Abstract: [1] The South China Sea throughflow begins at the Luzon Strait, as an intrusion of the Kuroshio. At the present time, there are insufficient in situ measurements either to estimate accurately the transport loss or to provide a clear picture of the Kuroshio pathway at the Luzon Strait. In this study, we use newly available, multi-year, high-resolution satellite images and a numerical model to track the warm, relatively low-biomass, Pacific water carried by the Kuroshio. A suite of numerical experiments are carried out to identify key factors that influence Kuroshio paths at the Luzon Strait. The model can reproduce the satellite-inferred Kuroshio paths across the Luzon Strait only when a significant amount of the Kuroshio water is allowed to enter the Luzon Strait during December–February, therefore providing strong evidence for the existence of the South China Sea throughflow.

Abstract: This paper investigates penetrative convection in a layer of porous material saturated with water when there is throughflow present. The density is quadratic in temperature. A linearized instability analysis is derived and compared with a weighted non-linear energy stability analysis. A weighted analysis is necessary to achieve a global non-linear stability threshold. Parameter ranges are found where the linear instability boundary is close to the non-linear stability one.

Abstract: Linear stability theory is used to investigate convective instability in a horizontal porous layer saturated with viscoelastic fluid of Oldroyd-B type in the presence of vertical throughflow. The flow in the porous medium is modelled using a modified Forchheimer–extended Darcy equation for viscoelastic fluids which takes into account the non-Darcy effects of inertia. The Galerkin method is used to obtain the eigenvalues under different hydrodynamic and temperature boundary conditions. The analysis reveals that there is competition between the processes of viscous relaxation and thermal diffusion that causes the first convective instability to be oscillatory rather than stationary. It is established that the oscillatory convection occurs only if Λ, the ratio of retardation time to relaxation time, is less than unity and the elasticity parameter Γ exceeds a threshold value which increases with throughflow strength. The effect of throughflow is to suppress the oscillatory convection independent of its direction when the velocity boundary conditions at the bounding surfaces of the porous layer are of the same type. In contrast to this, throughflow in one particular direction augments oscillatory convection if the velocity boundary conditions are not of the same type. It is observed that a decrease in the value of Γ and an increase in the value of Λ is found to delay the onset of convection, while the critical wavenumber decreases with both increasing Γ and Λ.

Abstract: Linear and nonlinear stability analyses of vertical throughflow in a fluid saturated porous layer, which is modelled using a cubic Forchheimer model, are studied. To ensure unconditional nonlinear results are obtainable, and to avoid the loss of key terms, a weighted functional is used in the energy analysis. The linear instability and nonlinear stability thresholds show considerable agreement when the vertical throughflow is small, although there is substantial deterioration of this agreement as the vertical throughflow increases.

Abstract: This contribution is dedicated to the modeling of the end-wall flows in a throughflow model for turbomachinery applications. The throughflow model is based on the Euler or Navier-Stokes equations solved by a Finite-Volume technique. Two approaches are presented for the end-wall modeling. The first one is based on an inviscid formulation with dedicated 3-D distributions of loss coefficient and deviation in the end-wall regions. The second approach is directly based on a viscous formulation with no-slip boundary condition along the annular end-walls and blade force modification in the region close to the end-walls. The throughflow results are compared to a series of 3-D Navier-Stokes calculations averaged in the circumferential direction. These 3-D calculations were performed on the three rotors of a low pressure axial compressor, for a series of tip clearance values.

Abstract: Two model simulations were performed to address the influence of the Indonesian throughflow (ITF) on the biogeochemical state of the equatorial Pacific. A simulation where the ITF is open is compared with an experiment where it is closed, and it is first shown that the impacts on the physical circulation are consistent with what has been found in previous modelling studies. In terms of biochemistry, closing the ITF results in increased iron concentration at the origin of the Equatorial Undercurrent (EUC). But the 11Sv of water otherwise transferred to the Indian Ocean remain in the equatorial Pacific, which result in a 30 m deepening of the thermocline/ferricline in the eastern Pacific. This deepening decreases the iron concentration of the equatorial wind driven upwelled water and cancels the iron increase advected by the EUC. The iron decrease of the equatorial upwelled water leads to decrease primary production by 15% along the equator.

