Abstract: A prediction model of shallow landsliding is proposed. It considers not only the deterministic aspects containing slope stability, saturated throughflow and a soil (regolith) depth development, but also the stochastic aspects of intensity and duration of rainfall. It turns out that the probability of saturated throughflow, which is the direct trigger mechanism to shallow landsliding, can be expressed by a log-normal distribution. The short term probability of landsliding is defined as the excess probability that the depth of saturated throughflow surpasses the critical value. The average recurrence interval T av of landsliding can be calculated as the expected value. This model was applied to a test field where a lot of shallow landsliding occurred at a heavy rainstorm in 1988. Then a DEM of 5-m grid interval was utilized to calculate T av at every grid point. Consequently, it was found that the percentage of the landslide grid number to the total grid number for every T av rank increases when T av decreases. Therefore, it is confirmed that T av is an index of the susceptibility to shallow landsliding and the distribution map of T av can be regarded as a kind of hazard map. The spatial distribution of T av reveals its significant dependence on the topography.

Abstract: Current variability at the Pacific entrance of the Indonesian Throughflow is investigated using direct current and hydrographic measurements. Two moorings with three current meters (depths of 350, 550, and 1050 m) and one conductivity-temperature-depth profiler (260 m) were deployed at 4°1′N, 127°31′E and 3°11′N, 128°27′E between Talaud Islands and Morotai Island (Indonesia) from February 1994 to June 1995. Data from four hydrographic surveys conducted mainly between Mindanao and New Guinea from 1994 to 1996 are also used. The onset of a strong northwestward flow was observed at the southern mooring during boreal winter. In contrast, a southwestward flow containing salty South Pacific water was observed there during boreal summer. This current pattern change matched monsoon change around the mooring sites, suggesting that this variability is a seasonal signal in this region. This current change may occur because of the meridional shift of the Halmahera Eddy associated with an enlargement/diminishment of the Mindanao Dome. Our observation result during summer (the southwestward flow with the South Pacific water at the southern mooring) suggests that the Maluku Sea is one of the eastern routes of the Indonesian Throughflow. The current data also revealed that intraseasonal variability occurs in 50-day oscillations. Because the coherence between wind variability in the tropics with a period of 40–50 days (Madden-Julian Oscillation) and current variability with this period are >0.4, it is possible that the 50-day oscillation in the ocean current is induced by wind variability associated with the Madden-Julian Oscillation. The ocean eddy activity with an intrinsic period in this region may also be related to this 50-day oscillation.

Abstract: The Indian Ocean general circulation is estimated by fitting the MIT Ocean General Circulation Model to the annual mean climatological hydrography and surface forcing, using the model and its computer-generated adjoint. Open boundary conditions are implemented to the west of the Indonesian Archipelago and near 30S. The approach simultaneously optimizes the initial conditions of the hydrographic fields, surface fluxes, and the open boundary conditions (temperature, salinity, and horizontal velocities). Compared to previous results obtained in a closed domain, the estimated velocity field shows a marked improvement near the southern boundary, with a reasonably strong Agulhas Current leaving the model domain. The Indonesian throughflow (ITF) is estimated as 2.7 Sv (1 Sv is 10^6 m^3/s) westward, which is on the low end of the range of previous estimates. The model is able to sharpen fronts in surface salinity, compared to climatology, and suggests that the low surface salinity values in the eastern equatorial region arise from advection out of the Bay of Bengal rather than from the ITF. Consistent with the closed-domain results, the meridional overturning is dominated by a shallow (above 500 m), wind-driven cell of 16 Sv maximum, which carries the bulk of the southward heat transport. We have defined generalizations of meridional heat and freshwater transports appropriate in the presence of a throughflow. The estimated meridional heat transport has a maximum of 0.8 PW at 12S, maximum freshwater transport is 0.29 Sv southward at 9S. The meridional transport divergences are well balanced by the surface heat and freshwater fluxes, indicating near-steady state and small influence of the ITF.

