 6 вересня 2023

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Статті в журналах з теми "Critical Flow Regime"

1

Dzhaugashtin, K. E. "The critical jet flow regime." Fluid Dynamics 25, no. 3 (1990): 335–39. http://dx.doi.org/10.1007/bf01049812.

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2

Gryparis, Evgenios, and Georgios C. Georgiou. "Annular Poiseuille flow of Bingham fluids with wall slip." Physics of Fluids 34, no. 3 (March 2022): 033103. http://dx.doi.org/10.1063/5.0086511.

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Анотація:
We consider the annular Poiseuille flow of a Bingham fluid with wall slip. First, the analytical solution is derived for the case in which Navier-slip conditions are applied at the two cylinders. A sliding (pure plug) regime is observed below a critical pressure gradient, and a yielding regime is eventually encountered above another critical pressure gradient in which the material yields near the two walls and moves as a plug in a core region. An intermediate semi-sliding regime is observed when different slip laws apply at the two walls in which the material yields only near the wall corresponding to weaker slip and the unyielded plug slides along the other. Next, we consider the case where wall slip occurs above a critical wall shear stress, the slip yield stress, which is taken to be less than the yield stress, in agreement with experimental observations. In this case, a no-flow regime is observed below a critical pressure gradient, followed by the sliding and yielding regimes. The critical values of the pressure gradient defining the various flow regimes are determined, and the closed-form solutions are provided for all cases. These are compared with available theoretical and experimental results in the literature.
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3

Viebahn, Jan, and Henk A. Dijkstra. "Critical Transition Analysis of the Deterministic Wind-Driven Ocean Circulation — A Flux-Based Network Approach." International Journal of Bifurcation and Chaos 24, no. 02 (February 2014): 1430007. http://dx.doi.org/10.1142/s0218127414300079.

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Анотація:
A new method for constructing complex networks from fluid flow fields is proposed. The approach focuses on spatial properties of the flow field, namely, on the topology of the streamline field. The network approach is applied to a model of the wind-driven ocean circulation, which exhibits the prototype of a critical transition, that is, a back-to-back saddle-node bifurcation related to two separate dynamical regimes. The network analysis enables a structural characterization of, on the one hand, the viscous regime as a weakly-connected and highly-assortative regime, and, on the other hand, of the inertial regime as a highly-connected and weakly-assortative regime. Moreover, the network analysis enables a robust early-warning signal of the critical transition emerging from the viscous regime: The upcoming global regime change induced by the critical transition may be anticipated by a drastic decrease in the overall closeness of the network, which reflects a preceding local regime change in the flow field. Hence, the results support the application of network-based topology measures complementary to time-series based statistical properties as leading indicators of critical transitions.
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4

Lamia, Hachemi Rachedi, Lakehal Moussa, and Achour Bachir. "Modern vision for critical flow in an egg-shaped section." Water Science and Technology 84, no. 4 (July 12, 2021): 840–50. http://dx.doi.org/10.2166/wst.2021.274.

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Анотація:
Abstract The critical regime plays a primordial role in the study of gradually varying flows by classifying flow regimes and slopes. Through this work, a new approach is proposed to analyze critical flow regime in an egg-shaped channel. Based on both the definition of Froude number and Achour and Bedjaoui general discharge relationship, a relation between critical and normal depths is derived and then graphically represented for the particular case of a smooth channel characterized by a generating diameter equal to 1 m. The results show the influence of the slope on the frequency of occurrence of the critical regime. At the same time and independently of the flow rate, a very advantageous approach for the calculation of the Froude number has been proposed. The study shows that there are six zones to differentiate the various flow states, namely: on the one hand for steep slopes two subcritical zones interspersed by a supercritical zone and on the other hand for mild slopes a zone corresponding to uniform flow, an area where the flow is probably gradually varied and finally an area where the flow is abruptly varied. Based on the specific energy equation, a validation process concluded that the proposed relationships were reliable.
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5

Yu, Liyuan, Richeng Liu, and Yujing Jiang. "A Review of Critical Conditions for the Onset of Nonlinear Fluid Flow in Rock Fractures." Geofluids 2017 (July 6, 2017): 1–17. http://dx.doi.org/10.1155/2017/2176932.

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Анотація:
Selecting appropriate governing equations for fluid flow in fractured rock masses is of special importance for estimating the permeability of rock fracture networks. When the flow velocity is small, the flow is in the linear regime and obeys the cubic law, whereas when the flow velocity is large, the flow is in the nonlinear regime and should be simulated by solving the complex Navier-Stokes equations. The critical conditions such as critical Reynolds number and critical hydraulic gradient are commonly defined in the previous works to quantify the onset of nonlinear fluid flow. This study reviews the simplifications of governing equations from the Navier-Stokes equations, Stokes equation, and Reynold equation to the cubic law and reviews the evolutions of critical Reynolds number and critical hydraulic gradient for fluid flow in rock fractures and fracture networks, considering the influences of shear displacement, normal stress and/or confining pressure, fracture surface roughness, aperture, and number of intersections. This review provides a reference for the engineers and hydrogeologists especially the beginners to thoroughly understand the nonlinear flow regimes/mechanisms within complex fractured rock masses.
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6

Kunii, Kohei, Takahiro Ishida, Yohann Duguet, and Takahiro Tsukahara. "Laminar–turbulent coexistence in annular Couette flow." Journal of Fluid Mechanics 879 (October 1, 2019): 579–603. http://dx.doi.org/10.1017/jfm.2019.666.