Abstract: Throughflow analysis is a critical component for the multi-stage axial turbomachine design. The Euler throughflow approach has been developed over the last couple of decades, but has been less successful than its early peer, the streamline curvature approach. In this paper an Euler throughflow approach is described for engineering applications. It includes the steps needed to construct the stream surface, such as modifications for the incidence and deviation, and the throat area correction. The flow angle difference at the trailing edge and in the downstream non-bladed gap stations is resolved, and the numerical loss from solving the Euler equation is removed as well. This solver has been integrated into a comprehensive turbomachinery design system. It creates and modifies the machine geometries and predicts the machine performance at different levels of approximation, including one-dimensional design and analysis, quasi-three-dimensional methods (blade-to-blade and throughflow) and full-three-dimensional steady-state CFD analysis. The flow injection and extraction functions are described, as is the implementation of the radial mass distribution. Some discussion is dedicated to the shock calculation. Finally, examples are provided to demonstrate the pros and cons of the Euler throughflow approach and also to demonstrate the potential to solve for a wider range of flow conditions, particularly choked and transonic flows that limit stream function based solvers.Copyright © 2007 by Concepts ETI, Inc.

Abstract: The present study deals with the numerical simulation of the Indonesian throughflow (ITF) via three major passages, namely Lombok strait (115°E, 8°S), Savu strait (122°E, 9°S) and Timor strait (128°E, 11°S), its seasonal variability and impact on the sea surface parameters due to its blockage. The model is initialized with the Levitus94 climatological dataset for annual mean temperature and salinity fields, and is forced by the seasonal and yearly varying da Silva SMD 1994 and Hellerman and Rosenstein wind datasets. The spin-up of the model has been carried out separately for open and closed Indonesian channels using both the surface wind climatologies. Numerical simulations confirm that the ITF is mainly towards Indian Ocean in a year. It has been observed that surface winds have an impact on the phase as well as magnitude of the ITF. The net effect of blockage is reduction in temperature of the Southern Indian Ocean and no significant change is seen in surface salinity.

Abstract: A device for charge-air cooling for an internal combustion engine ( 13 ) of a motor vehicle, having at least one first heat exchanger ( 9 ) for charge-air cooling with at least one first flow duct ( 7 ) for a throughflow of a first medium which is to be cooled, with at least one second flow duct ( 8 ) for a throughflow of first medium which is substantially not to be cooled, and with at least two third flow ducts ( 6 ) for a throughflow of a coolant and/or refrigerant, having at least one housing ( 2 ) for holding the at least one first heat exchanger ( 9 ), wherein at least one regulating device ( 4 ) for temperature regulation and uniform temperature mixture of the first medium after flowing through the first heat exchanger ( 9 ) is provided.

Abstract: The variability of the Indonesian throughflow(ITF) and the South China Sea throughflow(that is indicated by the Luzon Strait transport,hereafter is LST) is analyzed by the "Island Rule" theory and the Simple Ocean Data Assimilation(SODA) data set.The results show that the volume transport of the LST(herein,LSTT) increased and that of the ITF(herein,ITFT) decreased after 1976.The main factors for the increase of the LSTT after 1976 include the easterly wind component in the east of the Luzon Strait and the local forcing of the northerly wind component in the interior SCS,and the contribution of the northerly wind anomaly component in the interior SCS can reach to 53%;while the westerly wind component in the equatorial Pacific is the main factor for the decrease of the ITF,with a contribution of 61%.The volume transport of the North Equatorial Current(NEC) near 15°N increased abnormally but the total NEC decreased abnormally after 1976.The volume transport of the Kuroshio Current(KC) increased abnormally,whereas those of the Mindanao Current(MC),the North Equatorial Countercurrent(NECC) and the South Equatorial Current (SEC) decreased abnormally.The cyclonic circulation anomaly in the western equatorial Pacific induced by the wind stress through the Sverdrup dynamic process obstructed the water flow from the Pacific Ocean to the Indian Ocean.

Abstract: A valve arrangement is proposed which has a plurality of valve batteries (1c) which are designed for different nominal throughflow rates. Each valve battery (1c) comprises a valve carrier (2) which is fitted with valve units (4), wherein the valve units (4) have in each case one control part (13) which is connected via electrical interface means (23) to internal signal transmission means (22) of the valve carrier (2). Irrespective of the throughflow category, the overall height of the valve carriers (2), the width of the fitting places and the valve units (4), and also the electrical interface means (23) are of identical configuration in the valve batteries of all throughflow categories. The nominal throughflow rates are varied, in particular, by the selection of different overall lengths of the valve units (4).

