Articles de revues : « Throughflow model »

1

Yang, Chen, Hu Wu, Jinguang Yang et Michele Ferlauto. « Time-marching throughflow analysis of multistage axial compressors based on a novel inviscid blade force model ». Proceedings of the Institution of Mechanical Engineers, Part G : Journal of Aerospace Engineering 233, n^o 14 (avril 2019) : 5239–52. http://dx.doi.org/10.1177/0954410019840588.

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A time-marching throughflow method for the off-design performance analysis of axial compressors is described. The method is based on the Euler equations, and a new inviscid blade force model is proposed in order to achieve desired flow deflection. The flow discontinuity problems at the leading and trailing edges are tackled by automatic correction of blade mean surface using cubic spline interpolation. Empirical loss models have been integrated into the throughflow model in order to simulate the viscous force effects in the real three-dimensional flow. Two test cases have been presented to validate the throughflow model, including the transonic fan rotor – NASA Rotor 67 working at a near-peak-efficiency point and a 1.5-stage high-speed axial compressor with inlet guide vane operating at 68% nominal speed. Reasonable flow parameters distributions have been obtained in the Rotor 67 fan calculating results, and accurate overall performance characteristics have also been predicted at the strong off-design condition for the 1.5-stage axial compressor. The CPU time of both cases cost less than one minute at one operating point. The results indicate that the developed time-marching throughflow model is effective and efficient in the turbomachinery performance analysis.

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Yang, Chen, Juan Du, Hongwu Zhang, Hu Wu, Qing Tang et Jinguang Yang. « Time-Marching Throughflow Analysis of Centrifugal Compressors with Boundary Conditions Based on Newton’s Method ». Applied Sciences 12, n^o 13 (29 juin 2022) : 6576. http://dx.doi.org/10.3390/app12136576.

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The meridional distribution of the flow parameters inside the centrifugal compressor is of great importance to its overall performance, as well as its matching performance under a thermal cycle. A time-marching throughflow method for the off-design performance analysis of the centrifugal compressor is described. The method is based on the strictly conservative throughflow-governing equations, and an improved method of boundary-condition enforcement is developed based on Newton’s method to achieve a robust and fast throughflow simulation. An inviscid blade force model was adopted to obtain the flow deflection inside the blade passage. Empirical loss models were integrated into the throughflow model to simulate the viscous force effects in the real three-dimensional flow. Two test cases are presented to validate the throughflow method by comparisons with the experimental data or CFD results, including the NASA low-speed centrifugal compressor (LSCC) and the Allison high-performance centrifugal compressor (HPCC). The simulation indicated that the developed enforcement method for the inlet and outlet boundary conditions significantly improves the computational robustness. For both the LSCC and HPCC cases, reasonable flow-parameter distribution was obtained and accurate overall characteristics were also predicted under the off-design conditions. The results indicated that the developed time-marching throughflow method is effective and efficient for the performance analysis of centrifugal compressors.

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Howard, M. A., et S. J. Gallimore. « Viscous Throughflow Modeling for Multistage Compressor Design ». Journal of Turbomachinery 115, n^o 2 (1 avril 1993) : 296–304. http://dx.doi.org/10.1115/1.2929235.

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An existing throughflow method for axial compressors, which accounts for the effects of spanwise mixing using a turbulent diffusion model, has been extended to include the viscous shear force on the endwall. The use of a shear force, consistent with a no-slip condition, on the annulus walls in the throughflow calculations allows realistic predictions of the velocity and flow angle profiles near the endwalls. The annulus wall boundary layers are therefore incorporated directly into the throughflow prediction. This eliminates the need for empirical blockage factors or independent annulus boundary layer calculations. The axisymmetric prediction can be further refined by specifying realistic spanwise variations of loss coefficient and deviation to model the three-dimensional endwall effects. The resulting throughflow calculation gives realistic predictions of flow properties across the whole span of a compressor. This is confirmed by comparison with measured data from both low and high-speed multistage machines. The viscous throughflow method has been incorporated into an axial compressor design system. The method predicts the meridional velocity defects in the endwall region and consequently blading can be designed that allows for the increased incidence, and low dynamic head, near the annulus walls.

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Hamm, A., H. Remeth et N. Schilling. « Ecosystem model for a lake with high throughflow ». SIL Proceedings, 1922-2010 23, n^o 2 (août 1988) : 796–800. http://dx.doi.org/10.1080/03680770.1987.11899716.

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Schneider, Niklas, et Tim P. Barnett. « Indonesian throughflow in a coupled general circulation model ». Journal of Geophysical Research : Oceans 102, n^o C6 (15 juin 1997) : 12341–58. http://dx.doi.org/10.1029/97jc00022.

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Feng, Xue, HaiLong Liu, FuChang Wang, YongQiang Yu et DongLiang Yuan. « Indonesian Throughflow in an eddy-resolving ocean model ». Chinese Science Bulletin 58, n^o 35 (26 juillet 2013) : 4504–14. http://dx.doi.org/10.1007/s11434-013-5988-7.

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Wei, Jun, M. T. Li, P. Malanotte-Rizzoli, A. L. Gordon et D. X. Wang. « Opposite Variability of Indonesian Throughflow and South China Sea Throughflow in the Sulawesi Sea ». Journal of Physical Oceanography 46, n^o 10 (octobre 2016) : 3165–80. http://dx.doi.org/10.1175/jpo-d-16-0132.1.

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AbstractBased on a high-resolution (0.1° × 0.1°) regional ocean model covering the entire northern Pacific, this study investigated the seasonal and interannual variability of the Indonesian Throughflow (ITF) and the South China Sea Throughflow (SCSTF) as well as their interactions in the Sulawesi Sea. The model efficiency in simulating the general circulations of the western Pacific boundary currents and the ITF/SCSTF through the major Indonesian seas/straits was first validated against the International Nusantara Stratification and Transport (INSTANT) data, the OFES reanalysis, and results from previous studies. The model simulations of 2004–12 were then analyzed, corresponding to the period of the INSTANT program. The results showed that, derived from the North Equatorial Current (NEC)–Mindanao Current (MC)–Kuroshio variability, the Luzon–Mindoro–Sibutu flow and the Mindanao–Sulawesi flow demonstrate opposite variability before flowing into the Sulawesi Sea. Although the total transport of the Mindanao–Sulawesi flow is much larger than that of the Luzon–Mindoro–Sibutu flow, their variability amplitudes are comparable but out of phase and therefore counteract each other in the Sulawesi Sea. Budget analysis of the two major inflows revealed that the Luzon–Mindoro–Sibutu flow is enhanced southward during winter months and El Niño years, when more Kuroshio water intrudes into the SCS. This flow brings more buoyant SCS water into the western Sulawesi Sea through the Sibutu Strait, building up a west-to-east pressure head anomaly against the Mindanao–Sulawesi inflow and therefore resulting in a reduced outflow into the Makassar Strait. The situation is reversed in the summer months and La Niña years, and this process is shown to be more crucially important to modulate the Makassar ITF’s interannual variability than the Luzon–Karimata flow that is primarily driven by seasonal monsoons.