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Анотація:
Annular Couette flow is the flow between two coaxial cylinders driven by the axial translation of the inner cylinder. It is investigated using direct numerical simulation in long domains, with an emphasis on the laminar–turbulent coexistence regime found for marginally low values of the Reynolds number. Three distinct flow regimes are demonstrated as the radius ratio $\unicode[STIX]{x1D702}$ is decreased from 0.8 to 0.5 and finally to 0.1. The high-$\unicode[STIX]{x1D702}$ regime features helically shaped turbulent patches coexisting with laminar flow, as in planar shear flows. The moderate-$\unicode[STIX]{x1D702}$ regime does not feature any marked laminar–turbulent coexistence. In an effort to discard confinement effects, proper patterning is, however, recovered by artificially extending the azimuthal span beyond $2\unicode[STIX]{x03C0}$. Eventually, the low-$\unicode[STIX]{x1D702}$ regime features localised turbulent structures different from the puffs commonly encountered in transitional pipe flow. In this new coexistence regime, turbulent fluctuations are surprisingly short-ranged. Implications are discussed in terms of phase transition and critical scaling.
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7

Sarraf Shirazi, Alireza, and Ian Frigaard. "SlurryNet: Predicting Critical Velocities and Frictional Pressure Drops in Oilfield Suspension Flows." Energies 14, no. 5 (February 25, 2021): 1263. http://dx.doi.org/10.3390/en14051263.

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Анотація:
Improving the accuracy of the slurry flow predictions in different operating flow regimes remains a major focus for multiphase flow research, and it is especially targeted at industrial applications such as oil and gas. In this paper we develop a robust integrated method consisting of an artificial neural network (ANN) and support vector regression (SVR) to estimate the critical velocity, the slurry flow regime change, and ultimately, the frictional pressure drop for a solid–liquid slurry flow in a horizontal pipe, covering wide ranges of flow and geometrical parameters. Three distinct datasets were used to develop machine learning models with totals of 100, 325, and 125 data points for critical velocity, and frictional pressure drops for heterogeneous and bed-load regimes respectively. For each dataset, 80% of the data were used for training and the rest 20% for evaluating the out of sample performance. The K-fold technique was used for cross-validation. The prediction results of the developed integrated method showed that it significantly outperforms the widely used existing correlations and models in the literature. Additionally, the proposed integrated method with the average absolute relative error (AARE) of 0.084 outperformed the model developed without regime classification with the AARE of 0.155. The proposed integrated model not only offers reliable predictions over a wide range of operating conditions and different flow regimes for the first time, but also introduces a general framework of how to utilize prior physical knowledge to achieve more reliable performances from machine learning methods.
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8

CHURILOV, S. M. "Nonlinear stability of a stratified shear flow in the regime with an unsteady critical layer. Part 2. Arbitrary stratification of asymmetric flow." Journal of Fluid Mechanics 392 (August 10, 1999): 233–75. http://dx.doi.org/10.1017/s0022112099005443.

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Анотація:
A weakly nonlinear analysis of the downstream evolution of weakly unstable disturbances in a stably stratified mixing layer with a large Reynolds number is carried out. No other requirements are imposed upon velocity and density profiles, thus making it possible to overcome the restrictions placed in earlier studies (Brown & Stewartson 1978; Brown et al. 1981; Churilov & Shukhman 1987, 1988) by a particular choice of weakly supercritical flow models assuming symmetry. For each of the two critical layer regimes possible here, viscous and unsteady, evolution equations are obtained, their solutions and competition between nonlinearities in the course of instability development are analysed, and evolution scenarios for unstable disturbances are constructed for different levels of their supercriticality. It is established that the regime with a nonlinear critical layer does not arise in an evolutionary manner, except for the previously studied case of a weak stratification (Shukhman & Churilov 1997). It is shown that while in the viscous critical layer regime the relaxation of assumptions of the symmetry and weak supercriticality of the flow produces no fundamental changes in the theory, in the unsteady critical layer regime a new (non-dissipative cubic) nonlinearity appears which governs the instability development on equal terms with two already known nonlinearities. Results are illustrated by calculations for two families of flow models with a controlled degree of asymmetry.
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9

Ahmed, A., R. Manzoor, S. U. Islam, and H. Rahman. "Numerical investigation for flow over a square rod through a passive control method at various Reynolds numbers." Canadian Journal of Physics 98, no. 5 (May 2020): 425–32. http://dx.doi.org/10.1139/cjp-2019-0155.

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Анотація:
This work presents a numerical simulation performed to study the effect of Reynolds number (Re = 80–200) on fluid flow over a square rod attached to two small controlling rods using the Lattice Boltzmann method. For this reason, the spacing ratio between the control rods and main rod varies systematically from g = 0.5–5. Flow has been subdivided into three flow regimes based on spacing ratios. The first flow regime is considered at a small gap (g = 0.5, 1, and 1.5), the second flow regime is obtained at a moderate gap (g = 2, 2.5, and 3), and the third flow regime is considered a at large gap (g = 4–5). Five different types of flow modes were noticed in the given flow regimes. The values Re = 200 and g = 5 were found to be critical due to a sudden change in flow characteristics. The maximum value of Cdmean is 0.869 and the largest percent reduction (65.15%) in the mean drag coefficient was found at Re = 200 and g = 2.
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10

Merritt, Angela, Belize Lane, and Charles Hawkins. "Classification and Prediction of Natural Streamflow Regimes in Arid Regions of the USA." Water 13, no. 3 (February 1, 2021): 380. http://dx.doi.org/10.3390/w13030380.

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Анотація:
Understanding how natural variation in flow regimes influences stream ecosystem structure and function is critical to the development of effective stream management policies. Spatial variation in flow regimes among streams is reasonably well understood for streams in mesic regions, but a more robust characterization of flow regimes in arid regions is needed, especially to support biological monitoring and assessment programs. In this paper, we used long-term (41 years) records of mean daily streamflow from 287 stream reaches in the arid and semi-arid western USA to develop and compare several alternative flow-regime classifications. We also evaluated how accurately we could predict the flow-regime classes of ungauged reaches. Over the 41-year record examined (water years 1972–2013), the gauged reaches varied continuously from always having flow > zero to seldom having flow. We predicted ephemeral and perennial reaches with less error than reaches with an intermediate number of zero-flow days or years. We illustrate application of our approach by predicting the flow-regime classes at ungauged reaches in Arizona, USA. Maps based on these predictions were generally consistent with qualitative expectations of how flow regimes vary spatially across Arizona. These results represent a promising step toward more effective assessment and management of streams in arid regions.
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Більше джерел

Дисертації з теми "Critical Flow Regime"

1

Li, Shi-Ming. "Mean-Field Free-Energy Lattice Boltzmann Method for Liquid-Vapor Interfacial Flows." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/29621.

