Abstract: [1] A nested numerical model system has been set up to realistically simulate almost 40 years of the Indonesian throughflow (ITF). A global circulation model delivered the boundary values for sea surface height, temperature and salinity distribution to a fine resolution regional model of the ITF. The results of the regional model are in good agreement with measured data regarding velocity distribution, stratification as well as transported water masses, even though the division of the ITF volume transport into its western and eastern branches differs slightly from estimates from other model results or measurements. The results show a current system highly variable in space and time. Here, the analysis of model results focuses on the western branch of the ITF, the Makassar Strait throughflow, which is estimated to account for up to 50 to 80% of the entire ITF. The climatology and the mean vertical structure are presented. The model results show that the Makassar Strait throughflow occurs as a distinct current, which we termed Makassar Current. It is regionally developed as a subsurface jet, and it behaves like a western boundary current as it is attached to the western boundary (Sunda Shelf edge) along its entire path from the Sulawesi Sea through the Makassar Strait to its direct exit through the Lombok Strait. It appears from model experiments that the local wind stress counteracts the Makassar Strait throughflow.

Abstract: This work proposes an optimization strategy for the preliminary stage of turbomachinery design, based on the application of a throughflow code in the context of a fully automated optimization strategy. The code solves for the circumferentially-averaged flow equations, including the effects of aerodynamic and friction forces and of blade thickness; the outcome of the code is the flow distribution on the meridional surface. In this research the definition of an ‘optimal’ mean flow surface is the final aim of a multi-objective optimization procedure, in which non-concurrent goals are simultaneously considered. Evolutionary algorithms are used in the global optimization process, based on the coupling of a Genetic Algorithm with a metamodel.The optimization method is applied to a low speed axial compressor, for which the optimization goals are the minimization of aerodynamic loss and discharge kinetic energy at the exit of the stage, as well as the uniformity of work exchange along the blade span. The method proves to match all the objectives, providing a clear improvement with respect to classical and well-established design methods.Copyright © 2012 by ASME

Abstract: This paper investigates the onset of convection in a vertical cylinder occupied by a saturated porous medium of vertically heterogeneous permeability. The flow is induced by an applied vertical temperature gradient and an imposed solute concentration gradient. The main interest of this paper is studying the effect of vertical throughflow on the onset of instability in this system. The study is performed using linear stability theory. The problem is of considerable interest for hydrological and geophysical situations.

Abstract: The effect of vertical throughflow on the onset of penetrative convection simulated via internal heating in a two-layer system in which a layer of fluid overlies and saturates a layer of porous medium is studied. Flow in the porous medium is governed by Forchheimer-extended Darcy equation, and Beavers–Joseph slip condition is applied at the interface between the fluid and the porous layers. The boundaries are considered to be rigid, however permeable, and insulated to temperature perturbations. The eigenvalue problem is solved using a regular perturbation technique with wave number as a perturbation parameter. The ratio of fluid layer thickness to porous layer thickness, ζ, the direction of throughflow, and the presence of volumetric internal heat source in fluid and/or porous layer play a decisive role on the stability characteristics of the system. In addition, the influence of Prandtl number arising due to throughflow is also emphasized on the stability of the system. It is observed that both stabilizing and destabilizing factors can be enhanced because of the simultaneous presence of a volumetric heat source and vertical throughflow so that a more precise control (suppress or augment) of thermal convective instability in a layer of fluid or porous medium is possible.

Abstract: An analysis is made of the effect of vertical throughflow on the onset of thermal convection in a horizontal layer of an electrically conducting fluid contained between two rigid permeable plates and heated from below in the presence of a uniform vertical magnetic field. The constant throughflow is measured by Peclet number Q and at both boundaries heat flux is held constant. It is found that when both boundaries are perfectly electrically conducting, the critical value of Rayleigh number R c t at the onset of steady convection increases with increase in Q for given values of the magnetic parameter R h , the Prandtl number p 1 and the magnetic Prandtl number p 2 with p 1 > p 2 . It is observed that the magnetic field inhibits the onset of steady convection. The analysis further reveals that R c t is independent of the sign of Q . When the lower plate is electrically non-conducting and the upper plate is perfectly electrically conducting, R c t is greater than the corresponding value of R c t for perfectly conducting plates for given values of Q , R h , p 1 and p 2 . It is also found that the positive throughflow ( Q > 0 ) is more stabilizing than the negative one ( Q 0 ) . The results are exemplified by considering some realistic cases e.g., liquid sodium and gallium.