Abstract: Exact analytical solutions have been obtained for a hydrothermal system consisting of a horizontal porous layer with upward throughflow. The boundary conditions considered are constant temperature, constant pressure at the top, and constant vertical temperature gradient, constant Darcy velocity at the bottom of the layer. After deriving the exact analytical solutions, we examine the stability of the solutions using linear stability theory and the Galerkin method. It has been found that the exact solutions for such a hydrothermal system become unstable when the Rayleigh number of the system is equal to or greater than the corresponding critical Rayleigh number. For small and moderate Peclet numbers (Pe less than or equal to 6), an increase in upward throughflow destabilizes the convective flow in the horizontal layer. To confirm these findings, the finite element method with the progressive asymptotic approach procedure is used to compute the convective cells in such a hydrothermal system. Copyright (C) 1999 John Wiley & Sons, Ltd.

Abstract: Seasonal variations of upper-ocean mass transport between the Pacific and Indian Oceans via the Indonesian Throughflow (ITF) are examined using numerical experiments with a 1½-layer, reduced-gravity model forced with specific climatological winds. The model ITF transport, computed as a sum of through-strait transport, has an annual range of more than 8 Sv (an annual harmonic of amplitude 4.2 Sv and a smaller, semiannual harmonic amplitude of 0.5 Sv (Sv ≡ 106 m3 s−1), with peak transport from mid-April through July and minimum transport in November and December. Limited long-term observations make it difficult to validate these results, but they are consistent with current theory. Experiments with time-varying winds in specific regions show that most of the annual throughflow signal is due to equatorial winds (from 10°S to 10°N); ITF transport anomalies generated by off-equatorial winds account for less than 1 Sv and are mostly out of phase with the baseline throughflow signal. For the particular ...

Abstract: The role of the Indonesian Throughflow (ITF) in the thermocline circulation of the low-latitude Pacific Ocean is explored using a high-resolution primitive equation ocean circulation model. Seasonally forced runs for a domain with an open Indonesian passage are compared with seasonally forced runs for a closed Pacific domain. Three cases are considered: one with no throughflow, one with 10 Sv of imposed ITF transport, and one with 20 Sv of ITF transport. Two idealized tracers, one that tags northern component subtropical water and another that tags southern component subtropical water, are used to diagnose the mixing ratio of northern and southern component waters in the equatorial thermocline. It is found that the mixing ratio of north/south component waters in the equatorial thermocline is highly sensitive to whether the model accounts for an ITF. Without an ITF, the source of equatorial undercurrent water is primarily of North Pacific origin, with the ratio of northern to southern component water being approximately 2.75 to 1. The ratio of northern to southern component water in the Equatorial Undercurrent with 10 Sv of ITF is approximately 1.4 to 1, and the ratio with 20 Sv of imposed ITF is 1 to 1.25. Estimates from data suggest a mean mixing ratio of northern to southern component water of less than 1 to 1. Assuming that the mixing ratio changes approximately linearly as the ITF transport varies between 10 and 20 Sv, an approximate balance between northern and southern component water is reached when the ITF transport is approximately 16 Sv. It is also shown that for the isopycnal surfaces within the core of the equatorial undercurrent, a 2°C temperature front exists across the equator in the western equatorial Pacific, beneath the warm pool. The implications of the model results and the temperature data for the heat budget of the equatorial Pacific are considered.

Abstract: A multiblock multigrid Navier-Stokes solver has been extended to include a throughflow model for the design and analysis of turbomachines. The presence of the blades in the inviscid axisymmetric flow is modelled in the classical way through a distributed blade force to produce the desired turning, a blockage factor that accounts for the reduced area due to blade thickness, and a distributed frictional force representing the entropy increase due to viscous stresses and heat conduction. The exact blade geometry is not required. All features of the three-dimensional code concerning the physical fluid model, boundary conditions, spatial and time discretization, convergence acceleration techniques and data visualization are available to the throughflow module. This includes the capability to treat the entire range of relevant Mach numbers, from strictly incompressible (through a preconditioning technique) to supersonic, as well as any number of blade rows in any configuration, including, for example, bypass engines. Selected elements comprising the throughflow model are discussed, with special emphasis on the blade force and its discretization. The properties of analysis and design mode with respect to shocks and the associated losses are investigated. The methodology is demonstrated on a transonic compressor rotor and a four-stage low-speed turbine.