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Анотація:
This dissertation includes a theoretical and numerical development to simulate liquid-vapor flows and the applications to microchannels. First, we obtain a consistent non-local pressure equation for simulating liquid-vapor interfacial flows using mean-field free-energy theory. This new pressure equation is shown to be the general form of the classical van der Waals" square-gradient theory. The new equation is implemented in two-dimensional (2D) D2Q7, D2Q9, and three-dimensional (3D) D3Q19 lattice Boltzmann method (LBM). The three LBM models are validated successfully in a number of analytical solutions of liquid-vapor interfacial flows. Second, we have shown that the common bounceback condition in the literature leads to an unphysical velocity at the wall in the presence of surface forces. A few new consistent mass and energy conserving velocity-boundary conditions are developed for D2Q7, D2Q9, and D3Q19 LBM models, respectively. The three LBM models are shown to have the capabilities to successfully simulate different wall wettabilities, the three typical theories or laws for moving contact lines, and liquid-vapor channel flows. Third, proper scaling laws are derived to represent the physical system in the framework of the LBM. For the first time, to the best of the author's knowledge, we obtain a flow regime map for liquid-vapor channel flows with a numerical method. Our flow map is the first flow regime map so far for submicrochannel flows, and also the first iso-thermal flow regime map for CO₂ mini- and micro-channel flows. Our results show that three major flow regimes occur, including dispersed, bubble/plug, and liquid strip flow. The vapor and liquid dispersed flows happen at the two extremities of vapor quality. When vapor quality increases beyond a threshold, bubble/plug patterns appear. The bubble/plug regimes include symmetric and distorted, submerged and non-wetting, single and train bubbles/plugs, and some combination of them. When the Weber number<10, the bubble/plug flow regime turns to a liquid strip pattern at the increased vapor quality of 0.5~0.6. When the Weber number>10, the regime transition occurs around a vapor quality of 0.10~0.20. In fact, when an inertia is large enough to destroy the initial flow pattern, the transition boundary between the bubble and strip regimes depends only on vapor quality and exists between x=0.10 and 0.20. The liquid strip flow regimes include stratified strip, wavy-stratified strip, intermittent strip, liquid lump, and wispy-strip flow. We also find that the liquid-vapor interfaces become distorted at the Weber number of 500~1000, independent of vapor quality. The comparisons of our flow maps with two typical experiments show that the simulations capture the basic and important flow mechanisms for the flow regime transition from the bubble/plug regimes to the strip regimes and from the non-distorted interfaces to the distorted interfaces. Last, our available results show that the flow regimes of both 2D and 3D fall in the same three broad categories with similar subdivisions of the flow regimes, even though the 3D duct produces some specific 3D corner flow patterns. The comparison between 2D and 3D flows shows that the flow map obtained from 2D flows can be generally applied to a 3D situation, with caution, when 3D information is not available. In addition, our 3D study shows that different wettabilities generate different flow regimes. With the complete wetting wall, the flow pattern is the most stable.
Ph. D.
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2

Andersson, Nyberg Adrian. "Combining hydrologic modelling and boundary shear stress estimates to evaluate the fate of fine sediments in river Juktån : Impact of ecological flows." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-145948.

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Анотація:
Altered flow regimes following river regulation can result in significant changes in river bed geomorphology and subsequent negative ecological impacts caused by re-suspended sediments deposited on the riverbed. This study aimed to evaluate the consequences of implementing an ecological flow regime on sediments accumulated within the regulated river Juktån. Sediments were sampled and analysed for particle size distribution to estimate sediment stability. Flow alteration following the ecological flow regime was analysed with HEC-RAS unsteady flow simulation serving as a basis for calculations of forces acting to erode or retain deposited sediments. Additional analyses regarding critical flow were made with HEC-RAS steady flow simulation. Results show that 4 out of 15 cross-sections analysed would have the potential to erode and re-suspend sediments. The estimated average critical flow for when sediments become unstable with potential to re-suspend is 17 m3/s. The total sediment inventory of the studied reach is ~25000 ton, with ~3000-ton sediments potentially eroding into re-suspension. This is approximately 3% of river Umeälvens annual 100 000 ton suspended sediments before being regulated. Results indicate that river bed heterogeneity in river Juktån could benefit from implementing the ecological flow regime while not mobilizing such amounts of fine sediments that would cause clogging effects downstream the site of interest. The study also introduces the erosion rate equation which compares the annual erosion between two different flow regimes.
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3

Tebowei, Roland. "Computational fluid dynamics (CFD) modelling of critical velocity for sand transport flow regimes in multiphase pipe bends." Thesis, Robert Gordon University, 2016. http://hdl.handle.net/10059/2118.

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Анотація:
The production and transportation of hydrocarbon fluids in multiphase pipelines could be severely hindered by particulate solids deposit such as produced sand particles which accompany hydrocarbon production. Knowledge of the flow characteristics of solid particles in fluids transported in pipelines is important in order to accurately predict solid particles deposition in pipelines. This research thesis presents the development of a three-dimensional (3D) Computational Fluids Dynamics (CFD) modelling technique for the prediction of liquid-solids multiphase flow in pipes, with special emphasis on the flow in V-inclined pipe bends. The Euler-Euler (two-fluid) multiphase modelling methodology has been adopted and the multiphase model equations and closure models describing the liquid-solids flow have been implemented and calculated using the finite volume method in a CFD code software. The liquid phase turbulence has been modelled using a two-equation k−ε turbulence model which contains additional terms to account for the effects of the solid-particles phase on the multiphase turbulence structure. The developed CFD numerical framework has been verified for the relevant forces and all the possible interaction mechanisms of the liquid-solids multiphase flow by investigating four different numerical frameworks, in order to determine the optimum numerical framework that captures the underlying physics and covers the interaction mechanisms that lead to sand deposition and the range of sand transport flow regimes in pipes. The flow of liquid-sand in pipe has been studied extensively and the numerical results of sand concentration distribution across pipe and other flow properties are in good agreement with published experimental data on validation. The numerical framework has been employed to investigate the multiphase flow in V-inclined pipe bends of ±4o−6o, seemingly small inclined bend angles. The predicted results which include the sand segregation, deposition velocity and flow turbulence modulation in the pipe bend show that the seemingly small pipe bends have significant effect on the flow differently from that of horizontal pipes. The pipe bend causes abrupt local change in the multiphase flow characteristic and formation of stationary sand deposit in the pipe at a relatively high flow velocity. The threshold velocity to keep sand entrained in liquid in pipe bends is significantly higher than that required for flow horizontal pipes. A critical implication of this is that the correlations for predicting sand deposition in pipelines must account for the effect of pipe bend on flow characteristics in order to provide accurate predictions of the critical sand transport velocity (MTV) in subsea petroleum flowlines, which V-inclined pipe bends are inevitable due to seabed topology.
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4

