Abstract: Satellite altimeter data reveal that the strongest intraseasonal variability in the southeast Indian Ocean occurs in the South Equatorial Current (SEC) during the second half of the year The length scale of the variability is 100–150 km, with a westward phase speed of 15–19 cm s−1 and dominant periods between 40 and 80 days A continuously stratified quasigeostrophic model is solved to analyze the baroclinic stability of the climatological SEC Large growth rate of the instability waves (with e-folding timescale of less than 50 days) can be found east of the active region of intraseasonal variability during the July–September season, when the SEC and the Pacific to Indian Ocean throughflow are at their strongest Geostrophic current shear in the upper 200-m ocean is crucial for the growth of the instability The results suggest that the baroclinic instability draws most of its energy from the available potential energy associated with the throughflow, and, to a lesser degree, by local Ekman pump

Abstract: The influences of the large-scale interannual variations in the eastern Indian Ocean on the variability of the Indonesian throughflow are investigated by using an ocean general circulation model, driven by the ERS satellite winds from July 1992 to June 1997. The empirical orthogonal function (EOF) analysis of the simulated surface dynamic height variability captures two dominant modes on an interannual time scale, which are quite consistent with the available observations. The first mode indicates large amplitude in the western tropical Pacific and has a strong relation to the El Nino events, while the second EOF exhibits the large amplitude in the eastern Indian Ocean. The simulated net Indonesian throughflow shows an interannual variation of amplitude of about 15 Sv, with large transport from the Pacific to the Indian Ocean during 1994/95 and small transport during 1992 and 1997. It turns out that the net throughflow variation shows a high correlation with the second EOF mode (r = 0.51) for the whole five-year simulation. On the other hand, the correlation with the first mode is rather low (r = −0.07). However, the relative importance of the EOF modes to the throughflow variability changes with time. The upper-layer transport above a depth of 230 m in the Indonesian archipelago is also affected by the second mode. The difference in the upper-layer transport across 1°S and 110°E generates warm water convergence/divergence with a magnitude of 4 Sv within the Indonesian Seas on the interannual time scale, which shows good correspondence with sea surface temperature variation averaged over the Indonesian archipelago.

Abstract: We consider gravitational instability of a saline boundary layer formed by evaporation induced upward throughflow at a horizontal surface of a porous medium. Two paths are followed to analyse stability: the energy method and the method of linearised stability. The energy method requires constraints on saturation and velocity perturbations. The usual constraint is based on the integrated Darcy equation. We give a fairly complete analytical treatment of this case and show that the corresponding stability bound equals the square of the first root of the Bessel function J 0 . This explains previous numerical investigations by Homsy & Sherwood [1975, 1976]. We also present an alternative energy method using the pointwise Darcy equation as constraint, and we consider the time dependent case of a growing boundary layer. This alternative energy method yields a substantially higher stability bound which is in excellent agreement with the experimental work of Wooding et al. [1997a, b]. The method of linearised stability is discussed for completeness because it exhibits a different stability bound. The theoretical bounds are verified by two-dimensional numerical computations. We also discuss some cases of growing instabilities. The presented results have applications to the theory of stability of salt lakes and the salinization of groundwater.

Abstract: The outflow from the Indonesian seas empties approximately 5‐7 Sv of surface warm (and low salinity) Indonesian Throughflow water into the southern Indian Ocean (at roughly 12 8S). Using a nonlinear 1‰-layer model with a simple geometry consisting of a point source (of anomalous water) situated along a meridional wall on a b plane, the spreading of these waters is examined. An analytical solution is constructed with the aid of the ‘‘slowly varying’’ approach, and process-oriented numerical simulations are performed. It is found that, immediately after emptying into the ocean, the outflow splits into two branches. One branch carries approximately 13% of the source mass flux and forms a chain of high amplitude anticyclonic eddies (lenses) immediately to the west of the source. These eddies drift westward and penetrate into the interior of the Indian Ocean. The second branch carries the remaining 87% of the mass flux via a coastal southward flowing current. Ultimately, this second branch separates from the coast and turns westward. (A detailed examination of this second branch separation is, nevertheless, beyond the scope of this study.) It is suggested that the eddies recently observed to the west of the Island of Timor are a result of the above eddy generation process, which is not related to the classical eddy generation process associated with instabilities (i.e., the breakdown of a known steady solution). It is also suggested that this new nonlinear process explains why some of the Indonesian Throughflow water forms the source of the southward flowing coastal Leeuwin Current.

