Abstract: [1] Variability of water mass and throughflow transport in the Taiwan Strait are analyzed using strait-wide conductivity-temperature-depth (1985–2003) and sectional acoustic Doppler current profiler (1999–2001) data. Results from a cluster analysis, temperature-salinity diagrams, and direct transport calculations indicate that the strong northeast monsoon drives the brackish Mixed China Coastal Water into the northern strait and hinders the northward intruded saline Kuroshio Branch Water (KBW) in the southeastern strait from December to January. The mean throughflow transport across the central strait is about 0.1 Sv southward during this period, thus supporting previous observations that there is no persistent northward flowing current throughout the strait in winter. The weakening of the northeast monsoon in February–March, however, emancipates the KBW to intrude northward into the East China Sea (ECS). In June, the increase in this northward transport accompanied by the decrease in the westward intrusion of Kuroshio through the Luzon Strait leads to the replacement of the KBW by the less saline South China Sea Water (SCSW). The northward transports ranging from 1.16 to 2.34 Sv between March and August yield 0.131–0.238 × 1015 W and 53.33–81.74 × 106 kg/s of temperature and salt transports, respectively, toward the ECS. The inception of the northeast monsoon in October marks both the change of water mass from fall to winter patterns and the decrease of the northward throughflow transport. Our results also reveal that the subsurface KBW and SCSW remain consistent throughout the observation periods between 100 and 200 m and below 200 m depths, respectively, in the southeastern strait.

Abstract: [ 1] We use a multiproxy approach to monitor changes in the vertical profile of the Indonesian Throughflow as well as monsoonal wind and precipitation patterns in the Timor Sea on glacial-interglacial, precessional, and suborbital timescales. We focus on an interval of extreme climate change and sea level variation: marine isotope (MIS) 6 to MIS 5e. Paleoproductivity fluctuations in the Timor Sea follow a precessional beat related to the intensity of the Australian (NW) monsoon. Paired Mg/Ca and delta(18)O measurements of surface- and thermocline-dwelling planktonic foraminifers ( G. ruber and P. obliquiloculata) indicate an increase of > 4 degrees C in both surface and thermocline water temperatures during Termination II. Tropical sea surface temperature changed synchronously with ice volume (benthic delta(18)O) during deglaciation, implying a direct coupling of high- and low-latitude climate via atmospheric and/or upper ocean circulation. Substantial cooling and freshening of thermocline waters occurred toward the end of Termination II and during MIS 5e, indicating a change in the vertical profile of the Indonesian Throughflow from surface- to thermocline-dominated flow.

Abstract: We present Nd isotopic data for fossil fish teeth recovered from the past 40 m.y. at ODP Site 757, currently located at 1650 m water depth on the Ninetyeast Ridge in the Indian Ocean. Although Site 757 sits in a region strongly influenced by weathering inputs from the Himalayas and volcanic inputs from the Indonesian arc, the pattern of Nd isotopic variations does not appear to respond to these potential sources of Nd. Instead, secular variations correlate to changes in the composition of intermediate to deep water masses bathing the site and circulation patterns in the Indian Ocean. From ∼40 to 10 Ma, ɛNd values and the pattern of change at Site 757 closely match those of ODP Site 1090, a deep water site in the Atlantic sector of the Southern Ocean. Comparison to data from several Fe-Mn crusts in the Indian Ocean suggests that intermediate to deep water flow paths were similar to the modern distribution of Circumpolar Deep Water. At approximately 10 Ma, Nd isotopic values increase in a step function by 2 ɛNd units, suggesting that plate motions had carried Site 757 into a region influenced by Indonesian Throughflow. Estimates of the vertical and horizontal position of this site at 10 Ma imply that Indonesian Throughflow extended as far south as ∼20°S and to a depth of ∼1500 m. From 10 to 0 Ma, Nd isotopic variations at Site 757 appear to record variations in Indonesian Throughflow. From 10 to 5.5 Ma, values at Site 757 overlap with those from crusts located in the southwest Pacific, indicating extensive flow through the Indonesian Seaway. From 5.5 to 3.4 Ma, ɛNd values become less radiogenic at Site 757 and more radiogenic in the southwest Pacific, suggesting increasing closure of the seaway and concomitant rerouting of equatorial Pacific waters. Beginning at 3.4 Ma, ɛNd values become more radiogenic again at Site 757, which may be attributed to enhanced opening of the seaway or to a change in the source of Throughflow waters from a southern to a northern Pacific region.