Dogan, Huseyin Ali. "Investigation Of Bit Hydraulics For Gasified Drilling Fluids." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/12604906/index.pdf.

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Анотація:
Accurate determination of the pressure losses at the bit is very important for drilling practices in petroleum industry. In the literature, there are several studies on determination of the pressure losses. Major focus is concentrated on single phase drilling fluids, which is far from accurate estimation of pressure losses for multiphase fluids, i.e., fluids including a liquid and a gas phase, at the bit. Some of these models are valid for multiphase fluids, however, they are either valid for very high gas flow rates, or developed using very strong assumptions. This study presents a mathematical model for calculating bit hydraulics for gasified drilling fluids. The theory, which is valid for both sonic (critical) and subsonic (sub-critical) regimes, is based on the solution of the general energy equation for compressible fluid flow. The model is sensitive to changes in internal energy, temperature and compressibility. In addition, the model uses &ldquo
mixture sound velocity&rdquo
approach. A computer program is developed based on the proposed mathematical model. The program calculates pressure drop through a nozzle in subsonic flow region, and suggest flow rate if the calculated pressure drop values is in the sonic flow pressure ranges. The program has been run at reasonable field data. The results of the models have been compared with the results of existing models in the literature. The results show that the pressure losses through the bit can be estimated with a variation less than 9%. Also, it has been observed that bottom hole pressure, velocity of the liquid phase and nozzle size have a strong influence on bit pressure drop.
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5

Gupta, Pradeep. "Studies on Mixing Characteristics in the Critical Flow Regime of Supersonic Ejectors." Thesis, 2021. https://etd.iisc.ac.in/handle/2005/5576.

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Анотація:
Ejectors are passive devices having ubiquitous applications in several engineering domains, including modern-day applications in supercritical CO2-based power and refrigeration cycles. The ejector compresses a low-enthalpy fluid (secondary flow) through gasdynamic interactions with a co-flowing high-enthalpy fluid (primary flow). The ejector operates in the critical mode when the secondary flow is choked aerodynamically, and the entrainment ratio (ER, ratio of secondary to primary mass flow rate) becomes independent of the compression ratio (CR, ratio of the ejector exit pressure to the secondary flow stagnation pressure). In the mixed mode of operation, the ER decreases with CR. Applications of ejectors in energy conversion systems prefer the critical mode of operation. Ejectors have been studied using experimental, analytical, and computational tools with an emphasis on evaluating performance parameters. The gasdynamic mixing which drives the performance of the ejector is not well understood. An optical diagnostic evaluation of mixing in the ejector has been performed for the mixed mode of operation. The mixing characteristics and flow structures inside an ejector are not reported for the critical mode operation, which is the prime motive of this work. With an aim to achieve the critical flow regime, eight mixing duct geometries of different lengths and heights and three supersonic nozzles are designed and fabricated. Experiments are conducted in the supersonic ejector facility at Laboratory for Hypersonic and Shockwave Research, Indian Institute of Science, Bengaluru. Mass flow rate measurements yield the ER, and the static pressure profile indicates the mixing progress and compression. High-speed schlieren images are captured to observe unsteady flow features. Mixing characteristics in terms of non-mixed length (Lnm) is quantified using the planar laser Mie-scattering technique. Modal analyses (proper orthogonal decomposition and dynamic mode decomposition) are implemented on schlieren images to determine the spatial modes and associated frequencies of the re-compression shock structures observed in the diffuser. Additionally, Fourier spectrum analysis and continuous wavelet transformation are performed on the pressure signals. The designed ejectors operate in the critical flow regime, which is confirmed by experimentally measured ER response with CR. Lnm in the critical flow regime is 55% higher than in the mixed flow regime. The ER remains unchanged for mixing duct length less than Lnm; after that, it increases until L/H (mixing duct length to height ratio) of 15 and then decreases. There is a maximum area ratio corresponding to maximum ER for a given primary nozzle, beyond which ER decreases. The oscillation of re-compression shock structures is multimodal, with frequencies ranging between 100 – 250 Hz. A new non-dimensional frequency scaling of the dominant re-compression shock frequency is proposed, which is constant at 4.12+/-18. An artificial neural network (ANN) model is developed with a topology of seven input parameters representing the geometry, operating conditions, and working fluid characteristics for two output parameters of entrainment ratio (ER) and the operational regime (OR) of the ejector. The trained ANN model predicts the ER with +/-10% error and classifies the operating regime with 91% accuracy.
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6

Blackmore, Adam. "The Use of End Plates for a Cylinder in the Sub-critical Flow Regime." Thesis, 2011. http://hdl.handle.net/1807/29494.

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Анотація:
Experiments were conducted in a free-surface, re-circulating water channel to determine the dependence of spanwise flow uniformity in the near wake of a circular cylinder on the end conditions using Particle Image Velocimetry. The Reynolds number was 10,000. The end conditions consisted of plates with different leading edge geometries and configurations. A cylinder bounded by two endplates with sharp leading edge geometry generated the most uniform near wake. The horseshoe vortex dynamics in the cylinder/ wall and cylinder/endplate junctions were also studied. Upstream flow separation significantly altered the behavior of the horse shoe vortices. Periodic horse shoe vortex oscillation was found for experiments with the upstream flow attached; this periodic oscillation was disrupted with the presence of upstream flow separation. The endplate leading edge distance was also investigated. The oscillation frequency of the horse shoe vortex system was found to decrease with increasing leading edge distance.
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7

Chin-TsungWang and 王津琮. "Experimental investigations on initial transition of flow over a circular cylinder from the sub-critical to pre-critical regime." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/39708847463171251300.