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Humphries, U. W., et D. J. Webb. « On the Indonesian Throughflow in the OCCAM 1/4 degree ocean model ». Ocean Science 4, n^o 3 (28 juillet 2008) : 183–98. http://dx.doi.org/10.5194/os-4-183-2008.

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Abstract. The Indonesian Throughflow is analysed in two runs of the OCCAM 1/4 degree global ocean model, one using monthly climatological winds and one using ECMWF analysed six-hourly winds for the period 1993 to 1998. The long-term model throughflow agrees with observations and the value predicted by Godfrey's Island Rule. The Island Rule has some skill in predicting the annual signal each year but is poor at predicting year to year and shorter term variations in the total flow, especially in El Niño years. The spectra of transports in individual passages show significant differences between those connecting the region to the Pacific Ocean and those connecting with the Indian Ocean. On investigation we found that changes in the northern transports were strongly correlated with changes in the position of currents in the Celebes Sea and off Halmahera. Vertical profiles of transport are in reasonable agreement with observations but the model overestimates the near surface transport through the Lombok Strait and the dense overflow from the Pacific through the Lifamatola Strait into the deep Banda Sea. In both cases the crude representation of the passages by the model appears responsible. In the north the model shows, as expected, that the largest transport is via the Makassar Strait. However this is less than expected and instead there is significant flow via the Halmahera Sea. If Godfrey's Island Rule is correct and the throughflow is forced by the northward flow between Australia and South America, then the Halmahers Sea route should be important. It is the most southerly route around New Guinea to the Indian Ocean and there is no apparent reason why the flow should go further north in order to pass through the Makassar Strait. The model result thus raises the question of why in reality the Makassar Strait route appears to dominate the throughflow.

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Humphries, U. W., et D. J. Webb. « On the Indonesian throughflow in the OCCAM 1/4 degree ocean model ». Ocean Science Discussions 4, n^o 2 (21 mars 2007) : 325–70. http://dx.doi.org/10.5194/osd-4-325-2007.

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Abstract. The Indonesian Throughflow is analysed in two runs of the OCCAM 1/4 degree global ocean model, one using monthly climatological winds and one using ECMWF analysed six-hourly winds for the period 1993 to 1998. The long-term model throughflow agrees with observations and the value predicted by Godfrey's Island Rule. The Island Rule has some skill in predicting the annual signal each year but is poor at predicting year to year and shorter term variations in the total flow especially in El Nino years. The spectra of transports in individual passages show significant differences between those connecting the region to the Pacific Ocean and those connecting with the Indian Ocean. This implies that different sets of waves are involved in the two regions. Vertical profiles of transport are in reasonable agreement with observations but the model overestimates the near surface transport through the Lombok Strait and the dense overflow from the Pacific through the Lifamatola Strait into the deep Banda Sea. In both cases the crude representation of the passages by the model appears responsible. In the north the model shows, as expected, that the largest transport is via the Makassar Strait. However this is less than expected and instead there is significant flow via the Halmahera Sea. If Godfrey's Island Rule is correct and the throughflow is forced by the northward flow between Australia and South America, then the Halmahers Sea route should be important. It is the most southerly route around New Guinea to the Indian Ocean and there is no apparent reason why the flow should go further north in order to pass through the Makassar Strait. The model result thus raises the question of why in reality the Makassar Strait route appears to dominate the throughflow.

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Smith, Nils Solheim, Ganesh H. R. Ravindra et Fjóla Guðrún Sigtryggsdóttir. « Numerical Modeling of the Effects of Toe Configuration on Throughflow in Rockfill Dams ». Water 13, n^o 13 (22 juin 2021) : 1726. http://dx.doi.org/10.3390/w13131726.

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The rockfill toe structure situated within the downstream slope of rockfill dams is an integral part of a defense mechanism safeguarding the dam structure in throughflow situations. Recent studies have concluded that the rockfill toe structure can have significant impacts on throughflow development and stability of rockfill dams under scenarios of accidental throughflow caused by overtopping of the dam core. The ability to numerically model the effect of various toe configurations on flow through rockfill dams can support the design of effective toe drainage structures for rockfill dams. Development and calibration of a reliable numerical modeling tool in this regard has been challenging owing to lack of availability of extensive datasets from physical modeling investigations. This study further employs datasets gathered by a recent physical modeling study investigating the effects of various toe configurations on throughflow development in rockfill dam models. A commercial numerical seepage modeling tool with an option for non-Darcy flow was calibrated against the datasets with good calibration metrics. The study is novel in providing a rare report on the usage of this option. The calibrated tool can further be employed to carry out a wide array of simulations to arrive at an ideal design for a toe structure for rockfill dams and for assessment of hydraulic performance of toe structures.

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Le Bars, D., H. A. Dijkstra et W. P. M. De Ruijter. « Impact of the Indonesian throughflow on Agulhas leakage ». Ocean Science Discussions 10, n^o 1 (19 février 2013) : 353–91. http://dx.doi.org/10.5194/osd-10-353-2013.

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Abstract. Using ocean models of different complexity we show that opening the Indonesian Passage between the Pacific and the Indian Ocean increases the input of Indian Ocean water into the South Atlantic via the Agulhas leakage. In a strongly eddying global ocean model this response results from an increased Agulhas Current transport and a constant proportion of Agulhas retroflection south of Africa. The leakage increases through an increased frequency of ring shedding events. In an idealized two-layer and flat-bottom eddy resolving model, the proportion of the Agulhas Current transport that retroflects is (for a wide range of wind stress forcing) not affected by an opening of the Indonesian Passage. A linear ocean model is not able to explain this behavior which reveals the importance of mixed barotropic/baroclinic instabilities in controlling the Agulhas leakage.

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Le Bars, D., H. A. Dijkstra et W. P. M. De Ruijter. « Impact of the Indonesian Throughflow on Agulhas leakage ». Ocean Science 9, n^o 5 (5 septembre 2013) : 773–85. http://dx.doi.org/10.5194/os-9-773-2013.

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Abstract. Using ocean models of different complexity we show that opening the Indonesian Passage between the Pacific and the Indian oceans increases the input of Indian Ocean water into the South Atlantic via the Agulhas leakage. In a strongly eddying global ocean model this response results from an increased Agulhas Current transport and a constant proportion of Agulhas retroflection south of Africa. The leakage increases through an increased frequency of ring shedding events. In an idealized two-layer and flat-bottom eddy resolving model, the proportion of the Agulhas Current transport that retroflects is (for a wide range of wind stress forcing) not affected by an opening of the Indonesian Passage. Using a comparison with a linear model and previous work on the retroflection problem, the result is explained as a balance between two mechanisms: decrease retroflection due to large-scale momentum balance and increase due to local barotropic/baroclinic instabilities.