Abstract: The effects of the Indonesian throughflow on the upper thermocline circulation and surface heat flux over the Indian Ocean are presented for a 3-D ocean model forced by two different monthly wind–stress climatologies, as they show interesting differences, which could have implications for long-term variability in the Indian and Australasian monsoons. The effects are determined by contrasting a control run with a run in which the throughflow is blocked by an artificial land-bridge across the exit channels into the Indian Ocean. In the model forced by ECMWF wind stresses, there is little impact on the annual mean surface heat flux in the region surrounding the throughflow exit straits, whereas in the model forced by SSM/I-based wind stresses, a modest throughflow of less than 5 ×106 m3s–1 over the upper 300 m induces an extra 10–50 Wm–2 output. In the SSM/I-forced model, there is insignificant penetration of the throughflow into the northern Indian Ocean. However, in the ECMWF-forced model, the throughflow induces a 5–10 Wm–2 reduction in heat input into the ocean, i.e., an effective output, over the Somali Current in the annual mean. These differences are attributed to differences in the strength and direction of the Ekman transport of the ambient flow, and the vertical structure of the transport and temperature anomalies associated with the throughflow. In both models, the throughflow induces a 5–30 Wm–2 increase in net output over a broad swathe of the southern Indian Ocean, and a reduction in heat output of 10–60 Wm–2 in a large L-shaped band around Tasmania. Effective increases in throughflow-induced net output reach up to 40 (60) Wm–2 over the Agulhas Current retroflection in the ECMWF (SSM/I)-forced model. Seasonal variations in the throughflow's effect on the net surface heat flux are attributed to seasonal variations in the ambient circulation of the Indian Ocean, specifically in coastal upwelling along the south Javan, west Australian, and Somalian coasts, and in the depth of convective overturning between 40°S to 50°S, and its sensing of the mean throughflow's thermal anomaly. The seasonal anomalies plus annual mean yield maximum values for the throughflow-induced net surface heat output in boreal summer. Values may exceed 40 Wm–2 in the southern Indian Ocean interior in both models, exceed 60 Wm–2 over the Agulhas retroflection and immediate vicinity of the exit channels in the SSM/I-forced model, and reach 30 Wm–2 over the Somali jet in the ECMWF-forced model.

Abstract: Ameliorative strategies are urgently required in some agricultural catchments in southern Australia to reduce the loss of potential contaminants to streams. However, a better understanding of where the contaminants are generated on hillslopes, their forms, and the pathways through which they are transported were required. Thus, seasonal changes in the quantities and forms of several chemical species were measured in both vertical and lateral flow pathways at 4 sites along a toposequence in the Mt Lofty Ranges, South Australia. Instrumentation was installed to measure and quantify overland flow and throughflow, and porous-wick samplers were installed at 2 depths to study the chemistry of leachate. Neutron moisture meter access tubes were installed to measure seasonal changes in soil water content with depth as this influences chemical concentrations and mobility. In years of average to below average annual rainfall, throughflow was the most important transport pathway for contaminants. However, it was expected that overland flow will be the dominant transport pathway when annual rainfall is above about 550 mm. Changes in water content of the texture-contrast soils was caused by seasonal rainfall causing periodic saturation, by waterlogging, groundwater, or both. This affected the type and form of contaminant. For example, Na and Cl concentrations were generally only large (800 and 1500 mg/L, respectively) on the lower slopes but in the wettest seasons their concentrations increased at depth on mid-slopes due to the influence of shallow saline groundwater. These chemicals then leached when groundwater levels subsided. The results suggest that ameliorative strategies to reduce agricultural contaminants should target the transport pathways specific to each chemical species, at the point (or points) in the landscape where they are generated.