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Анотація:
碩士
國立成功大學
航空太空工程學系碩博士班
101
This study aims to investigate the phenomenon of flow around a circular cylinder at Reynolds numbers between 1.7×105 and 4×105. The pressure taps signals on the circular cylinder were used to determine the pre-critical regime B state regime, the pre-critical regime A state regime and the one bubble regime. The experiment used different circular cylinders characterized by different relative roughness. Velocity measurements were carried out with a single hot-wire situated in the wake region. Both of the pressure and velocity signals obtained were analyzed with fast Fourier and Wavelet transformations. This study shows that in the case of different surface relative roughness cases, different flow states are observable, and pressure coefficients in the pre-critical regime B state regime, in the pre-critical regime A state regime and in the one bubble regime were obtained. In order to understand more features about flow over the circular cylinder, we used Thermal tuft to measure the separation angle and the separation bubble, meanwhile the wake flow was measured by hot-wire. Finally, by the method of Empirical Mode Decomposition, these two components were extracted separately from the raw signals. Subsequent data analysis on each component provided more insights into the characteristic behaviors of State A.
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8

Meng-ChiaoChen and 陳孟巧. "Investigations of Transition Phenomenon of the Flow around a Circular Cylinder in the Critical Regime." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/86375561413599384706.

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9

Hsu, Wei-ting, and 許瑋婷. "Investigations of wake flow of a circular cylinder in the critical regime by MEMS film sensors array." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/15000169017029822366.

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Анотація:
碩士
國立成功大學
航空太空工程學系碩博士班
96
An experimental investigation of flow around a smooth circular cylinder was carried out in a transonic wind tunnel,at Reynolds numbers 4.1x105~5.67x105,corresponding the Mach numbers in a range of 0.4 to 0.7. Unsteady characteristics of flow separation were studied with an array of self-made micro-electrical-mechanical-system (MEMS) film sensors, which were flushed with the cylinder surface, aligned in the circumferential direction. By correlation analysis of the signals obtained by two neighboring sensors, it is found that the location of flow separation can be identified by comparing the correlation coefficients obtained, which falls in the region where the correlation coefficients drops pronouncedly along the circumferential direction. By FFT analysis of the signals of each MEMS sensor, an interesting feature noted is that in the neighborhood of the flow separation pioint, the signal fluctuations contain a harmonic component of the vortex shedding frequency. Further, the results obtained by Hilbert-Huang Transformation of the signals measured indicate that downstream of the flow separation point, the fluctuating energy contained in the vortex shedding frequency component was reduced greatly. Since the experiments were made in a transonic wind tunnel, the effect of flow compressibility was discussed. As noted, through the present Reynolds numbers studied, the Strouhal numbers corresponding to the vortex shedding frequencies reduced remained about 0.2, distinguished different from those reported by the studies made in the low-speed wind tunnels, in the regime of the critical Reynolds numbers.
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Tsai, Hsing-Wen, and 蔡星汶. "Experimental Investigations of Flows Around Circular Cylinders in the Critical Regime." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/95194954393300496105.

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碩士
國立成功大學
航空太空工程學系碩博士班
94
In this study, we investigated the aerodynamic characteristics of the flows around circular cylinders at Reynolds numbers 1.73×10^5~5.86×10^5. First of all, the base pressures across the critical regime were measured, therefore the relation between base-pressure coefficient and Reynolds number was reduced. Then, we determined the lowest Reynolds number at which the flow field entered the one-bubble regime by comparing the root-mean-square values of the pressure coefficients on two sides of a cylinder. In this way, all the sub-regimes in the critical regime were classified. 　After the ranges of Reynolds number in each of the sub-regimes had been confirmed, the pressure distributions around circular cylinders at four specific Reynolds numbers were measured. By comparing the results of oil-flow visualization with the pressure measurements, the positions where laminar/turbulent separation and reattachment took place were successfully identified. Subsequently, the lift and drag coefficients by integrating the pressure distributions on the surface of circular cylinders were made. 　We analyzed the instantaneous behavior of vortex shedding by processing the measured data with wavelet transformation. This method offers instantaneous information that fast Fourier transformation can not provide. At the Reynolds number near lower end of one bubble regime, the unsteadiness of a bubble causes the instantaneous frequency of vortex shedding to vary discontinuously and fluctuate violently. 　At last, by comparing the above results with references, the flow quality of the ABRI wind tunnel was verified.
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Книги з теми "Critical Flow Regime"

1

M, Ishii, U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Systems Research., and Argonne National Laboratory, eds. Flow visualization study of post critical heat flux region for inverted bubbly, slug and annular flow regimes. Washington, D.C: Division of Systems Research, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1988.

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Barsky, Eugene. Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8838-3.

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Critical regimes of two-phase flows with a polydisperse solid phase. Dordrecht: Springer, 2010.

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Cathcart, Adam, Christopher Green, and Steven Denney, eds. Decoding the Sino-North Korean Borderlands. NL Amsterdam: Amsterdam University Press, 2021. http://dx.doi.org/10.5117/9789462987562.

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Since the 1990s, the Chinese-North Korean border region has undergone a gradual transformation into a site of intensified cooperation, competition, and intrigue. These changes have prompted a significant volume of critical scholarship and media commentary across multiple languages and disciplines. Drawing on existing studies and new data, Decoding the Sino-North Korean Borderlands brings much of this literature into concert by pulling together a wide range of insight on the region's economics, security, social cohesion, and information flows. Drawing from multilingual sources and transnational scholarship, this volume is enhanced by the extensive fieldwork undertaken by the editors and contributors in their quests to decode the borderland. In doing so, the volume emphasizes the link between theory, methodology, and practice in the field of Area Studies and social science more broadly.
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5

Barsky, Eugene. Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase. Springer London, Limited, 2012.