Abstract: Experimental measurements were made in a rotating-cavity rig with an axial throughflow of cooling air at the center of the cavity, simulating the conditions that occur between corotating compressor disks of a gas-turbine engine. One of the disks in the rig was heated, and the other rotating surfaces were quasi-adiabatic; the temperature difference between the heated disk and the cooling air was between 40 and 100°C. Tests were conducted for axial Reynolds numbers, Re z , of the cooling air between 1.4×10 3 and 5 X 10 4 , and for rotational Reynolds numbers, Re Φ , between 4 X 10 5 and 3.2 X 10 6 . Velocity measurements inside the rotating cavity were made using laser Doppler anemometry, and temperatures and heat flux measurements on the heated disk were made using thermocouples and fluxmeters. The velocity measurements were consistent with a three-dimensional, unsteady, buoyancy-induced flow in which there was a multicell structure comprising one, two, or three pairs of cyclonic and anticyclonic vortices. The core of fluid between the boundary layers on the disks rotated at a slower speed than the disks, as found by other experimenters. At the smaller values of Re z , the radial distribution and magnitude of the local Nusselt numbers, Nu, were consistent with buoyancy-induced flow. At the larger values of Re z , the distribution of Nu changed, and its magnitude increased, suggesting the dominance of the axial throughflow.

Abstract: The purpose of this paper is to investigate the effect of vertical throughflow on the onset of bioconvection in a suspension of gyrotactic microorganisms. A dilute suspension of gyrotactic microorganisms in a shallow system that consists of superimposed fluid and porous layers is considered. A linear instability analysis of this problem is performed and the Galerkin method is utilized to solve the eigenvalue problem. The analysis leads to an equation for the critical Rayleigh number. It is shown that the vertical throughflow stabilizes the system.

Abstract: In this paper we study gravitational instability of a saline boundary layer formed by evaporation induced upward throughflow at the horizontal surface of a porous medium. Van Duijn et al. [P.A.C. Raats, D. Smiles, and A.W. Warrick (Eds.), Environmental Mechanics – Water, Mass and Energy Transfer in the Biosphere – The Philip Volume, Geophys. Monographs, Vol. 129, American Geophysical Union, 2002, pp. 155–169], derived stability bounds by means of linear stability analysis and an (improved) energy method. These bounds do not coincide, i.e. there exists a subcritical region or stability gap in the system parameter space which is due to the asymmetry of the linear part of the perturbation equations. We show that the linear operator can be symmetrized by means of a similarity transformation. For system parameter values in the stability gap, we show that there exist initial perturbations for which the linearly stable system exhibits transient growth. We show that transient growth is norm dependent by considering weighted norms, which are induced by a one-parameter family of similarity transformations.

Abstract: Annular cavities are found inside rotor shafts of turbomachines with an axial or radial throughflow of cooling air, which influences the thermal efficiency and system reliability of the gas turbines. The flow and heat transfer phenomena in those cavities should be investigated in order to minimize the thermal load and guarantee system reliability. An experimental rig is set up in the Institute of Steam and Gas Turbines to analyze the flow structure inside the rotating cavity with an axial throughflow of cooling air. The corresponding 3D numerical investigation is carried out with the in-house fluid solver CHTflow, in which the Coriolis force and the buoyancy force are implemented in the time-dependent Navier-Stokes equations. Both the experimental and numerical results show the whole flow structure rotating against the cavity rotating direction. The flow passing the observation windows shows the quite similar trajectories in the experimental and numerical results. The computed sequences and periods of the vortex flow structure correspond closely with those observed in the experiment. Furthermore, the numerical analysis reveals a flow pattern changing between single pair, double pairs and triple pairs vortices. It is suggested that the vortices inside the cavity are created by the gravitational buoyancy force in the investigated case, and the number and strength of the vortices are controlled mainly by the Coriolis force.Copyright © 2006 by ASME