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Van den Braembussche, R. A., et B. M. Ha¨nde. « Experimental and Theoretical Study of the Swirling Flow in Centrifugal Compressor Volutes ». Journal of Turbomachinery 112, n^o 1 (1 janvier 1990) : 38–43. http://dx.doi.org/10.1115/1.2927418.

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Measurements of the three-dimensional flow in a simplified model of a centrifugal compressor volute at design and off-design operation are presented. A nearly constant swirl velocity is observed near the walls and a forced vortex type of flow is observed in the center. This velocity distribution is almost identical at all cross sections and all operating points. An explanation is given on how this swirl distribution results from the specific way a volute is filled with fluid. The throughflow velocity component shows a large crosswise variation. A minimum or maximum velocity is observed at the volute center depending on the operating point. A simple analytic model, based on the radial equilibrium of forces, is described. Calculations for isentropic flows reveal the relation between the swirl distribution and the large increase of throughflow velocity toward the center. This explains why volutes should be designed with negative blockage. Nonisentropic calculations, using the experimental loss distribution, correctly reproduce the measured throughflow velocity and static pressure distribution.

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Dunham, J. « A New Endwall Model for Axial Compressor Throughflow Calculations ». Journal of Turbomachinery 117, n^o 4 (1 octobre 1995) : 533–40. http://dx.doi.org/10.1115/1.2836565.

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It is well recognized that the endwall regions of a compressor—in which the annulus wall flow interacts with the mainstream flow—have a major influence on its efficiency and surge margin. Despite many attempts over the years to predict the very complex flow patterns in the endwall regions, current compressor design methods still rely largely on empirical estimates of the aerodynamic losses and flow angle deviations in these regions. This paper describes a new phenomenological model of the key endwall flow phenomena treated in a circumferentially averaged way. It starts from Hirsch and de Ruyck’s annulus wall boundary layer approach, but makes some important changes. The secondary vorticities arising from passage secondary flows and from tip clearance flows are calculated. Then the radial interchanges of momentum, energy, and entropy arising from both diffusion and convection are estimated. The model is incorporated into a streamline curvature program. The empirical blade force defect terms in the boundary layers are selected from cascade data. The effectiveness of the method is illustrated by comparing the predictions with experimental results on both low-speed and high-speed multistage compressors. It is found that the radial variation of flow parameters is quite well predicted, and so is the overall performance, except when significant endwall stall occurs.

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Song, Panpan, Ding Wu, Zhenbo Lu, Siyu Zheng, Mingshan Wei, Weilin Zhuge et Yangjun Zhang. « An Improved Geometric Theoretical Model and Throughflow Prediction Method for a CO2 Scroll Compressor of Automotive Air Conditioning System ». International Journal of Energy Research 2023 (6 février 2023) : 1–18. http://dx.doi.org/10.1155/2023/9382690.

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The scroll-type compressor is the core component of the refrigeration system using the natural refrigerant carbon dioxide. An accurate scroll geometric theoretical model is essential for evaluating and enhancing compressor performance. The present paper proposed and validated an improved geometric theoretical model of a scroll compressor. A vector triangle method-based general piecewise function describes precisely the volume variation of the working chambers, based on which the transient throughflow modeling and performance evaluation of a carbon dioxide scroll compressor were conducted. The mechanisms and influencing factors of the suction precompression and the asymmetry discharging were analyzed. The results indicate that the strength of the suction precompression is mainly influenced by the suction vacuum under different rotating speeds, partly associated with the tangential leakage under low rotating speeds. The increasing initial suction pressure contributes to the linear raising of the pressure difference between suction initial and ending pressures, decreasing the precompression extension slightly. The variation of the discharge throughflow areas of two symmetric discharge chambers dominates the pressure asymmetry, which is gradually eliminated by the overlapping throughflow area. Compared with the circular discharge structure, the waist-shape port reduces the pressure asymmetry degree and shortens its duration.

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Yadav, Dhananjay. « The effect of pulsating throughflow on the onset of magneto convection in a layer of nanofluid confined within a Hele-Shaw cell ». Proceedings of the Institution of Mechanical Engineers, Part E : Journal of Process Mechanical Engineering 233, n^o 5 (13 mars 2019) : 1074–85. http://dx.doi.org/10.1177/0954408919836362.

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In this article, the joint effect of pulsating throughflow and magnetic field on the onset of convective instability in a nanofluid layer, bounded in a Hele-Shaw cell is presented within the context of linear stability theory and frozen profile approach. The model utilized for nanofluid combines the impacts of Brownian motion and thermophoresis, while for Hele-Shaw cell, Hele-Shaw model is considered. The Galerkin technique is utilized to solve the eigenvalue problem. The outcome of the important parameters on the stability framework is examined analytically. It is observed that the pulsating throughflow and magnetic field have both stabilizing effects. The impact of increasing the Hele-Shaw number [Formula: see text], the modified diffusive ratio [Formula: see text] and the nanoparticle Rayleigh number [Formula: see text] is to quicken the convective motion, while the Lewis number [Formula: see text] has dual impact on the stability framework in the existence of pulsating throughflow. It is also established that the oscillatory mode of convective motion is possible only when the value of the magnetic Prandtl number [Formula: see text] is not greater than unity.

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Sravan Nayeka Gaikwad et Preeti Bhushan Rangdal. « Effect of Gravity and Throughflow on Double Diffusive Convection in a Couple Stress Fluid Saturated Porous Media ». Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 101, n^o 1 (18 janvier 2023) : 121–36. http://dx.doi.org/10.37934/arfmts.101.1.121136.

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We have investigated effect of throughflow and gravity modulation on double diffusive convection with couple-stress fluid saturated porous media. Applying the Landau model, we have derived finite amplitude of couple-stress convection in the presence of gravity modulation. The presence of a couple-stress parameter produces both diminishing and enhancing heat mass transfer in the layer. To present the results we have used Mathematica to obtain the Nusselt number and Sherwood numbers numerically. Further, it is shown that, throughflow and modulation of gravity controls double diffusive convection through convective amplitude and alter transport phenomenon.

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Lewis, K. L. « Spanwise Transport in Axial-Flow Turbines : Part 1—The Multistage Environment ». Journal of Turbomachinery 116, n^o 2 (1 avril 1994) : 179–86. http://dx.doi.org/10.1115/1.2928351.