Abstract: The heater has a metal throughflow chamber with an inlet (2) and an outlet (3) and with at least one thick film heating element (10). The thick film heating element extends between the inlet and outlet on the outer surface. The thick film heating element has a tapering surface cross-section continuously reducing from the inlet to the outlet. Thick film temperature sensors can be mounted on the chamber near the inlet or outlet.

Abstract: The effects of a nonuniform temperature gradient and inertia arising due to throughflow on the onset of convection in a porous layer for different types of boundaries are investigated. Closed form solutions are obtained for the boundaries which are insulating to temperature perturbations, and for the conducting boundaries solutions are obtained using Galerkin technique. It is found that when the two boundaries are of the same type, the effect of throughflow is to stabilize the system irrespective of its direction. However, when the lower and upper boundaries are of different types, a small amount of throughflow in one particular direction destabilizes the system depending upon the values of the Prandtl number and the porous parameter. The standard results available are obtained as limiting cases.

Abstract: Laboratory experiments of runoff production in shallow soils were conducted on plots consisting of a bedrock layer, an intermediate soil layer, and a crushed stone cover layer. Artificial rainfall was supplied in varying amounts and time sequences; and surface runoff, soil layer interflow, and throughflow were measured. The purpose of the experiments was to investigate infiltration mechanisms in shallow soils and to characterize the effect of stone cover on the partitioning of rainfall at the soil surface. Two soil types were used: (1) A sandy loam; and (2) a silty clay loam. In the case of the sandy loam, the results showed that the majority of rainfall infiltrated readily into the soil, where it subsequently moved downward to the bedrock as throughflow. Strong throughflow response was attributed to preferential flow through large soil pores. Because these macropores formed naturally during the experiments, this work serves as a plot-scale demonstration of the role of rainfall as a factor of change of so...

Abstract: Trajectory experiments in a thermocline layer of an Indian Ocean model are used to investigate the role of different meridional transport mechanisms and quantify spreading pathways and rates under different forcing. Particles are introduced along two boundaries: the south Indian Ocean at 308S and the Indonesian Throughflow. Particles are advected horizontally within the layer by archived model velocity fields (˜ 83 ˜8 resolution) for a period of 50 years. The velocity fields are the result of forcing the model by monthly mean climatology (case A). The distribution of particles within the Tropics suggests efficient water mass blending; model results show a mixture of three parts South Indian Central Water to one part Indonesian Throughflow. In agreement with chlorofluorocarbon (CFC) observations, transport of thermocline waters along the western boundary into the northern Indian Ocean occurs on timescales of less than two decades. Additional Lagrangian experiments carried out with the seasonality removed from the velocity fields directly (taking the mean in case B) and from the forcing (case C) allow the role of horizontal eddy transport to be evaluated. Significant northward transport of southern subtropical gyre waters along the western boundary does not occur unless there is eddy transport, even though the mean flow appears to dominate the cross-equatorial transport in the immediate vicinity of the equator. Particles reach northward of 108N on shorter timescales (,20 yr) in case A compared with case C (.20 yr). Both the mean and seasonal forcing components are important for the meridional flux of particles. The results suggest that to adequately simulate meridional transport of mass and water mass properties in the Indian Ocean, models should include the full annual cycle. In a new methodology, CFC-11 concentrations along trajectories are calculated using observed CFC-11 concentrations for boundary conditions. Additional CFC observations allow model‐data comparisons to be made in the interior of the domain. The method may be useful in other studies of transport rates and processes where both computing power and good quality high-resolution observations are available.

Abstract: The onset of Marangoni convection with throughflow in a horizontal fluid layer with upper boundary free and insulating to temperature perturbations and the lower boundary rigid and either conducting or insulating to temperature perturbations is investigated. The resulting eigenvalue problem is solved exactly. The Prandtl number arising due to throughflow plays a crucial role in determining the stability of the system. It is found that a small amount of throughflow in one particular direction destabilizes the system depending on the Prandtl number and temperature boundary conditions.

Abstract: The effect of throughflow on the onset of Marangoni convection in a horizontal layer of micropolar fluid flow bounded below by a rigid isothermal surface and above by a nondeformable free adiabatic surface, for marginal state, is studied. The determination of the critical Marangoni number entails solving the eigenvalue problem numerically for which the Single-term Galerkin method is employed.