Abstract: The effect of strong throughflow and strong heterogeneity on the onset of convection induced by a vertical density gradient in a saturated porous medium governed by Darcy’s law is investigated with the aid of a computer package. The general case, where there is heterogeneity in both the vertical and horizontal directions, and where there is heterogeneity in permeability, thermal conductivity, and applied temperature gradient, is considered. Previous work on the case of non-periodic global variation is now extended to the case of either periodic variation or localized variation.

Abstract: : As the only low-latitude connection between ocean basins, the Indonesian Throughflow allows the direct transmission of heat and salinity between the Pacific and Indian Oceans. The Mg/Ca and differential 18O of calcite of Globigerinoides ruber (G. ruber) were used to estimate the sea surface temperature (SST) and differential 18O of water, an indicator of hydrologic conditions, over the past 20,000 years. I also attempted to estimate thermocline structure using Pulleniatina obliquiloculata, but the Mg/Ca and differential 18O of calcite data yield conflicting interpretations, indicating further work on this proxy is required. The G. ruber Mg/Ca results suggest that the SST of the outflow passages were influenced by high latitude Southern Hemisphere temperature. At approximately 10,000 years before present, there was a warming in the Makassar Strait. This local warming was coincident with the flooding of the Sunda Shelf, which opened a connection between the South China Sea and the Indonesian Throughflow. Regional differential 18O of seawater reconstructions suggest that the mean position of the Intertropical Convergence Zone (ITCZ) was approximately the same as modern at the last glacial maximum and was displaced to the south during the Younger Dryas and Heinrich Stadial 1, suggesting the ITCZ responds to changes in the interhemispheric temperature gradient.

Abstract: Device for damping of sounds which comprises a casing (11 ) intended to be placed round one or more sou nd-generating equipment items, and a sound-damping panel (20) via which air is allowed to flow out from the casing. The sound-damping panel comprises a throughflow space (23) situated between a first wall (21 ) which faces towards the inside of the casing and a second wall (22) which extends along and at a distance from the first wall. The first wall is provided with a plurality of apertures (24) via which air is allowed to flow into the throughflow space. A diffuser means (25) is situated on the second wall directly opposite each aperture to deflect the air which via this aperture flows towards the second wall so that this air flow then proceeds in various different directions in the throughflow space. At least some of the internal surfaces of the throughflow space are covered with sound-absorbing material (29). Air is allowed to flow from the throughflow space and proceed to the surroundings via outlet apertures (31 ) of the sou nd-damping panel.

Abstract: Variation of Indonesian Throughflow transport, salinity, and temperature at surface level of Timor Seas monthly, seasonal, and annual mean scale was studied using the datasets provided by IRI/LDEO Climate Data Library i.e Simple Ocean Data Assimilation (SODA) for the salinity. The period data used in this study was 1995-2004, ERSST for the temperature. The Indonesian Thourghflow transport was obtained from Hautala et al. (2001). Result of this study showed there was influence of monsoon and ENSO on oceanographic parameters. During the South East (SE) monsoon, an emptiness on the surface water occurred in Timor Seas due to the easterly wind, which causes the upwelling. The results was also shown that during the SE monsoon the average temperature was 26.84oC, salinity was 34.35, and Indonesian Throughflow transpor was -0.34 Sv. While during the North Western (NW) monsoon the average temperature was 29.6 oC, salinity was 34.22, and the Indonesian Throughflow transport was -0.27 Sv. The negative value (-) means that the flow toward the Indian Ocean. In addition, based on temporal correlation between Indonesian Throughflow transport and NINO 3.4 index was found that the annual mean variability increases (-0.18 Sv) during La Nina period and decreased (-0.13 Sv) during period El Nino. These indicated that ENSO phenomena influenced the transport across the Equatorial Pacific east-west. Keywords: Indonesian throughflow, salinity, temperature, SODA, Monsoon, ENSO, Timor Seas.

Abstract: Variation of Indonesian Throughflow transport, salinity, and temperature at surface level of Timor Seas monthly, seasonal, and annual mean scale was studied using the datasets provided by IRI/LDEO Climate Data Library i.e Simple Ocean Data Assimilation (SODA) for the salinity. The period data used in this study was 1995-2004, ERSST for the temperature. The Indonesian Thourghflow transport was obtained from Hautala et al. (2001). Result of this study showed there was influence of monsoon and ENSO on oceanographic parameters. During the South East (SE) monsoon, an emptiness on the surface water occurred in Timor Seas due to the easterly wind, which causes the upwelling. The results was also shown that during the SE monsoon the average temperature was 26.84 o C, salinity was 34.35, and Indonesian Throughflow transpor was -0.34 Sv. While during the North Western (NW) monsoon the average temperature was 29.6 o C, salinity was 34.22, and the Indonesian Throughflow transport was -0.27 Sv. The negative value (-) means that the flow toward the Indian Ocean. In addition, based on temporal correlation between Indonesian Throughflow transport and NINO 3.4 index was found that the annual mean variability increases (-0.18 Sv) during La Nina period and decreased (-0.13 Sv) during period El Nino. These indicated that ENSO phenomena influenced the transport across the Equatorial Pacific east-west.