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Selected experimental results, obtained from a detailed investigation into the flow fields within two low-speed multistage turbines, are presented. A repeating stage condition occurred typically after two stages, with the secondary flows an important factor in the low aspect ratio geometry. A tracer gas technique was employed to identify the dominant mechanisms of spanwise transport and their relative significance. In the first stages of both machines, tracer transport was more intense near the endwalls than at midspan, while in the multistage environment the transport was approximately constant across the whole span. The convective influence of classical secondary flow, shroud leakage, and wake passage through a downstream blade was identified and shown to be as significant as turbulent diffusion in effecting cross-passage and spanwise transport. The data show that spanwise transport should be included within any throughflow model and are used to calibrate two scaling models. These models are presented in Part 2, where the influence of incorporating spanwise transport into a throughflow model is investigated.

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Potemra, James T., Susan L. Hautala et Janet Sprintall. « Vertical structure of Indonesian throughflow in a large-scale model ». Deep Sea Research Part II : Topical Studies in Oceanography 50, n^o 12-13 (juillet 2003) : 2143–61. http://dx.doi.org/10.1016/s0967-0645(03)00050-x.

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Wajsowicz, Roxana C. « A Simple Model of the Indonesian Throughflow and Its Composition ». Journal of Physical Oceanography 23, n^o 12 (décembre 1993) : 2683–703. http://dx.doi.org/10.1175/1520-0485(1993)023<2683:asmoti>2.0.co;2.

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Lewis, K. L. « Spanwise Transport in Axial-Flow Turbines : Part 2—Throughflow Calculations Including Spanwise Transport ». Journal of Turbomachinery 116, n^o 2 (1 avril 1994) : 187–93. http://dx.doi.org/10.1115/1.2928352.

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In Part 1 of this paper, a repeating stage condition was shown to occur in two low aspect ratio turbines, typically after two stages. Both turbulent diffusion and convective mechanisms were responsible for spanwise transport. In this part, two scaling expressions are determined that account for the influence of these mechanisms in effecting spanwise transport. These are incorporated into a throughflow model using a diffusive term. The inclusion of spanwise transport allows the use of more realistic loss distributions by the designer as input to the throughflow model and therefore focuses attention on areas where losses are generated. In addition, modeling of spanwise transport is shown to be crucial in predicting the attenuation of a temperature profile through a turbine.

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Aldrian, Edvin, et Jon Arifian. « PREDICTION OF SOUTHERN OSCILLATION USING THE INDONESIAN THROUGHFLOW VARIABILITY ». Marine Research in Indonesia 34, n^o 1 (30 juin 2009) : 1–9. http://dx.doi.org/10.14203/mri.v34i1.516.

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Atmospheric boundary layer derived from NCEP/NCAR reanalyses for the period of 1974 to 2002 has been used as boundary forcings for the global ocean model Max Planck Institute Ocean Model (MPIOM). The ocean model is a curvilinear grid model, whose poles are located over mainland China and over the Australian continent, thus focusing on the maritime continent. The model simulates major Indonesian throughflow passages that focus on six cannels representing three inlets and three outlets (the Makassar, Lifamatola, Halmahera, Lombok, Ombai and Timor Straits). The model results have been validated using the Arlindo observation Project over the Makassar Strait in the period of January 1997 to February 1998, which fortunately was during a strong El Niño episode. The model simulation results were then investigated for their prediction capabilities of any of those channels in foreseeing the incoming southern oscillation events. Temporal correlation analysis with lag and advance time correlation methods were performed against simulated data at all levels on those channels. Variabilities in depth of 74 to 200m (thermocline depth) show the strongest correlation with SOI index (Darwin minus Tahiti mean sea level pressure). The temperature and salinity correlations with SOI are the highest with one-month in advance over Lifamatola Strait (0.77) and two-month in advance over the Makassar Straits (0.74). These significant correlations highlight the important of those two straits in prediction of incoming southern oscillation that usually leads to ENSO episode which brings most of the time devastating impact to economy, agriculture and ecosystem.

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Shinoda, Toshiaki, Weiqing Han, E. Joseph Metzger et Harley E. Hurlburt. « Seasonal Variation of the Indonesian Throughflow in Makassar Strait ». Journal of Physical Oceanography 42, n^o 7 (1 juillet 2012) : 1099–123. http://dx.doi.org/10.1175/jpo-d-11-0120.1.

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Abstract The seasonal variation of Indonesian Throughflow (ITF) transport is investigated using ocean general circulation model experiments with the Hybrid Coordinate Ocean Model (HYCOM). Twenty-eight years (1981–2008) of ⅓° Indo-Pacific basin HYCOM simulations and three years (2004–06) from a global HYCOM simulation are analyzed. Both models are able to simulate the seasonal variation of upper-ocean currents and the total transport through Makassar Strait measured by International Nusantara Stratification and Transport (INSTANT) moorings reasonably well. The annual cycle of upper-ocean currents is then calculated from the Indo-Pacific HYCOM simulation. The reduction of southward currents at Makassar Strait during April–May and October–November is evident, consistent with the INSTANT observations. Analysis of the upper-ocean currents suggests that the reduction in ITF transport during April–May and October–November results from the wind variation in the tropical Indian Ocean through the generation of a Wyrtki jet and the propagation of coastal Kelvin waves, while the subsequent recovery during January–March originates from upper-ocean variability associated with annual Rossby waves in the Pacific that are enhanced by western Pacific winds. These processes are also found in the global HYCOM simulation during the period of the INSTANT observations. The model experiments forced with annual-mean climatological wind stress in the Pacific and 3-day mean wind stress in the Indian Ocean show the reduction of southward currents at Makassar Strait during October–November but no subsequent recovery during January–March, confirming the relative importance of wind variations in the Pacific and Indian Oceans for the ITF transport in each season.

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Gaikwad SN, Preeti Bhushan et P Kiran. « Effects of Throughflow and Gravity Modulation on Thermal Convection in a Couple Stress Fluid Saturated Porous Layer ». CFD Letters 14, n^o 7 (17 juillet 2022) : 1–17. http://dx.doi.org/10.37934/cfdl.14.7.117.

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In this paper, we have investigated the effects of throughflow and gravity modulation on a couple stress fluid saturated porous layer using non-autonomous Ginzburg-Landau model. A small variation of disturbances has been considered to examine the nonlinear thermal instability in a couple stress fluid saturated porous media. At third order, the finite amplitude of convection has been calculated which determines heat transfer. The effect of throughflow i.e., inflow and outflow have dual nature of heat transfer. The couple-stress parameter has stabilizing nature on thermal instability. The couple-stress parameter has stabilizing nature on thermal instability. Further it is found that upward directed flow enhances and downward directed flow diminishes heat transfer.

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Polat, S., A. S. Mujumdar, A. R. P. van Heiningen et W. J. M. Douglas. « Numerical model for turbulent jets impinging on a surface with throughflow ». Journal of Thermophysics and Heat Transfer 5, n^o 2 (avril 1991) : 172–80. http://dx.doi.org/10.2514/3.245.