Abstract: A device for mixing the components of a mass flow flowing through the same provides a particularly homogenous mixture which remains stable for any length of time, even when the components concerned are generally not miscible or are very difficult to mix. The device has a body ( 8 ) which is located in a throughflow chamber ( 4 ) and is difficult to flow around. This body is situated at least partially in a part of the throughflow chamber ( 4 ) that expands in the direction of the flow, so that the cavitation effect and the mixing effect of the supercavitation field produced by the body ( 8 ) that is hard to flow around are considerably amplified.

Abstract: The individual cylinders of the internal combustion engine are divided into at least two cylinder banks wherein each is assigned a separate exhaust-gas channel. Secondary air is conveyed by a compressor. The flow of the secondary-air mass flow is set independently by an electrically controllable throughflow control. A value for the entire secondary-air mass flow is determined from the signal of a secondary-air mass sensor. The throughflow control is controlled into an open position, the value for the entire secondary-air mass flow is detected and subsequently the throughflow control is controlled into a closed position, the values for the secondary-air mass flows are detected before and after closure, and these values are compared with a plurality of different threshold values and, as a function of the result of the comparisons, a determination is made of the fault location with regard to the respective cylinder bank.

Abstract: The invention relates to a touchless control sanitary installation comprising a water collection container (1), water outlet fittings, throughflow adjusting means, actuating means (3, 4) for touchless control and an electronic control device. Upstream of the water outlet (2), on the mains supply side, a cold water conduit and a hot water conduit are combined, one throughflow adjusting means each being disposed therein. The actuating means (3, 4) are two proximity sensors the signals of which are evaluated by the control electronics. The aim of the invention is to provide a sanitary installation that is characterized by its ease of use, a compact design and low susceptibility to failure, an unintentional opening of the water conduits being avoided. For this purpose, the sensor fields (5, 6) are configured in such a manner that an individual coming closer to the installation or an object present in the area of the outlet of the water outlet does not trigger actuation of the throughflow adjusting means. If the water outlets are deliberately opened, the control electronics control the throughflow means disposed in the two water conduits in opposite directions in such a manner that the rate of flow of the water dispensed via the water outlet (2) remains substantially constant.

Abstract: Electric resistance water heaters are relatively simple and are therefore one of the most common water heating configurations. Due to constraints on the allowable instantaneous electrical power draw, most electric water heating systems incorporate a sizable thermal storage component. The inherently unsteady storage component therefore has an overwhelming impact on the system behavior. In this investigation, a residential-scale electric storage water heater was tested across a range of flow rates for both powered and nonpowered discharge processes as well as for charge processes with no throughflow. The flow dynamics internal to the storage volume is shown to be strongly multidimensional and transient, especially when the internal heating elements are energized. Comparison of the measured data to the performance limits of a system with a fully mixed or a perfectly stratified storage element reveals that the conventional system operates relatively near to the fully mixed limit. As a result, there appears to be significant potential for improvements in system performance through reductions in the level of thermal mixing internal to the storage volume.

Abstract: The description is given of a sanitary water-outflow fitting, in particular a tub-filling mixer unit, having a water-outflow housing ( 1 ) and a jet former for a wide-surface-area water-outlet jet ( 19 ), the jet former being arranged in the housing. The water-outflow housing ( 1 ) comprises an elongate supply channel ( 21 ) which runs essentially perpendicularly to the water-outlet jet ( 19 ), tapers in a funnel like manner in the throughflow direction and is bounded by an intermediate wall ( 37 ). The intermediate wall ( 37 ) has a multiplicity of throughflow holes ( 51 ), via which the supply channel ( 21 ) is connected to an elongate distributor chamber ( 11 ) essentially parallel to it. The distributor chamber ( 11 ) has at least one water-outlet channel ( 9 ) leading to the water outflow.