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Barsky, Eugene. Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase. Springer, 2010.

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7

Al-Sahan, Muzahem Abdulraham. On the development of the flow regimes and the formulation of a mechanistic non-equilibrium model for critical two-phase flow. 1988.

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8

Thompson, Alexander. Political and Legal Challenges. Edited by Kevin R. Gray, Richard Tarasofsky, and Cinnamon Carlarne. Oxford University Press, 2016. http://dx.doi.org/10.1093/law/9780199684601.003.0007.

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This chapter explores the interplay between politics and international law in the field of climate finance, with an emphasis on its North-South dimensions, which is the promotion of resource flows by developed nations towards developing nations. Participation by developing countries in the climate regime is critical as they are the largest emitters of greenhouse gas. Unfortunately, it is the less-developed nations that are harmed the most by climate change. It is here where North-South finance emerges as an important issue. The chapter addresses two critical issues in the governance and future of the climate finance regime. First, the wide variety of institutions and mechanisms involved expands the scope for attracting and supplying resources but they remain fragmented and require greater coordination to be effective. Second, the mobilization of North-South finance is insufficient relative to mitigation and adaptation needs. Such a challenge requires greater political will and a stronger legal regime.
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9

Idler, Annette, and Juan Carlos Garzón Vergara, eds. Transforming the War on Drugs. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197604359.001.0001.

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This book asks how the international community can tackle the complex causes and consequences that the War on Drugs is intended to address. This question arises against the backdrop of the War on Drugs’ failure to significantly reduce the scale or impact of illicit drug production and trafficking as well as the lack of consensus on the way forward in the international policy debate. Challenging conventional defense- and security-sector thinking, this book constitutes the first comprehensive, systematic effort to theoretically, conceptually, and empirically investigate the effects of the international drug control regime’s interpretation as War on Drugs. The volume unpacks the dynamics behind illicit drug markets, the fluid motivations of ‘warriors’, and the evolving consequences for ‘victims’ of this war—the lines between warriors and victims often being blurred. The contributors trace the regime’s interpretation as War on Drugs across vulnerable regions including South and Central America, West Africa, the Middle East and the Golden Crescent, the Golden Triangle, and Russia. They demonstrate that consequences are ‘glocal,’ the repercussions of transnational illicit flows being interdependent with the War’s local impacts on human rights, security, development, and public health. The book further reveals how the War has influenced government positions across these regions, with significant ramifications for the international drug control regime. At a time when global order is in flux and global security at risk, critically evaluating the regime’s securitization through the War on Drugs provides key insights into other global governance realms.
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Pilcher, Jeffrey M., ed. The Oxford Handbook of Food History. Oxford University Press, 2012. http://dx.doi.org/10.1093/oxfordhb/9780199729937.001.0001.

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This book chronicles the history of food. It starts with the Columbian Exchange, a term coined in 1972 by the historian Alfred Crosby to refer to the flow of plants, animals and microbes across the Atlantic Ocean and beyond. It then explores the spice trade during the medieval period, the social biography and politics of food, and how food history is connected with race and ethnicity in the United States. The book also focuses on cookbooks as an important primary source for historians; contemporary food ethics, ethical food consumerism, and “ethical food consumption”; the link between food and social movements; the emerging critical nutrition studies; the relationship between food and gender and how gender can enlighten the study of food activism; the relationship between food and religion; the debates over food as they have developed within geography in both the English- and French-speaking worlds; food history as part of public history; culinary tourism; national cuisines; food regimes analysis; how the Annales School in France has shaped the field of food history; the role of food in anthropology; a global history of fast food, focusing on the McDonald's story; industrial foods; and the merits of food studies and its lessons for sociology. In addition, the book assesses the impact of global food corporations' domination in the contemporary era, which in many ways can be seen as the equivalent of the European and American empire of the past.
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Частини книг з теми "Critical Flow Regime"

1

Thangadurai, Murugan, Mrityunjay Singh, Vinoth Kumar, and P. K. Chatterjee. "Effect of Free Stream Turbulence on Flow over a Circular Cylinder in the Sub-critical Regime: An Experimental Investigation." In Fluid Mechanics and Fluid Power – Contemporary Research, 1253–62. New Delhi: Springer India, 2016. http://dx.doi.org/10.1007/978-81-322-2743-4_119.

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Barsky, Eugene. "Principal Statistical Relations of Mass Transfer in Critical Flow." In Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase, 93–105. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8838-3_5.

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3

Barsky, Eugene. "Critical Regimes of Two-Phase Flows in Complicated Systems." In Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase, 215–64. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8838-3_11.

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Barsky, Eugene. "Stochastic Model of Critical Regimes of Two-Phase Flows." In Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase, 265–86. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8838-3_12.

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Barsky, Eugene. "Mass Transfer in Critical Regimes of Two-Phase Flows." In Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase, 287–331. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8838-3_13.

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6

Barsky, Eugene. "General Ideas of Mass Transfer Processes in Critical Regimes." In Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase, 1–17. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8838-3_1.

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7

Barsky, Eugene. "Stability and Kinetic Aspects of Mass Distribution in Critical Regimes." In Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase, 197–214. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8838-3_10.

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8

Barsky, Eugene. "System of Particles of the Same Size Class in a Critical Flow." In Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase, 33–57. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8838-3_3.

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9

Barsky, Eugene. "Structural Model of Mass Transfer in Critical Regimes of Two-Phase Flows." In Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase, 125–52. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8838-3_7.

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10

Barsky, Eugene. "Universal Curves Criteria." In Critical Regimes of Two-Phase Flows with a Polydisperse Solid Phase, 333–44. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8838-3_14.

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Тези доповідей конференцій з теми "Critical Flow Regime"

1

Cheng, W., D. I. Pullin, and Ravi Samtaney. "Large-eddy simulation of flow over a circular cylinder in the sub-critical regime." In Tenth International Symposium on Turbulence and Shear Flow Phenomena. Connecticut: Begellhouse, 2017. http://dx.doi.org/10.1615/tsfp10.1200.