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Jin, Hailiang, Daobin Qiu et Yueqian Yin. « A Novel Viscous Throughflow Model for Compressor Analysis and Its Application ». International Journal of Fluid Mechanics & ; Thermal Sciences 6, n^o 3 (2020) : 89. http://dx.doi.org/10.11648/j.ijfmts.20200603.13.

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Yaremchuk, Max, Julian McCreary, Zuojun Yu et Ryo Furue. « The South China Sea Throughflow Retrieved from Climatological Data* ». Journal of Physical Oceanography 39, n^o 3 (1 mars 2009) : 753–67. http://dx.doi.org/10.1175/2008jpo3955.1.

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Abstract The salinity distribution in the South China Sea (SCS) has a pronounced subsurface maximum from 150–220 m throughout the year. This feature can only be maintained by the existence of a mean flow through the SCS, consisting of a net inflow of salty North Pacific tropical water through the Luzon Strait and outflow through the Mindoro, Karimata, and Taiwan Straits. Using an inverse modeling approach, the authors show that the magnitude and space–time variations of the SCS thermohaline structure, particularly for the salinity maximum, allow a quantitative estimate of the SCS throughflow and its distribution among the three outflow straits. Results from the inversion are compared with available observations and output from a 50-yr simulation of a highly resolved ocean general circulation model. The annual-mean Luzon Strait transport is found to be 2.4 ± 0.6 Sv (Sv ≡ 106 m3 s−1). This inflow is balanced by the outflows from the Karimata (0.3 ± 0.5 Sv), Mindoro (1.5 ± 0.4), and Taiwan (0.6 ± 0.5 Sv) Straits. Results of the inversion suggest that the Karimata transport tends to be overestimated in numerical models. The Mindoro Strait provides the only passage from the SCS deeper than 100 m, and half of the SCS throughflow (1.2 ± 0.3 Sv) exits the basin below 100 m in the Mindoro Strait, a result that is consistent with a climatological run of a 0.1° global ocean general circulation model.

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Kajtar, Jules B., Agus Santoso, Matthew H. England et Wenju Cai. « Indo-Pacific Climate Interactions in the Absence of an Indonesian Throughflow ». Journal of Climate 28, n^o 13 (1 juillet 2015) : 5017–29. http://dx.doi.org/10.1175/jcli-d-14-00114.1.

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Abstract The Pacific and Indian Oceans are connected by an oceanic passage called the Indonesian Throughflow (ITF). In this setting, modes of climate variability over the two oceanic basins interact. El Niño–Southern Oscillation (ENSO) events generate sea surface temperature anomalies (SSTAs) over the Indian Ocean that, in turn, influence ENSO evolution. This raises the question as to whether Indo-Pacific feedback interactions would still occur in a climate system without an Indonesian Throughflow. This issue is investigated here for the first time using a coupled climate model with a blocked Indonesian gateway and a series of partially decoupled experiments in which air–sea interactions over each ocean basin are in turn suppressed. Closing the Indonesian Throughflow significantly alters the mean climate state over the Pacific and Indian Oceans. The Pacific Ocean retains an ENSO-like variability, but it is shifted eastward. In contrast, the Indian Ocean dipole and the Indian Ocean basinwide mode both collapse into a single dominant and drastically transformed mode. While the relationship between ENSO and the altered Indian Ocean mode is weaker than that when the ITF is open, the decoupled experiments reveal a damping effect exerted between the two modes. Despite the weaker Indian Ocean SSTAs and the increased distance between these and the core of ENSO SSTAs, the interbasin interactions remain. This suggests that the atmospheric bridge is a robust element of the Indo-Pacific climate system, linking the Indian and Pacific Oceans even in the absence of an Indonesian Throughflow.

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Yu, Kai, et Tangdong Qu. « Imprint of the Pacific Decadal Oscillation on the South China Sea Throughflow Variability* ». Journal of Climate 26, n^o 24 (2 décembre 2013) : 9797–805. http://dx.doi.org/10.1175/jcli-d-12-00785.1.

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Abstract Analysis of the 62-yr hindcast outputs from an eddy-resolving ocean general circulation model reveals a prominent decadal variability in the upper-layer (0–745 m) Luzon Strait transport (LST), a key component of the South China Sea throughflow. This variability is in phase with the basin-scale wind stress anomalies associated with the Pacific decadal oscillation (PDO). A composite analysis shows that during the positive phase of the PDO, the Aleutian low and its related positive wind stress curl anomalies intrude southward, reducing the trade winds and enhancing the westerly wind anomalies in the tropical North Pacific. In response, the North Equatorial Current bifurcation shifts northward, resulting in a weaker Kuroshio east of Luzon and consequently a stronger South China Sea throughflow in the upper 745 m.

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Magrini, Andrea. « Body Force Model Implementation of Transonic Rotor for Fan/Airframe Simulations ». Aerospace 9, n^o 11 (18 novembre 2022) : 725. http://dx.doi.org/10.3390/aerospace9110725.

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Three-dimensional throughflow models represent a turbomachinery cascade via a force distribution without the need for detailed geometric modelling in the numerical solution, saving consistent computational resources. In this paper, we present the application of a body force method on an axial transonic fan implemented into an in-house tool for axisymmetric throughflow simulations. By a systematic comparison of local and integral quantities with a validated numerical solution, the capabilities and limitations of the model are discussed for different operating regimes. The implementation is first validated at the peak efficiency calibration point, providing a good duplication of blade flow variables and radial profiles. The design total pressure is matched with a 0.6% absolute difference and a slightly higher slope of the characteristic towards the stall. The isentropic efficiency curve is penalised after the choking mass flow rate calibration, presenting an absolute difference close to 2%, although with a consistent off-design trend. In general, the model provides a satisfactory representation of the flow field and the outflow spanwise distributions, with locally larger discrepancies near the endwalls. Finally, the method is applied to simulate the fan and outlet guide vanes installed into an isolated turbofan nacelle. The onset of intake stall at a high angle of attack is compared between the body force and a boundary conditions-based approaches, highlighting the importance of adopting fully coupled solution methods to study fan/airframe interaction problems.

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Ribbe, Joachim, et Matthias Tomczak. « Effect of the Missing Indonesian Throughflow in the Fine Resolution Antarctic Model ». Journal of Physical Oceanography 27, n^o 3 (mars 1997) : 445–55. http://dx.doi.org/10.1175/1520-0485(1997)027<0445:eotmit>2.0.co;2.

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Goosse, H., J. M. Campin, T. Fichefet et E. Deleersnijder. « Sensitivity of a global ice-ocean model to the Bering Strait throughflow ». Climate Dynamics 13, n^o 5 (20 juillet 1997) : 349–58. http://dx.doi.org/10.1007/s003820050170.

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Masumoto, Yukio, et Toshio Yamagata. « Seasonal variations of the Indonesian throughflow in a general ocean circulation model ». Journal of Geophysical Research : Oceans 101, n^o C5 (15 mai 1996) : 12287–93. http://dx.doi.org/10.1029/95jc03870.