Abstract: CConvective instabilities caused by a nonuniform temperature gradient due to vertical throughflow and internal heat generation were investigated in an anisotropic porous layer. The boundaries are taken to be either impermeable or porous and are perfect conductors of heat. The Forchheimer-extended Darcy model is used to describe the flow in the porous medium. The resulting eigenvalue problem is solved numerically by the Galerkin method with a modified external Rayleigh number as the eigenvalue. Both anisotropic parameters (i.e., effective thermal diffusivity, η, and permeability, ξ) appear through their ratio η/ξ only. We found that an increase in η/ξ increases the stability of the system. Furthermore, we observed that in the absence of internal heat generation, throughflow stabilizes when the boundaries are symmetric and destabilizes when they are asymmetric. However, if an internal heat source exists, throughflow destabilizes the system irrespective of the boundary types considered. A more precise control of the buoyancy-driven instability may be achieved by tuning the anisotropy parameters and internal heat source strength. Copyright © 2002 by Begell House, Inc.

Abstract: The lateral down-slope movement of water, NO3 -, NH4 +, SO4 2-, H+ and DOC through an ablation till was examined from 1987 to 1990 for a one hectaresoil catena on a steep hillslope with uniform forest cover at the Turkey Lakes Watershed (TLW), Ontario, Canada. Natural variation in the export of nutrients from the soil profile via soil water to Little Turkey Lake was assessed in relation to nutrient distribution in soil at different topographic positions.Subsurface throughflow exhibited dramatic differences in nutrientconcentrations and fluxes with slope position, largely reflectingthat of the soil horizons through which the water passed. GreaterNO3 -, SO4 2-, and DOC concentrations in subsurface water in the upper, well-drained hillslope were a reflection of enrichment by contact with more acidic, more developed podzols, and more favorable soil physical and biological conditions for NO3 - retention in solution.Nutrient inputs to the lake were strongly influenced by increaseddown-slope transport of water, and increased SO4 2-, N, and C retention in wetter, less-developed podzolic soils that characterize lower slope positions. An understanding of water movement and soil development variation withtopographic position was required to accurately estimate nutrient budgets for steep slopes at TLW.

Abstract: We conduct a theoretical analysis of steady-state heat transfer problems through mid-crustal vertical cracks with upward throughflow in hydrothermal systems. In particular, we derive analytical solutions for both the far field and near field of the system. In order to investigate the contribution of the forced advection to the total temperature of the system, two concepts, namely the critical Peclet number and the critical permeability of the system, have been presented and discussed in this paper. The analytical solution for the far field of the system indicates that if the pore-fluid pressure gradient in the crust is lithostatic, the critical permeability of the system can be used to determine whether or not the contribution of the forced advection to the total temperature of the system is negligible. Otherwise, the critical Peclet number should be used. For a crust of moderate thickness, the critical permeability is of the order of magnitude of 10(-20) m(2), under which heat conduction is the overwhelming mechanism to transfer heat energy, even though the pore-fluid pressure gradient in the crust is lithostatic. Furthermore, the lower bound analytical solution for the near field of the system demonstrates that the permeable vertical cracks in the middle crust can efficiently transfer heat energy from the lower crust to the upper crust of the Earth. Copyright (C) 2002 John Wiley Sons, Ltd.

Abstract: Temporal flow behaviors in a heated rotating cavity with an axial throughflow and sealed annulus are explored. Generally, for both systems, the ratio of the flow angular velocities to the system boundaries are found, even close to boundaries, not equal to unity. Both systems exhibit similar temporal velocity gradient component distributions. Most unsteadiness corresponds to regions of high tangential velocity gradients. As a result of the flow drift, these spatial gradients are converted to temporal gradients. For the present flows, computations suggest judicious coordinate system angular velocity choices may reduce demands on both convective term treatments and computer resources.