Abstract: We have tested a rigorous version of the Island Rule for the long-term mean magnitude of the Indonesian Throughflow, in a Bryan-Cox model of the Pacific and Indian Oceans. We assign specific causes, in definite locations, to departures from the original version of the rule. Some of these causes can be tested observationally. If Australasia's northern tip is taken at the equator, then in the original version of the rule the throughflow magnitude can be calculated as follows. (1) Everywhere along the standard Island Rule path from Chile to Australasia's southern tip, via the equatorial Pacific, the long-path gradient ∂ P/∂ l of depth-integrated steric height (DISH) P is given by the long-path wind stress τl divided by density ρ and gravitational acceleration g. (2) The Indonesian Throughflow is the sum of the geostrophic flow balancing the resulting DISH difference ΔP between Chile and southern Australasia and the northward Ekman transport between Chile and Australasia. (Corrections for the pressure difference across New Zealand; for flows through Bass, Torres, and Bering Straits; for pressure gradients at the sill depth; and for the Pacific-wide vertical transport W through the sill depth are all treated here as effects omitted from the original version, as are all nonlinear and frictional contributions.) In the model, Torres and Bering Straits were closed and Tasmania was submerged, so the flows through minor straits were all zero. Local balance of wind stress by the DISH gradient worked well along the South American coast and along the western coast of Australasia north of 20°S. In particular, no large frictional components developed near the eastern side of the narrow Indonesian gap. Lateral friction and nonlinearity introduced quite large contributions across the equatorial Pacific, though they largely cancelled one another. However, major departures from the balance assumed in the Island Rule (relative to the sill depth, 629 m in our model) occurred along south western and southern Australia, owing to substantial longshore pressure gradients at the sill depth. These longshore pressure gradients appear to drive the model's Leeuwin Undercurrent. There was also a moderate Coriolis contribution from net outflow near Cape Leeuwin that is supplied by upwelling along Australia's south coast. These effects combined to reduce the model's value of ΔP to 34.6 m2, well below the Island Rule value of 60.4 m2. However, the corresponding depth-integrated pressure (DIP) difference was very close to the original value, because pressure gradients at sill depth largely compensated for the reductions in DISH. The pressure difference across New Zealand was not small; it took 1.0 Sv away from the original estimate. Pacific-wide upwelling W through sill depth was −0.5 Sv, and departures from geostrophy across the South Pacific contributed 0.1 Sv. It was also found that the DIP difference calculated around the direct and indirect routes from Chile to Australasia differed by 3.8 m2, an indication of the model's inability to precisely close the pressure integral over long, closed paths that follow complex topography. Several of these correction terms cancelled, so that the full model value of the throughflow (9.5 Sv; 1 Sv = 106 m3 s−1) was not very different from the original value. This was 10.5 Sv for the wind and topography of our model.

Abstract: : The shock capturing properties of the axisymmetric Euler throughflow equations in design mode (imposed swirl) and in analysis mode (imposed flow angle) are examined through formulation of the Rankine-Hugoniot relations. A new, hybrid mode is constructed that combines properties of the two classical modes. The consequences of the different shock representation in the several modes are illustrated for five characteristic operating points covering the complete design speed performance curve of a transonic axial compressor rotor. Circumferentially averaged 3D Navier-Stokes solutions serve as a reference. A comprehensive comparison of the throughflow and averaged 3D flow fields is presented. The analysis mode, due to captured shocks, predicts a wrong flow field inside the blade passage, yet is reasonably accurate globally. The design and hybrid modes, due to identical shock capturing properties, give near-identical solutions, which are in excellent agreement with the pitch-averaged 3D reference solutions.