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Jin, Hai-liang, Dong-hai Jin, Xiao-juan Li et Xing-min Gui. « A time-marching throughflow model and its application in transonic axial compressor ». Journal of Thermal Science 19, n^o 6 (décembre 2010) : 519–25. http://dx.doi.org/10.1007/s11630-010-0418-5.

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Zhou, Lei, Raghu Murtugudde et Markus Jochum. « Seasonal Influence of Indonesian Throughflow in the Southwestern Indian Ocean ». Journal of Physical Oceanography 38, n^o 7 (1 juillet 2008) : 1529–41. http://dx.doi.org/10.1175/2007jpo3851.1.

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Abstract The influence of the Indonesian Throughflow (ITF) on the dynamics and the thermodynamics in the southwestern Indian Ocean (SWIO) is studied by analyzing a forced ocean model simulation for the Indo-Pacific region. The warm ITF waters reach the subsurface SWIO from August to early December, with a detectable influence on weakening the vertical stratification and reducing the stability of the water column. As a dynamical consequence, baroclinic instabilities and oceanic intraseasonal variabilities (OISVs) are enhanced. The temporal and spatial scales of the OISVs are determined by the ITF-modified stratification. Thermodynamically, the ITF waters influence the subtle balance between the stratification and the mixing in the SWIO. As a result, from October to early December an unusual warm entrainment occurs, and the SSTs warm faster than just net surface heat flux–driven warming. In late December and January, the signature of the ITF is seen as a relatively slower warming of SSTs. A conceptual model for the processes by which the ITF impacts the SWIO is proposed.

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Kida, Shinichiro, Bo Qiu, Jiayan Yang et Xiaopei Lin. « The Annual Cycle of the Japan Sea Throughflow ». Journal of Physical Oceanography 46, n^o 1 (janvier 2016) : 23–39. http://dx.doi.org/10.1175/jpo-d-15-0075.1.

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AbstractThe mechanism responsible for the annual cycle of the flow through the straits of the Japan Sea is investigated using a two-layer model. Observations show maximum throughflow from summer to fall and minimum in winter, occurring synchronously at the three major straits: Tsushima, Tsugaru, and Soya Straits. This study finds the subpolar winds located to the north of Japan as the leading forcing agent, which first affects the Soya Strait rather than the Tsushima or Tsugaru Straits. The subpolar winds generate baroclinic Kelvin waves along the coastlines of the subpolar gyre, affect the sea surface height at the Soya Strait, and modify the flow through the strait. This causes barotropic adjustment to occur inside the Japan Sea and thus affect the flow at the Tsugaru and Tsushima Straits almost synchronously. The barotropic adjustment mechanism explains well why the observations show a similar annual cycle at the three straits. The annual cycle at the Tsugaru Strait is further shown to be weaker than that in the other two straits based on frictional balance around islands, that is, frictional stresses exerted around an island integrate to zero. In the Tsugaru Strait, the flows induced by the frictional integrals around the northern (Hokkaido) and southern (Honshu) islands are in opposite directions and tend to cancel out. Frictional balance also suggests that the annual cycle at the Tsugaru Strait is likely in phase with that at the Soya Strait because the length scale of the northern island is much shorter than that of the southern island.

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Ou, Hsien-Wang. « A Model of Buoyant Throughflow : With Application to Branching of the Tsushima Current* ». Journal of Physical Oceanography 31, n^o 1 (janvier 2001) : 115–26. http://dx.doi.org/10.1175/1520-0485(2001)031<0115:amobtw>2.0.co;2.

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Manjula, S. H., et Palle Kiran. « Throughflow and Gravity Modulation Effects on Double Diffusive Oscillatory Convection in a Viscoelastic Fluid Saturated Porous Medium ». Advanced Science, Engineering and Medicine 12, n^o 5 (1 mai 2020) : 612–21. http://dx.doi.org/10.1166/asem.2020.2565.

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Weakly nonlinear stability analysis has been performed using the finite amplitude Ginzburg-Landau model. The layer is oscillating vertically in sinusoidal manner. Using the finite amplitude analysis heat mass/transfer is quantified in the system. The disturbances of the flow are expanded in power series of small parameter. In addition to the modulation, the effect of throughflow is discussed on heat/mass transfer in the system. The values of viscoelastic parameters are considered in this paper are λ1 > λ2 and Γ < 1 to validate the problem. The time relaxation parameter λ1 has destabilizing effect, while the time retardation parameter λ2 has stabilizing effect on the system. The effects of amplitude and frequency of modulation on heat/mass transports have been analyzed and depicted graphically. The studies establish that the heat/mass transports can be controlled effectively by g-jitter and throughflow. Further, it is found that better results may obtain for an oscillatory mode of convection.

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Gallimore, S. J. « Viscous Throughflow Modeling of Axial Compressor Bladerows Using a Tangential Blade Force Hypothesis ». Journal of Turbomachinery 120, n^o 4 (1 octobre 1998) : 662–70. http://dx.doi.org/10.1115/1.2841775.

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This paper describes the modeling of axial compressor blade rows in an axisymmetric viscous throughflow method. The basic method, which has been reported previously, includes the effects of spanwise mixing, using a turbulent diffusion model, and endwall shear within the throughflow calculation. The blades are modeled using a combination of existing two-dimensional blade performance predictions for loss and deviation away from the annulus walls and a novel approach using tangential blade forces in the endwall regions. Relatively simple assumptions about the behavior of the tangential static pressure force imposed by the blades allow the secondary deviations produced by tip clearance flows and the boundary layer flows at fixed blade ends to be calculated in the axisymmetric model. Additional losses are assigned in these regions based on the calculated deviations. The resulting method gives realistic radial distributions of loss and deviation across the whole span at both design and off-design operating conditions, providing a quick method of estimating the magnitudes of these effects in the preliminary design process. Results from the method are compared to measured data in low and high-speed compressors and multistage three-dimensional viscous CFD predictions.

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Chriss, R. M., M. D. Hathaway et J. R. Wood. « Experimental and Computational Results From the NASA Lewis Low-Speed Centrifugal Impeller at Design and Part-Flow Conditions ». Journal of Turbomachinery 118, n^o 1 (1 janvier 1996) : 55–65. http://dx.doi.org/10.1115/1.2836607.