Abstract: This study describes the development of a computer program for analyzing the off-design performance of axial flow helium compressors, which is one of the major concerns for the power conversion system of a high temperature gas-cooled reactor (HTGR). The compressor performance has been predicted by the aerodynamic analysis of meridional flow with allowances for losses. The governing equations have been derived from Euler turbomachine equation and the streamline curvature method, and then they have been merged into linearized equations based on the Newton-Raphson numerical method. The effect of viscosity is considered by empirical correlations to introduce entropy rises caused by primary loss sources. Use of the method has been illustrated by applying it to a 20-stage helium compressor of the GTHTR300 plant. As a result, the flow throughout the stages of the compressor has been predicted and the compressor characteristics have been also investigated according to the design specification. The program results show much better stability and good convergence with respect to other through-flow methods, and good agreement with the compressor performance map provided by JAEA. (authors)

Abstract: The invention relates to an apparatus for metering all kinds of liquids, preferably water, for example for installation on water taps for domestic or commercial use, with the throughflow of water being interrupted after the desired amount is metered.

Abstract: Darcy's law is a mathematical relationship originally determined by Henry Darcy in 1856 that permits quantification of fluid flow through porous media. Many sophisticated theoretical and practical derivations have been based on Darcy's law, and it has become the foundation for quantitative groundwater flow science and soil physics. In its most useful form, the formula can be used to calculate the amount of water (or other fluid) flowing through a given cross-sectional area of a porous substance and equates volumetric discharge per unit time (q) to the product of area (A), hydraulic gradient (I = change in head per unit length) and a coefficient (K = saturated hydraulic conductivity). In its simplest terms, the relationship may be expressed as q = KIA. Keywords: groundwater flow; soil water; hydraulic conductivity; laminar flow; hydraulic gradient; throughflow

Abstract: There is a long history of drainage of blanket peat but few studies of the long-term hydrological impact of drainage. This paper aims to test differences in runoff production processes between intact and drained blanket peat catchments and determine whether there have been any long-term changes in stream flow since drainage occurred. Hillslope runoff processes and stream discharge were measured in four blanket peat catchments. Two catchments were drained with open-cut ditches in the 1950s. Ditching originally resulted in shorter lag times and flashier storm hydrographs but no change in the annual catchment runoff efficiency. In the period between 2002 and 2004, the hydrographs in the drained catchments, while still flashy, were less sensitive to rainfall than in the 1950s and the runoff efficiency had significantly increased. Drains resulted in a distinctive spatial pattern of runoff production across the slopes. Overland flow was significantly lower in the drained catchments where throughflow was more dominant. In the intact peatlands, matrix throughflow produced by peat layers below 10 cm was rare and produced <1% of the runoff. However, in drained peatlands, matrix throughflow in deeper peat layers was common and provided around 23% of the runoff from gauged plots. Macropore flow, the density of soil piping, and pipeflow were significantly greater in drained peatlands than in intact basins. Gradual changes to peat structure could explain the long-term changes in river flow, which are in addition to those occurring in the immediate aftermath of peatland drainage.

Abstract: Waters moving east through the Arctic Ocean significantly contribute to nitrogen fixation in the Atlantic.

Abstract: Analysis both based on the wind stress and ocean assimilation dataset shows that the interannual variability of the Indonesian Throughflow and the South China Sea (Luzon Strait) Throughflow is out of phase. Wind anomaly forcing in the equatorial Pacific plays an important role in setting up this phase relation. During El Nino events, the westerly wind bursts intensify the Northern Equator Current and induce a northward shift of its bifurcation point. As a result, the partition of volume transport between the Kuroshio and the Mindanao Current is changed, with the Kuroshio transport decreased and the Mindanao Current increased. The undershooting/overshooting phenomena occur at the Luzon Strait and the Sulawesi-Mindanao passage, caused by variability of these two currents. Water transport from the Pacific to the South China Sea increases with the Kuroshio transport decreased, and transport from the Pacific to the Indian Ocean decreases with the Mindanao Current transport increased. The situation is reversed during La Nina. Therefore, the ocean dynamic meaning is profound to study the interannual variability relationship between the Indonesian Throughflow and the Luzon Strait Throughflow.