Abstract: A prototype clutch having horizontal rotational axis and a narrow gap between its two parallel radial disks is examined using computational fluid dynamics (CFD). The narrow gap between the discs is filled with an unexcited electrostructured fluid (ESF); the throughflow of electrorheological (ERF) or magnetorheological (MRF) fluid that would arise is contemplated as a means of contributing towards the cooling of the clutch. The throughflow, caused by body/centrifugal force action, is examined first when both plates rotate together at a speed, Ω. The aim is to estimate the flow rates arising under conditions of different rotational velocities, clutch geometries, and fluid properties. Following this, the cooling of the clutch is examined for the case of one plate fixed and the other rotating at a constant speed throughout. The inlet and outlet port pressures are made the same and the fluid is taken to be unexcited/Newtonian with viscosity μ.

Abstract: This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig. Measurements of heat transfer from the discs and tangential velocities are presented. The test rig is a 70 % full scale version of a high pressure compressor stack of an axial gas turbine engine. Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air. Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows (Re up to 5 million and Rez up to 200000). Two different builds have been tested. The most significant difference between these two build configurations is the size of the annular gap between the (non-rotating) drive shaft and the bores of the discs. The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method. The velocity measurements were made using a two component, LDA system. The heat transfer results from the discs show differences between the two builds. This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity. There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig. For the narrow annular gap, there is an increase of non-dimensional tangential velocity V / r with radial location to solid body rotation V / r = 1. For the wider annular gap, the non-dimensional velocities show a decrease with radial location to solid body rotation.

Abstract: The onset of Marangoni convection in a horizontal Oldroyd-B fluid layer in the presence of a vertical throughflow is determined by linear analysis. We find an approximate solution to the corresponding eigenvalue problem using the Galerkin method. The effects of viscoelastic parameters on the critical Marangoni number, wave number, and frequency are discussed. The study also reveals the existence of a critical retardation time for which the oscillatory motion reaches its maximum strength. This study has possible implications in microgravity situations. PACS No.: 47.20.Gv

Abstract: The invention relates to a suction jet pump ( 8 ), consisting of a driving jet nozzle ( 10 ), a mixing tube ( 11 ), an intake opening ( 12 ), a working-fluid line ( 7 ) connected to the driving jet nozzle ( 10 ), and a valve ( 9 ) which is arranged with the working-fluid line ( 7 ) and whose housing ( 13 ) has an inlet ( 14 ) and an outlet ( 15 ). A throughflow opening ( 17 ) with a valve body ( 18 ) on both sides of the throughflow opening ( 17 ) is arranged in the housing ( 13 ) in such a way that the throughflow opening ( 17 ) can be closed on both the inlet side and the outlet side, and that at least one spring ( 25, 27, 28 ) is arranged inside the housing ( 13 ) in such a way that it holds the valve body ( 18 ) in a position closing the throughflow opening ( 17 ) on the outlet side until the system pressure is reached.

Abstract: Using outputs from the SINTEX-F1 coupled GCM, the thermodynamics of ENSO events and its relation with the seasonal cycle are investigated. Simulated El Nino events are first classified into four groups depending on during which season the Nino-3.4 sea surface temperature anomaly (SSTA) index (5°S–5°N, 120°–170°W) reaches its peak. Although the heat content of the tropical Pacific decreases for all four types, the tropical Pacific loses about twice as much during an El Nino that peaks during winter compared with one that peaks during summer. The surface heat flux, the southward heat transport at 15°S, and the Indonesian Throughflow heat transport contribute constructively to this remarkable seasonal difference. It is shown that the Indonesian Throughflow supplies anomalous heat from the Indian Ocean, especially during the summer El Nino–like event. Changes in the basic state provided by the seasonal cycle cause differences in the atmospheric response to the SSTA, which in turn lead to the difference between the surface heat flux and the meridional heat transport anomaly.