Abstract: Currents and throughflow transport in the Taiwan Strait (TS) are systematically analyzed using a new regional ocean reanalysis dataset (China Ocean ReAnalysis, CORA in brief), recently released by National Marine Data and Information Service (NMDIS) in 2009, covering China's coastal waters and adjacent seas. The total throughflow volume transport through TS presents a seasonal variability with the annual-mean of 1.49Sv. It reaches maximum in summer with mean value of 2.33Sv, while in winter the mean transport falls to 0.78Sv on average. The estimated throughflow transport is in good agreement with the observational results. The comparisons of the results with historical observations and numerical simulations also show that CORA performs well on reproducing the currents and temperature field in TS region. In addition, CORA not only successfully reproduced the known oceanic phenomena in TS such as temperature front, up-wind flow in fall, winter northward flow blocking in Penghu Channel, and the winter antic...

Abstract: The present work concerns the turbulent flow inside a rotor-stator cavity with superimposed throughflow. The authors focused their analysis on a simple two-faced disk cavity, without shrouds, with interdisk-spacing sufficiently large so that the boundary layers developed on each disk are separated and the flow is turbulent. In such a system, the solid body rotation of the core predicted by Batchelor can develop. The evolution of the core-swirl ratio of the rotating fluid with an outward throughflow is studied by applying a classical experimental correlation, inserted in a one-dimensional (1D) in-house developed code. Results are compared to those predicted by CFD computations. Due to the discrepancies revealed, the authors provided a correction of the experimental correlation, based on CFD computation. Results thus obtained are finally in good agreement with CFD predictions.

Abstract: Modeling wetness phenomena in steam turbines can help to assess the weight of the different losses due to the liquid phase, and so provide a tool to evaluate possible design features and optimal operating conditions Since this analysis involves a whole section flow path, throughflow approach is more suitable than 3D CFD The paper presents a way to model deposition of fog droplets and motion of liquid film on blades in a wet steam turbine in a throughflow code For deposition, the contribution of turbophoresis is taken into account by using the deposition rate model established by Zaichik et al and the contribution of inertia is considered for deposition on the leading edges of blades The liquid film model considers liquid film as a surface entity, the mass and momentum conservation equations being integrated on the film thickness to calculate the averaged film thickness and velocity The liquid film is submitted to aerodynamic drag, blade friction and inertial effects This model is validated with an experiment conducted at the University of Michigan A parametric study on droplet size, thermodynamic conditions, friction velocity and on correction for rarefied gas effect has been performed on a single stage transonic turbineCopyright © 2012 by ASME

Abstract: A throughflow rate limiting device with a spring-loaded valve body which is disposed upstream of a cross-sectional constriction in a flow duct so as to be axially slideable between a first and a second position. The valve body is loaded by a spring in the direction of the first position, and for a given pressure gradient throughflow in the first position is greater than in the second position. The cross-sectional constriction may be bypassed by at least one bypass line which branches off from the flow duct upstream of the cross-sectional constriction and rejoins the flow duct downstream of the cross-sectional constriction. In order to achieve small flow resistance in the open state and abrupt switching, the valve body has the shape of a double cone.

Abstract: The invention relates to a throughflow rate regulator unit (2) having a carrier element (3) which extends over the clear cross section of a fluid line portion and which has spaced-apart insert openings (4), of which a throughflow rate regulator (6) is arranged in each case in at least two insert openings (4), wherein each throughflow rate regulator (6) comprises an annular throttle body (7) of elastic material which encloses a regulating core (8) and, between it and an inner and/or outer profiled circumferential wall (9), delimits a control gap (10) which changes under the pressure of the fluid flowing through.

Abstract: The present invention relates to a method for the automated management of a plurality of throughflow apparatuses (10) for producing a total throughflow of a fluid into and/or out of a storage apparatus (200), in particular a natural gas store, having the steps of: - inputting predefined values for the throughflow apparatuses (10) into an input unit (20), - transferring the input predefined values to a management unit (30), and - using the transferred predefined values of the management unit (30) for managing the throughflow apparatuses (10) in the control and/or regulation thereof.