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The NASA Lewis Low-Speed Centrifugal Compressor (LSCC) has been investigated with laser anemometry and computational analysis at two flow conditions: the design condition as well as a lower mass flow condition. Previously reported experimental and computational results at the design condition are in the literature (Hathaway et al., 1993). In that paper extensive analysis showed that inducer blade boundary layers are centrifuged outward and entrained into the tip clearance flow and hence contribute significantly to the throughflow wake. In this report results are presented for a lower mass flow condition along with further results from the design case. The data set contained herein consists of three-dimensional laser velocimeter results upstream, inside, and downstream of the impeller. In many locations data have been obtained in the blade and endwall boundary layers. The data are presented in the form of throughflow velocity contours as well as secondary flow vectors. The results reported herein illustrate the effects of flow rate on the development of the through flow momentum wake as well as on the secondary flow. The computational results presented confirm the ability of modern computational tools to model the complex flow in a subsonic centrifugal compressor accurately. However, the blade tip shape and tip clearance must be known in order to properly simulate the flow physics. In addition, the ability to predict changes in the throughflow wake, which is largely fed by the tip clearance flow, as the impeller is throttled should give designers much better confidence in using computational tools to improve impeller performance.

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Watts, L. G., et A. Calver. « Effects of Spatially-Distributed Rainfall on Runoff for a Conceptual Catchment ». Hydrology Research 22, n^o 1 (1 février 1991) : 1–14. http://dx.doi.org/10.2166/nh.1991.0001.

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A physically-based rainfall-runoff model is used to investigate effects of moving storms on the runoff hydrograph of throughflow dominated idealised catchments. Simulations are undertaken varying the storm speed, direction, intensity, the part of the catchment affected by rainfall, and the spatial definition of rainfall zones. For a 100 km2 catchment, under the circumstances investigated, an efficient spatial resolution of rainfall data is around 2.5 km along the path of the storm. Storms moving downstream produce earlier, higher peaks than do storms moving upstream. Error is most likely to be introduced into lumped-rainfall predictions for slower storm speeds, and the likely direction of this error can be specified. Differences in magnitude of peak response between downstream and upstream storm directions reach a maximum at a storm speed and direction similar to the average peak channel velocity. These results are qualitatively similar to those reported for overland flow dominated catchments, but differences in peak runoff between downstream and upstream storm directions are much smaller where rainfall inputs are modified by a period of hillslope throughflow.

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Yang, Wen-Jei, Nengli Zhang et Jeff Chiou. « Local Heat Transfer in a Rotating Serpentine Flow Passage ». Journal of Heat Transfer 114, n^o 2 (1 mai 1992) : 354–61. http://dx.doi.org/10.1115/1.2911283.

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An experimental study is performed on the internal cooling of a rotating serpentine flow passage of square cross section with throughflow. The test section is not proceeded by a hydrodynamic calming region, i.e., a leading arm, and is rotated at low Rossby numbers. The local heat transfer coefficients along the flow passage, including the leading wall, trailing wall, and sidewalls, are determined together with the circumferentially averaged values. The Reynolds, Rossby, and rotating Rayleigh numbers are varied to determine their effects on heat transfer performance. It is disclosed that heat transfer augmentation is significant at all sharp turns due to the presence of strong secondary flow. The rotational effect is very obvious and complicated in the local heat transfer performance but it is very minor on the average heat transfer performance. The throughflow rate plays an important role on the heat transfer performance. The results may serve as a baseline for comparison with the results from a model with a leading arm to determine the effects of a hydrodynamic calming section on the heat transfer performance of a rotating serpentine flow passage.

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Sturmayr, A., et Ch Hirsch. « Throughflow model for design and analysis integrated in a three-dimensional Navier-Stokes solver ». Proceedings of the Institution of Mechanical Engineers, Part A : Journal of Power and Energy 213, n^o 4 (juin 1999) : 263–73. http://dx.doi.org/10.1243/0957650991537608.

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Godfrey, J. S., et Y. Masumoto. « Diagnosing the mean strength of the Indonesian Throughflow in an ocean general circulation model ». Journal of Geophysical Research : Oceans 104, n^o C4 (15 avril 1999) : 7889–95. http://dx.doi.org/10.1029/1998jc900108.

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Santoso, A., W. Cai, M. H. England et S. J. Phipps. « The Role of the Indonesian Throughflow on ENSO Dynamics in a Coupled Climate Model ». Journal of Climate 24, n^o 3 (1 février 2011) : 585–601. http://dx.doi.org/10.1175/2010jcli3745.1.

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Abstract The effects of the Indonesian Throughflow (ITF) on ENSO dynamics are studied in a coupled climate model by comparing two simulations, one with an open ITF and the other with a closed ITF. Closing the ITF results in an El Niño–like climate state in the Pacific, which is characterized by weakened trade winds, a flatter equatorial thermocline, and weaker equatorial upwelling. A weakened South Equatorial Current allows the western Pacific warm pool to extend eastward, thereby reducing the zonal temperature gradient along the equator. The interdecadal component of the ENSO-like variability collapses, although the interannual variability is maintained. The core region of the ENSO SST anomalies becomes confined farther east. This results from Bjerknes feedback processes that are shifted eastward. This study conducts an analysis utilizing the Bjerknes coupled stability index as formulated by Jin et al. and finds that the relative importance of the thermocline feedback is enhanced in the closed ITF experiment. This indicates a more prominent ENSO thermocline mode, thus explaining the existence of more prevalent eastward-propagating anomalies. A weaker zonal advective feedback due to the reduced mean zonal temperature gradient contributes to the dominance of the thermocline mode. The strength of the thermocline feedback itself is maintained by enhanced coupling between the zonal wind stress and the east–west thermocline slope. However, an increased thermal damping by air–sea heat flux dominates the overall ENSO feedback process.

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Komuro, Yoshiki, et Hiroyasu Hasumi. « Intensification of the Atlantic Deep Circulation by the Canadian Archipelago Throughflow ». Journal of Physical Oceanography 35, n^o 5 (1 mai 2005) : 775–89. http://dx.doi.org/10.1175/jpo2709.1.

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Abstract Low-salinity water export through the Canadian Archipelago is one of the main components of the freshwater budget in the Arctic Ocean. Nevertheless, the Canadian Archipelago is closed in most global ocean models. How it is that deep-water formation at high latitudes of the Northern Hemisphere depends on the opening and closing of the Canadian Archipelago is investigated. An ice–ocean coupled model, whose horizontal resolution is 1°, is used without restoring surface salinity to observed data. When the Canadian Archipelago is open, the Atlantic deep circulation strengthens by 21%. This enhancement is caused by intensification of deep-water formation in the northern North Atlantic Ocean. Surface salinity in these regions is affected by the East Greenland Current, which flows from the Fram Strait and increases its salinity when the Canadian Archipelago is opened. The low-salinity flow through the Canadian Archipelago affects surface salinity only in the western part of the Labrador Sea. A cyclonic circulation in the Labrador Sea plays an important role in limiting the direct impact of the Canadian Archipelago throughflow. Consequently, the deep-water formation there is intensified and the Atlantic deep circulation is strengthened. Thus, it is suggested that the Canadian Archipelago throughflow does not weaken the Atlantic deep circulation by the freshening of the Labrador Sea but strengthens it by the salinity increase in the Fram Strait.