Abstract: The main significance of this paper is that a realistic, three-dimensional, high-resolution primitive equation model has been developed to study the effects of dense water formation in Arctic coastal polynyas. The model includes realistic ambient stratification, realistic bottom topography, and is forced by time-variant surface heat flux, surface salt flux, and time-dependent coastal flow. The salt and heat fluxes, and the surface ice drift, are derived from satellite observations (SSM/I and NSCAT sensors). The model is used to study the stratification, salt transport, and circulation in the vicinity of Barrow Canyon during the 1996/97 winter season. The coastal flow (Alaska coastal current), which is an extension of the Bering Sea throughflow, is formulated in the model using the wind-transport regression. The results show that for the 1996/97 winter the northeastward coastal current exports 13% to 26% of the salt produced by coastal polynyas upstream of Barrow Canyon in 20 to 30 days. The salt export occurs more rapidly during less persistent polynyas. The inclusion of ice-water stress in the model makes the coastal current slightly weaker and much wider due to the combined effects of surface drag and offshore Ekman transport.

Abstract: A throughflow collection system is established to investigate the process of runoff generation both for surface flow and subsurface flow.The results show that:1.under the condition of flurry,surface runoff will be generated and the lag phenomenon may happen to the flow peak if the soil is dry before the rain; 2.both surface runoff and throughflow commence under the condition of rainstorm and downpour; 3. under the condition of flurry and rainstorm,surface runoff is controlled primarily by infiltrationexcess runoff mechanism.The numerical simulation can be used to explore the general tendency of the surface runoff.

Abstract: A system has been developed for measuring non-shunt cardiac output by the throughflow technique, using nitrous oxide in patients undergoing general anaesthesia The throughflow measurement technique is a non-invasive method based on inert gas throughflow theory In vitro validation of the measurement system was performed using a lung gas exchange simulator The accuracy and precision of the throughflow measurement system was assessed by comparing measured and target values for five simulated values of non-shunt cardiac output, from 288 to 986 l min−1 This showed an overall mean bias of −003l min−1 (range −000 to −010 l min−1), with a mean coefficient of variation of the difference of 139% (120–193%) These results indicate that the measurement system is suitable for monitoring the non-shunt cardiac output in patients undergoing general anaesthesia using nitrous oxide throughflow

Abstract: An analytical study is made of the transient adjustment process of an initially stationary, stably stratified fluid in a square container. The boundary walls are highly conducting. The overall Rayleigh number Ra is large. Flow is initiated by the simultaneous switch-on of a temperature increase (δT) at the vertical wall and a forced vertical throughflow (Ra−1/4δw) at the horizontal walls. The principal characteristics are found by employing the matched asymptotic expansion method. The flow field is divided into the inviscid interior, vertical boundary layers and horizontal boundary layers and analyses are conducted for each region. The horizontal boundary layers are shown to be of double-layered structure, and explicit solutions are secured for these layers. Evolutionary patterns of velocity and temperature in the whole flow domain are illustrated. Both opposing (δw/δT > 0) and cooperating (δw/δT 1/ √2), (b) a buoyancy-convection-dominant mode (0 < δw/δT < 1/√2), and (c) a static mode (δw/δT ≈ 1/√2). Global evolutionary processes are depicted, and physical rationalizations are provided.

Abstract: Two flow instabilities involving a bifurcated flow pattern were discovered for the throughflow jet in a stepped labyrinth seal cavity. These instabilities, along with self-sustained flow oscillations, were experimentally explored to obtain a preliminary understanding of this phenomenon. Computer-captured visualization videos were used to measure the oscillation amplitudes and frequencies, as well as the mean value, of the throughflow jet trajectory angle. It was found that, depending on the seal cavity tooth clearance and radial height of the step, the flow pattern of the throughflow jet leaving the step corner was either 1) nonbifurcated, 2) always bifurcated, or 3) oscillatory bifurcated. A bifurcation stability map was developed showing which combinations of tooth clearance and step height lie in which of the three flow regimes. It was also found that the intermediate value of step height in the presence of the small tooth clearance exhibited the sharpest flow deflection and largest oscillation amplitude, as well as the highest mean-flow leakage resistance. Furthermore, for larger tooth clearances, the large step height cases, located farthest on the stability map into the oscillatory bifurcated regime, gave the highest leakage resistance.