Abstract: [1] A numerical model is used to investigate how the Indonesian Throughflow and tidal mixing are affecting the seasonal cycle of the sea surface temperature (SST) in the Indonesian Seas. The SST in these seas is considered to play a major role on the development of the Australian Summer Monsoon. Based on a quantitative assessment of the heat budget, the Indonesian Throughflow is found to affect the SST in the western Indonesian Seas primarily during Austral summer. The Throughflow advects the warm water from the Pacific and maintains the warm SST when the Northwestern Monsoonal wind induces coastal upwelling along the northern side of the Nusa Tenggara and cools the SST. Such balance is supported by observations. The hydrographic sections show the isotherms tilting upward toward the northern coast of the Nusa Tenggara when satellite observations show slight decrease of the SST in the region. Tidal mixing is found to cool the SST during summer the most. This is because the Northwest Monsoonal wind induces coastal upwelling near where strong tidal mixing above seamount occurs and brings the tidally well-mixed upper thermocline water to the surface. The surface Ekman flow also spreads this cool water around the Banda Sea where tidal mixing does not occur. The impact of tidal mixing on the SST is also found to come largely from that occurring above seamounts. The impact of tidal mixing on the continental shelves is limited to shelf-breaks because cold subsurface water is necessary for enhanced vertical mixing to cool the SST.

Abstract: The role of viscous heating in the onset of the instability in a liquid-saturated porous medium is studied. The change of the liquid viscosity with the temperature is taken into account by using a linear fluidity model. The system examined is a horizontal porous layer with an adiabatic lower boundary and an isothermal upper boundary. The combined effects of the viscous heating and of the variable viscosity yield a basic stationary and parallel throughflow in a horizontal direction. This basic solution may display singularities when the product between the Peclet number and the viscosity-temperature slope parameter exceeds the threshold value π/2. The linear stability of the basic solution is studied with respect to normal modes disturbances arbitrarily oriented to the basic flow direction. In all the physically realistic cases, the most unstable disturbances are proved to be the longitudinal rolls (the wave vector is perpendicular to the basic velocity). The instability to the longitudinal rolls occurs when the product between the Peclet number and the viscosity-temperature slope parameter exceeds its critical value. This critical value is smaller than π/2, for every nonzero value of the buoyancy parameter, viz., the Gebhart number. As a consequence, the parametric domain where the singularities of the basic solution arise is in fact included in the instability domain.

Abstract: Three-dimensional Rayleigh–Benard instabilities in binary fluids with Soret effect are studied by linear biglobal stability analysis. The fluid is confined transversally in a duct and a longitudinal throughflow may exist or not. A negative separation factor , giving rise to oscillatory transitions, has been considered. The numerical dispersion relation associated with this stability problem is obtained with a two-dimensional Chebyshev collocation method. Symmetry considerations are used in the analysis of the results, which allow the classification of the perturbation modes as modes (those which keep the left–right symmetry) or modes (those which keep the symmetry of rotation of about the longitudinal mid-axis). Without throughflow, four dominant pairs of travelling transverse modes with finite wavenumbers have been found. Each pair corresponds to two symmetry degenerate left and right travelling modes which have the same critical Rayleigh number . With the increase of the duct aspect ratio , the critical Rayleigh numbers for these four pairs of modes decrease and closely approach the critical value obtained in a two-dimensional situation, one of the mode (a mode called mode A) always remaining the dominant mode. Oscillatory longitudinal instabilities ( ) corresponding to either or modes have also been found. Their critical curves, globally decreasing, present oscillatory variations when the duct aspect ratio is increased, associated with an increasing number of longitudinal rolls. When a throughflow is applied, the symmetry degeneracy of the pairs of travelling transverse modes is broken, giving distinct upstream and downstream modes. For small and moderate aspect ratios , the overall critical Rayleigh number in the small Reynolds number range studied is only determined by the upstream transverse mode A. In contrast, for larger aspect ratios as , different modes are successively dominant as the Reynolds number is increased, involving both upstream and downstream transverse modes A and even the longitudinal mode.

Abstract: In this study the interannual variability of the upper-ocean heat content in the South China Sea (SCS) was revisited using simple ocean data assimilation (SODA) combined with objective analyzed data sets that included the horizontal and vertical structures. The results confirmed that the upper-ocean heat content in the SCS is lower than normal during the mature phase of El Nino events, and two super El Nino events, 1982/1983 and 1997/1998 were also included. The variability of the heat content was consistent with the variability of the dynamic height anomalies. The SCS throughflow (SCSTF) plays an important role in regulating the interannual variability of the heat content, especially during the mature phase of El Nino events.