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2

Bower, Jason S., and James F. Klausner. "Effect of Flow Orientation on Critical Heat Flux in Subcooled Flow Boiling." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56554.

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Recent work has demonstrated that as the bulk convective velocity in subcooled nucleate flow boiling increases, the heat transfer tends to become independent of flow orientation with respect to gravity. There is significant interest in developing heat exchangers for next generation spacecraft that operate in the gravity-independent flow boiling regime. In order to develop such heat exchangers it is important to understand the effect of gravity on the critical heat flux and to determine whether a gravity on the critical heat flux and to determine whether a gravity-independent flow boiling critical heat flux regime exists. This work describes subcooled flow boiling experiments where the critical heat flux is measured over a range of flow orientations with respect to gravity: 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°. It has been found that at low bulk flow velocities there is a large variation of critical heat flux with different flow orientations. At large convective velocities, the variation of critical heat flux with different flow orientations is significantly diminished. It appears that with further increases in bulk flow velocity, a gravity-independent critical heat flux regime exists, although the current experimental facility was not capable of operating at those flow conditions.
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3

Endo, Takahide, and Ryutaro Himeno. "NUMERICAL SIMULATION OF FLOW ACROSS A COMPLIANT BLUFF BODY IN THE CRITICAL REYNOLDS NUMBER REGIME." In Fourth International Symposium on Turbulence and Shear Flow Phenomena. Connecticut: Begellhouse, 2005. http://dx.doi.org/10.1615/tsfp4.880.

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4

Ota, Terukazu, Ken-ichiro Ueda, and Hiroyuki Yoshikawa. "Hysteresis of Flow Around an Elliptic Cylinder in Critical Reynolds Number Regime." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56141.

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Experimental investigations of the flow around an elliptic cylinder of axis ratio 1:2 were carried out for several angles of attack in a wide range of Reynolds number. The flow characteristics were studied by measuring the fluid forces and the surface pressure. In the critical Reynolds number regime, a discontinuous change of flow state was observed. This change was accompanied by the remarkable hysteresis phenomenon. The fluctuation of fluid forces and surface pressure, in general, markedly decreases in the critical flow state.
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Ota, Terukazu, Seijiro Takahashi, and Hiroyuki Yoshikawa. "Hysteresis of Flow Around an Elliptic Cylinder in Critical Reynolds Number Regime." In ASME 2005 Fluids Engineering Division Summer Meeting. ASMEDC, 2005. http://dx.doi.org/10.1115/fedsm2005-77236.

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Experimental investigations of the flow around an elliptic cylinder of axis ratio 1:3 were carried out for several angles of attack in a wide range of Reynolds number. The flow characteristics were studied by measuring the fluid forces and the surface pressure. In the critical Reynolds number regime, a discontinuous change of flow state was observed. This change was accompanied by the remarkable hysteresis phenomenon. Details of this hysteresis process are described in the paper.
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6

Gupta, Pradeep, Srisha Rao MV, and Pramod Kumar. "Effect of Mixing Duct Geometry of Supersonic Ejector in the Critical Flow Regime." In Proceedings of the 32nd International Symposium on Shock Waves (ISSW32 2019). Singapore: Research Publishing Services, 2019. http://dx.doi.org/10.3850/978-981-11-2730-4_0152-cd.

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7

Dabirian, Ramin, Ram S. Mohan, Ovadia Shoham, and Gene Kouba. "Sand Flow Regimes in Slightly Upward Inclined Gas-Liquid Stratified Flow." In ASME 2016 Fluids Engineering Division Summer Meeting collocated with the ASME 2016 Heat Transfer Summer Conference and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fedsm2016-7729.

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Sand particles are produced from the reservoir with low formation strength. A sand management system is required to be designed to keep the sand particles moving so as to prevent them from accumulating in the pipeline. Operating under unnecessarily high fluid velocities is not cost effective, moreover, it can lead to equipment failure; therefore, it is required to find the minimum velocity, known as critical sand deposition velocity, to keep the particles constantly moving. In order to assess the critical sand deposition condition, a unique test facility was designed and constructed with 4-in ID PVC pipeline, which enables the pipe to be inclined 1.5° upward. Experiments were conducted with air-water-glass beads at low sand concentrations (< 10,000 ppm), and the air and water flow rates were selected to ensure stratified flow regime along the pipe. At constant superficial liquid velocity the gas velocity was reduced to find the critical sand deposition velocity. The experimental results reveal that air-water flow regime plays an important role in particle transport; slug flow has high capability to transport particles at the pipe bottom, while the stratified flow has high risk of sand deposition. As long as the sand dunes are observed at the pipe bottom, the critical sand deposition velocities slightly increase with concentrations, while for stationary bed, the critical velocity increases exponentially with concentration.
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8

de With, Govert, Arne E. Holdo̸, and Thomas A. Huld. "Modeling of Flow Around a Circular Cylinder in Sub-Critical Flow Regime With the Use of Dynamic Grid Adaptation." In ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1457.

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In the present study a Dynamic Grid Adaptation (DGA) algorithm is used for predicting flow around a circular cylinder in sub-critical flow regime at a Reynolds number of 1.4·105. The reason for adopting a DGA algorithm is to use the flow field as a driving criteria for mesh refinement rather then the geometry of the computational domain or the judgment of the CFD user as common in conventional mesh. It is demonstrated how DGA reduces the mesh size significantly and also makes time consuming mesh testing unnecessary. The concept being adopted is to concentrate mesh refinement in regions with high gradients and high turbulent viscosity, while in the region further downstream where the flow is fully developed a coarser mesh will develop and turbulence is modeled with the Large Eddy Simulation (LES) turbulence model. The aim of the study is to present an appropriate variable for mesh refinement, which accomplishes a high rate of mesh refinement in the region with high gradients. The new variable is a product of the local mesh cell size and the rate of strain and includes two additional variables to allow control over the refinement behaviour.
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9

Zhao, Huizhe, Aydin Nabovati, and Cristina H. Amon. "Analysis of Fluid Flow in Porous Media Using the Lattice Boltzmann Method: Inertial Flow Regime." In ASME 2012 Fluids Engineering Division Summer Meeting collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fedsm2012-72127.