Abstract: It is inter alia an apparatus for evaporating and superheating at least one medium described, comprising at least two reaction stages, wherein at least one first reaction stage is constructed as evaporator (20) for at least partial evaporation of at least one medium. The evaporator (20) has at least one throughflow device for passing the medium to be evaporated and a heating means for providing heat energy for at least partially evaporating the medium flowing through the throughflow device, the throughflow device with the heating means is thermally coupled. Furthermore, at least one is below the evaporator (20) second reaction stage as a superheater (50) formed for superheating the evaporated medium. The superheater (50) has a throughflow appliance for the passing of the evaporator (20) emerging medium and a superheating device for providing heating energy for superheating the the throughflow medium flowing through, wherein the throughflow device of the superheater is thermally coupled. In order to provide a powerful yet compact device, the invention provides that the at least one evaporator (20) and the at least one superheater (50) is formed as a layer composite of individual layers, that the Durchstromeinrichtungen of the evaporator (20) and of the superheater (50 ) have at least one layer with channel structure with at least one channel and at least one layer of the throughflow device of the evaporator (20) having at least one layered heating device and at least one layer of the throughflow device of the superheater with a layer-shaped overheating means is connected at least.

Abstract: The water outlet fitting for a washbasin has a housing with a cold water inlet, water outlet and an electronic control for an electro-magnetic water valve. The electronic control (10) and the electro-magnetic water valve (9) are arranged in the interior of the housing (4,5). An electric heating element (12) is fitted inside the housing, which heats the cold water. The electronic control is an approach sensor, which dependent upon the approach of body parts of a user opens the water valve and/or switches on the electrical heating element. The heating element is a throughflow heater with a heating spiral, around which cold water directly flows. A device is provided for temperature and/or quantity pre-selection (14).

Abstract: The method involves delivering the secondary air via a throughflow control valve whose opening is controlled in synchronism with the crankshaft angle. The throughflow control valve is controlled in synchronism with the crankshaft angle during the vacuum stage of a pressure pulse during the exhaust phase. The throughflow control valve can be controlled to open several times per crankshaft revolution.

Abstract: The invention relates to an apparatus and a process for the throughflow sterilization of biologically contaminated liquids.

Abstract: A dosing device for sanding devices, comprising a dosing piston (1) for sealing and releasing the throughflow opening for the grit. The dosing piston (1) and the opposite housing wall (4) of the throughflow opening have overlapping profile sections (56) enabling the grit to flow outward in a labyrinthine manner.

Abstract: The throughflow measurement arrangement has a measurement pipe (1) through which the medium flows, and a difference pressure sensor (12) associated with the measurement pipe. The wall (2) of the measurement pipe has an opening (3) in which a modular sensor housing that carries the difference pressure sensor can be sealed so as to be replaceable.

Abstract: The invention relates to a butterfly valve connection piece for an internal combustion engine, comprising a housing (1) and a throughflow opening (2) of said housing (1), in which a butterfly valve (7) is pivotably arranged around a pivotable axis extending in a perpendicular manner with respect to the longitudinal axis (9) of the throughflow opening (2), the butterfly valve is used to close the throughflow opening (2). When in a closed position, the butterfly valve (7) is inclined at a defined setting angle (10) in relation to the longitudinal axis (9) of the throughflow opening (2). The radial peripheral edge (8) thereof rests against the inner wall of the throughflow opening (2) and the throughflow opening (2) has a cylindrical shape at least in the region where the butterfly valve (7) comes to rest. The cylindrical region of rest in relation to the longitudinal axis (9) of the throughflow opening (2) forms a circular cylinder (17) which is cut on both sides at a certain angle, whereby the levels of the cut are inclined at a similar angle (10) in relation to the longitudinal axis (9) of the throughflow opening (2) and the butterfly valve (7) when arranged in a closed position.