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Lambert, E., D. Le Bars et W. P. M. de Ruijter. « The dynamic connection of the Indonesian Throughflow, South Indian Ocean Countercurrent and the Leeuwin Current ». Ocean Science Discussions 12, n^o 5 (25 septembre 2015) : 2231–56. http://dx.doi.org/10.5194/osd-12-2231-2015.

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Abstract. East of Madagascar, wind and surface buoyancy fluxes reinforce each other, leading to frontogenesis, outcrop and an eastward along-front flow: the South Indian Ocean Countercurrent (SICC). In the east the Leeuwin Current (LC) is a unique eastern boundary current which flows poleward along Australia. It is often described as a regional coastal current forced by an off-shore meridional density gradient or a sea surface slope, yet little is known of the forcing and dynamics that control these open ocean meridional gadients. To complete this understanding, we make use of both an ocean general circulation model and a conceptual two-layer model. The SICC impinges on west Australia and adds to a sea level slope and a southward geostrophic coastal jet: the Leeuwin Current. The SICC and the LC are thus dynamically connected. An observed transport maximum of the LC around 22° S is directly related to this impingement of the SICC. The circulation of the Indonesian Throughflow (ITF) through the Indian Ocean appears to be partly trapped in the upper layer north of the outcrop line and is redirected along this outcrop line to join the eastward flow of the SICC. Shutdown of the ITF in both models strongly decreases the Leeuwin Current transport and breaks the connection between the LC and SICC. In this case, most of the SICC was found to reconnect to the internal gyre circulation in the Indian Ocean. The Indonesian Throughflow, South Indian Ocean Countercurrent and the Leeuwin Current are thus dynamically coupled.

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Qu, Tangdong, Yan Du, Julian P. McCreary, Gary Meyers et Toshio Yamagata. « Buffering Effect and Its Related Ocean Dynamics in the Indonesian Throughflow Region* ». Journal of Physical Oceanography 38, n^o 2 (1 février 2008) : 503–16. http://dx.doi.org/10.1175/2007jpo3759.1.

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Abstract Analysis of results from a high-resolution general circulation model confirms the existence of a “buffering” effect in the Indo-Australian Basin in which the upper ocean receives an excess of water from February to June and releases it during the rest of the year. A similar, but significantly weaker, phenomenon exists in the Indonesian seas. The buffering mostly results from geostrophic convergence, with the directly wind-driven Ekman divergence playing a role only within the Indonesian seas. Upward phase propagation, or equivalently, downward energy propagation, is revealed, indicating the prominent influence of remotely forced Kelvin waves originating in the equatorial Indian Ocean. The model demonstrates that these Kelvin waves penetrate as far eastward as the Ombai Strait along the southern Indonesian coastal waveguide, and that they have a notable influence on the upper-ocean convergence/divergence in the Indo-Australian Basin. Some of the semiannual signal turns northward through the Lombok and Ombai Straits to impact the circulation and thermal structure within the Indonesian seas.

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Hu, Shijian, Ying Zhang, Ming Feng, Yan Du, Janet Sprintall, Fan Wang, Dunxin Hu, Qiang Xie et Fei Chai. « Interannual to Decadal Variability of Upper-Ocean Salinity in the Southern Indian Ocean and the Role of the Indonesian Throughflow ». Journal of Climate 32, n^o 19 (29 août 2019) : 6403–21. http://dx.doi.org/10.1175/jcli-d-19-0056.1.

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Abstract Variability of oceanic salinity, an indicator of the global hydrological cycle, plays an important role in the basin-scale ocean circulation. In this study, interannual to decadal variability of salinity in the upper layer of the Indian Ocean is investigated using Argo observations since 2004 and data assimilating model outputs (1992–2015). The southeastern Indian Ocean shows the strongest interannual to decadal variability of upper-ocean salinity in the Indian Ocean. Westward propagation of salinity anomalies along isopycnal surfaces is detected in the southern Indian Ocean and attributed to zonal salinity advection anomalies associated with the Indonesian Throughflow and the South Equatorial Current. Composite and salinity budget analyses show that horizontal advection is a major contributor to the interannual to decadal salinity variability of the southern Indian Ocean, and the local air–sea freshwater flux plays a secondary role. The Pacific decadal oscillation (PDO) and El Niño–Southern Oscillation (ENSO) modulate the salinity variability in the southeastern Indian Ocean, with low salinity anomalies occurring during the negative phases of the PDO and ENSO and high salinity anomalies during their positive phases. The Indonesian Throughflow plays an essential role in transmitting the PDO- and ENSO-related salinity signals into the Indian Ocean. A statistical model is proposed based on the PDO index, which successfully predicts the southeastern Indian Ocean salinity variability with a lead time of 10 months.

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Atmadipoera, Agus S., Selfrida M. Horhoruw, Mulia Purba et Dwi Y. Nugroho. « SPATIAL AND TEMPORAL VARIATION OF INDONESIAN THROUGHFLOW IN THE MAKASSAR STRAIT ». Jurnal Ilmu dan Teknologi Kelautan Tropis 8, n^o 1 (11 novembre 2016) : 299–320. http://dx.doi.org/10.29244/jitkt.v8i1.13221.

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Using outputs of INDESO model, this study investigated vertical structure, spatial and temporal variation of the Indonesian Throughflow in Makassar Strait (M-ITF). It was shown that the main axis of persistent southward jet of M-ITF formed a unique path following the western shelf slope along the strait, which was associated with a high kinetic energy (KE) region from near-surface down to the thermocline layer. Furthermore, a drastic jump of KE appeared in the narrow and deep Libani Chan-nel (near 3°S) where the strait's width shrinks significantly, thus an elevated flow velocity was needed to maintain transport volume balance. Here, maximum southward velocity at thermocline exceeded 1.2 m/s. Spatial pattern of M-ITF can be described by the first EOF mode which accounts for 79 % of the total variances. It exhibited that contours of the flow amplitudes were similar to M-ITF path, and the largest amplitude was located near the Libani Channel. Out-of-phase relationship of the flow was found between M-ITF and eddies circulation that developed in the edges of the strait. Corresponding temporal fluctuation of the first EOF mode indicated that M-ITF variabilities varied from intra-seasonal to inter-annual scales. Annual fluctuation of M-ITF was seen from EOF mode-2 (at thermocline layer) and mode-3 at lower-thermocline. Cross-spectra analysis revealed that variability of M- ITF (e.g. on annual scale) at northern entrance was highly coherent to the fluctuations of North Equatorial Current (NEC) and Mindanao Current (MC), suggesting that variability of M-ITF was remotely influenced by the Pacific low-latitude western boundary currents. Keywords: INDESO model, Indonesian Throughflow, Makassar Strait, EOF, Cross-Spectra Analysis

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