Abstract: A new method for measuring the throughflow velocity crossing the dome of erupting bubbles in freely bubbling 2-D fluidized beds is presented. Using a high speed videocamera, the dome acceleration, drag force and throughflow velocity profiles are obtained for different experiments, varying the superficial gas velocity. The acceleration profiles show greater values in the dome zone where the gravity component is negligible. The drag force and the throughflow velocity profiles show a uniform value in the central region of the dome (40 deg < θ < 140 deg) and the total throughflow increases with the superficial gas velocity.

Abstract: The role of vorticity dynamics in the axial compressor diagnosis and design is investigated analytically and numerically, in terms of the stagnation-pressure flux that controls the compressor’s performance. The stagnation-pressure flux is found to be dominated by the distribution of circumferential vorticity. The circumferential vorticity is directly expressible by the circulation distribution which is the significant parameter in the throughflow compressor design. Some principles of controlling compressor performance are thereby proposed, which are demonstrated by two rotor blades, designed by throughflow procedure and evaluated by three-dimensional Reynolds-average Navier-Stokes simulation.Copyright © 2007 by ASME

Abstract: High precision direct numerical simulations (DNS) of the boundary layer flow in a rotating cavity are carried above the expected critical Reynolds number for transition from convective to absolute behaviour. The sustained presence of an absolute mode of crossflow instabilty is observed, associated with saturation and progressive spectrum broadening, due to non-linear effects. Eventually, the flow settles in a solution exhibiting properties consistent with a global non-linear mode.

Abstract: The invention relates to a numerical method and associated device for optimizing a throughflow behavior of a flowing fluid, while generating an adjustable cylinder internal flow, utilizing a determination of a swirl intensity of the fluid flowing into a cylinder of a direct-injection four-stroke internal combustion engine when the intake valve is open, for facilitating an optimization of a throughflow behavior and of a cylinder internal flow of a fluid flowing into a reciprocating-piston internal combustion engine, and in particular for improving the quality of the optimization, wherein a numerical map of at least surfaces of the cylinder which delimit the inflowing fluid at least in the cylinder is generated and utilized, and by means of a computer model, a numerical flow simulation of the inflowing fluid when the intake valve is open is carried out taking into consideration thermodynamic boundary conditions, wherein the computer model is based on a cylindrical coordinate system in which a Z axis of the computer model coincides with a cylinder axis, and the swirl intensity is determined from the ratio of at least one tangential speed component, determined in relation to the Z axis, of the flow of the inflowing fluid during its rotation through a disk-shaped or annular volume in the cylinder to a determined second speed.

Abstract: The 3D pathways of the Indonesian Throughflow (ITF) in the Indian Ocean are identified using an OGCM, with a combined set of tools: 1) Lagrangian particle trajectories, 2) passive tracers, and 3) active tracers (temperature and salinity). Each of these tools has its own advantages and limitations to represent the watermass pathways. The Lagrangian particles, without horizontal and vertical mixing, suggest that at the entrance region the surface ITF subducts along the northwestern coast of Australia and then travels across the Indian Ocean along the thermocline depths. The subsurface ITF more directly departs westward and crosses the Indian Ocean. Using the passive tracers, which are mixed vertically under convection as well as horizontally due to diffusion, the ITF is shown to undergo vigorous mixing as soon as it enters the Indian Ocean and modifies its upper temperature–salinity (T–S) characteristics. Thus, the surface and subsurface ITF watermasses lose their identities. Upon reaching the west...

Abstract: This paper presents an optimization method for fan/compressor which couples throughflow model solving axisymmetric Euler equations with adaptive simulated annealing (ASA) algorithm. One of the advantages of this optimization method is that it spends much less time than 3D optimization due to the rapid solving of throughflow model. In addition, the optimization space is quite extensive because more design variables can be adjusted in throughflow phase, such as swirl distribution, hub curve and sweep. To validate this optimization method, a highly loaded fan rotor with pressure ratio of 3.06 as a baseline is optimized. During the optimization process, the objective function is total pressure ratio, moreover, mass flow and efficiency are selected as the constraint conditions. Three important design variables including swirl distribution, hub curve and sweep are parameterized using Bezier curve, and then optimized in throughflow model independently, finally the optimum designs are validated using 3D viscous CFD solver. It is shown that pressure ratio and rotor loading can be improved further through optimizing swirl distribution, however, hub and sweep curves take more effects on mass flow and efficiency respectively. The optimization results demonstrate the advantage and feasibility of this optimization method.Copyright © 2007 by ASME