Abstract: of EP0949446The fixture housing has a hood (1) and a connecting part (2) provided with throughflow channels (3,4) and end connecting flanges (5,6), all aligned with one another. The connecting part has a connection (7) inclined to the throughflow channels, the free end of which is closed by a plug (8). Inside the connection is a tubular dirt sieve (9), the interior of which is connected to the throughflow channel (3). The other throughflow channel (4) extends from the connecting flange (6) outwards into the connecting part. The connecting part has laterally and parallel to the throughflow channels a base (10). The hood has a round cross-section, which locates with its open end (12) tightly on the base and is provided with two laterally extending screw layers (13,14).

Abstract: The device has a control valve for load direction and speed with a seat valve blockage element in each load line with a control pressure surface acting towards a blocking position and subject to load pressure and a spring and a surface acting towards a throughflow position subject to pressure between the control valve and blockage element. The blockage element is actuated in the throughflow direction when the load line is connected to a container. The device has a control valve for controlling the direction and speed of motion of the load with a blockage element in each load line leading to the load for cut-off without leakage oil. The blockage element (15a, 15b) is a seat valve with a control pressure surface acting in the direction of a blocking position and subjected to load pressure and a spring and a control pressure surface acting in the direction of a throughflow position subjected to the pressure between the control valve and blockage element. The blockage element is actuated in the throughflow direction by an actuator when the load line (8a,8b) is connected to a container (11).

Abstract: The Indonesian Throughflow (ITF) is considered central to the heat budgets of the Pacific and Indian Oceans. Temperature and ocean current time series obtained within the Makassar Strait from December 1996 to early July 1998 are used to calculate heat transport of the ITF and assess its influence on Indian Ocean heat divergence. Velocity and temperature values for the surface layer that were not directly measured are extrapolated from the shallowest measurement to the sea surface using a variety of model profiles. While a single temperature profile is used based on a linear interpolation from NCEP OI sea-surface temperatures to the top-most mooring temperature recorder, four different velocity profiles are employed. Heat transport is calculated as volume transport multiplied by temperature, density and specific heat, using reference temperatures between 0°C and 4°C. The mean heat transport averages 0.55 PW relative to 0°C, and 0.41 PW relative to 4°C for the two most reasonable velocity profiles. In comparison, model heat transport values are larger, between 0.6 and 1.15 PW. Heat transport varies with ENSO phase, lower during El Nino, higher during La Nina. As 1997 was a strong El Nino year, our heat transport estimate may be less than the climatic mean. The ITF water is advected towards Africa within the Indian Ocean South Equatorial Current, to eventually exit the Indian Ocean across 30°S, most likely within the Agulhas Current. For realistic consideration of the ITF component within the Agulhas Current, the heat flux divergence of ITF waters within the Indian Ocean north of 30°S is found to be insignificant. Our results provide support for model studies and hydrographic geostrophic inverse calculations that indicate the ITF heat, derived from the Pacific Ocean, is ultimately lost to the atmosphere in the southwest Indian Ocean.

Abstract: Sensitivity of the global thermohaline circulation to interbasin freshwater transport by the atmosphere and the Bering Strait throughflow is investigated by using a free-surface, coarse-resolution ocean general circulation model. The model is run by prescribing freshwater flux at the sea surface without restoring the sea surface salinity to climatology in order that effects of salinity advection are properly represented. Comparison of experiments with the open and closed Bering Strait shows that the throughflow reduces the intensity of the Atlantic deep circulation by ∼17%, while minimally affecting the Pacific deep circulation. Increase in the atmospheric freshwater transport from the Atlantic to the Pacific intensifies both the Atlantic deep circulation and the Bering Strait throughflow. On the other hand, changes in the throughflow transport under a fixed amount of atmospheric interbasin freshwater transport are found to have a minor impact on the global thermohaline circulation. This insensit...