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In this work, we use the lattice Boltzmann method to study inertial flow in three-dimensional random fibrous porous materials. In order to validate the methodology, inertial flow in two-dimensional hexagonal arrangements of circular cylinders is simulated, and the results are compared against those previously reported in the literature. The three-dimensional fibrous porous materials are then constructed by randomly placing straight cylindrical fibers inside the computational domain. Inertial effects are studied systematically for a wide range of pore Reynolds numbers in materials with porosities between 0.60 and 0.95. A previously proposed semi-empirical relation is modified to represent the inertial effects in three-dimensional fibrous materials. Three distinct regimes of constant, quadratic, and linear relations between the inverse of the permeability and pore Reynolds number are observed for both two- and three-dimensional simulations. The critical Reynolds number, beyond which the inertial effects are strong and this relation is linear, is shown to be smaller in three-dimensional simulations, when compared to the critical Reynolds number in two-dimensional simulations.
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10

Bailey, C. L. "A Critical Review Of The Drag Force On A Sphere In The Transition Flow Regime." In RAREFIED GAS DYNAMICS: 24th International Symposium on Rarefied Gas Dynamics. AIP, 2005. http://dx.doi.org/10.1063/1.1941624.

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Звіти організацій з теми "Critical Flow Regime"

1

Nguyen, Hung. DTPH56-14-H-CAAP02 Wall Break-Through in Composite Repaired Defects. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), March 2017. http://dx.doi.org/10.55274/r0011839.

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Composite materials installed on pipelines where damage generated by corrosion or erosion that begins as a wall-loss defect that can transition to a through-wall defect. Critically, the damage generated by the process tends to have a region of diffuse wall loss surrounding a through-wall penetration. Design qualification of repairs for through-wall defects are performed using simulated flaws manufactured by drilling through the pipe wall. This creates straight-sided flaws with significant remaining stiffness, very different from the diffuse, tapered flaws produced by erosion or corrosion. This study will investigate the performance of composite repairs installed on drilled defects and diffuse flaws generated by an erosion process. Two different geometries, a 6 in diameter straight vessel and a 4 in diameter long radius elbow, are studied in this work. Finite element analysis is performed to help understand the influence of the shape and size of the damaged region on repair performance. Hydrostatic pressure testing of damaged and repaired test specimens is performed and the failure pressures of repairs installed on drilled and diffuse flaws are compared. Digital image correlation is performed to understand the development of strains in the repair and to provide a quantitative comparison between the two flaw types.
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2

Huntley, D., D. Rotheram-Clarke, R. Cocking, J. Joseph, and P. Bobrowsky. Current research on slow-moving landslides in the Thompson River valley, British Columbia (IMOU 5170 annual report). Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/331175.

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Interdepartmental Memorandum of Understanding (IMOU) 5170 between Natural Resources Canada (NRCAN), the Geological Survey of Canada (GSC) and Transport Canada Innovation Centre (TC-IC) aims to gain new insight into slow-moving landslides, and the influence of climate change, through testing conventional and emerging monitoring technologies. IMOU 5107 focuses on strategically important sections of the national railway network in the Thompson River valley, British Columbia (BC), and the Assiniboine River valley along the borders of Manitoba (MN) and Saskatchewan (SK). Results of this research are applicable elsewhere in Canada (e.g., the urban-rural-industrial landscapes of the Okanagan Valley, BC), and around the world where slow-moving landslides and climate change are adversely affecting critical socio-economic infrastructure. Open File 8931 outlines landslide mapping and changedetection monitoring protocols based on the successes of IMOU 5170 and ICL-IPL Project 202 in BC. In this region, ice sheets, glaciers, permafrost, rivers and oceans, high relief, and biogeoclimatic characteristics contribute to produce distinctive rapid and slow-moving landslide assemblages that have the potential to impact railway infrastructure and operations. Bedrock and drift-covered slopes along the transportation corridors are prone to mass wasting when favourable conditions exist. In high-relief mountainous areas, rapidly moving landslides include rock and debris avalanches, rock and debris falls, debris flows and torrents, and lahars. In areas with moderate to low relief, rapid to slow mass movements include rockslides and slumps, debris or earth slides and slumps, and earth flows. Slow-moving landslides include rock glaciers, rock and soil creep, solifluction, and lateral spreads in bedrock and surficial deposits. Research efforts lead to a better understanding of how geological conditions, extreme weather events and climate change influence landslide activity along the national railway corridor. Combining field-based landslide investigation with multi-year geospatial and in-situ time-series monitoring leads to a more resilient railway national transportation network able to meet Canada's future socioeconomic needs, while ensuring protection of the environment and resource-based communities from landslides related to extreme weather events and climate change. InSAR only measures displacement in the east-west orientation, whereas UAV and RTK-GNSS change-detection surveys capture full displacement vectors. RTK-GNSS do not provide spatial coverage, whereas InSAR and UAV surveys do. In addition, InSAR and UAV photogrammetry cannot map underwater, whereas boat-mounted bathymetric surveys reveal information on channel morphology and riverbed composition. Remote sensing datasets, consolidated in a geographic information system, capture the spatial relationships between landslide distribution and specific terrain features, at-risk infrastructure, and the environmental conditions expected to correlate with landslide incidence and magnitude. Reliable real-time monitoring solutions for critical railway infrastructure (e.g., ballast, tracks, retaining walls, tunnels, and bridges) able to withstand the harsh environmental conditions of Canada are highlighted. The provision of fundamental geoscience and baseline geospatial monitoring allows stakeholders to develop robust risk tolerance, remediation, and mitigation strategies to maintain the resilience and accessibility of critical transportation infrastructure, while also protecting the natural environment, community stakeholders, and Canadian economy. We propose a best-practice solution involving three levels of investigation to describe the form and function of the wide range of rapid and slow-moving landslides occurring across Canada that is also applicable elsewhere. Research activities for 2022 to 2025 are presented by way of conclusion.
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