Abstract: Two three-dimensional Reynolds-averaged Navier-Stokes solutions of the Nasa 67 transonic compressor rotor with tip clearance, computed at near-peak efficiency and near-stall flow conditions, have been circumferentially averaged in order to evaluate the circumferential spatial fluctuation terms such as u′u′, u′v′, u′w′, etc. The three-dimensional distribution of these fluctuations is presented and physically interpreted for the two flow conditions. Then, the meridional distributions of the tangential average of each of these fluctuation terms, the so-called perturbation stresses, are described and interpreted for the two flow conditions. A meridional throughflow computation for which all stresses were included has been performed for the near-peak efficiency flow condition using a time-marching finite-volume solver. The calculation proved to be in good agreement with the tangentially averaged 3D solution. Moreover, the relative importance of the perturbation and viscous stresses has been investigated. The influence of the viscous stresses on the meridional flow was not found important whereas the perturbation stresses were identified as significant contributors to the blade passage losses and to the spanwise mixing phenomenon. Furthermore, the relative effects of each perturbation term on the meridional flow prediction have been investigated for the near-peak efficiency case. The Display Formulau′w′~, Display Formulav′w′~, Display Formulau′v′~ and Display Formulau′u′~ stresses proved to exert a significant influence on the prediction of blade design key parameters such as flow angles and losses in the tip region, essentially.Copyright © 1999 by ASME

Abstract: The effect of throughflow and Coriolis force on convective instabilities in micropolar fluid layer heated from below for free‐free, isothermal and micro‐rotation free boundaries is investigated. Calculations are made using a lower order Galerkin approximation to solve the eigenvalue problem for stationary instability. It is observed that both stabilizing and destabilizing factors due to constant vertical throughflow can be enhanced by rotation.

Abstract: A three-dimensional, primitive equation ocean circulation model (Wang and Ikeda[7]), was applied to Prince William Sound, Alaska (3D-PWS model) under forcing of freshwater runoff of a line source, heat flux, Gulf of Alaska (GOA) water inflow/outflow (throughflow), and daily (synoptic), spatially varying winds. The 3-D structures and seasonal cycles of the circulation patterns, temperature, salinity, and density were examined in real bottom topography. The river/lake' scenarios (i.e., the weak versus strong flushing throughflow) were captured on a monthly basis. The freshwater runoff of the line source significantly contributes to the basin-scale cyclonic circulation which can't be seen in previous simulations without freshwater runoff (Mooers and Wang [31). Wind forcing due to the orographic effect substantially contributes to the circulation patterns in the Sound. Multiple circulation regimes (cyclonic, anticyclonic, and their combination) characterize the complexity of the system which depends on the intensity of the GOA water throughflow, freshwater discharge of the line source, and the synoptic wind. A winter circulation is characterized by a high flushing regime due to high throughflow and northeast winds, while the spring pattern is dominated by a basin-scale anticyclonic gyre. The summer (July to September) circulation is controlled by a basin-scale cyclonic gyre due to the maximum freshwater influence along the coastline. The autumn circulation is driven by a combination of the throughflow and the northeast wind-driven flow. The simulated cyclonic gyre in summer and late fall is supported by observations.

Abstract: Involves switching one or more heating bodies through in half waves before characteristic power of one body and total power of heating bodies are reached

Abstract: The pipe conduits in the connecting area for a heating body or for water outflow fittings has branch connections In a connecting area a connecting module is provided which has throughflow channels (12,13) with connections on both sides for the pipe conduits The connecting module has branch connections running crossways to its throughflow channels and connected to one of the throughflow channels The branch connections are for a heating body or for outflow fittings The branch connections are connected with the throughflow channels via connecting channels within the intermediate wall area (19) between the two throughflow channels The branch connections run preferably at right-angles to the throughflow channels

Abstract: This work presents a calculation routine for the prediction of the aerodynamic loss of axial flow turbines with coolant injection, which can be easily incorporated into throughflow calculat...

Abstract: The aim of this paper is to contribute to our understanding of the three-dimensional viscous flow in the NASA Large Scale Centrifugal Compressor (LSCC) impeller with vaneless diffuser. An advanced Navier-Stokes solver, EURANUS/TURBO is applied with a linear κ-e model for closure. The computations were performed, at the design speed, at different tip gap sizes and with different grids for both design and off-design flow conditions, while detailed analysis is presented for the design flow condition. An excellent agreement is obtained for most of the data over a wide region of the flow passage. Tip clearance and mesh effects are addressed in the comparisons with the experimental data and some of the mechanisms leading to the formation of the throughflow wake and the 3D flow structure are analyzed.

Abstract: In order to be able to realize especially high live-steam parameters (i.e. live-steam temperatures and live-steam pressures) in a steam turbine, an admission section of the turbine casing which has a number of throughflow openings and is intended for a valve casing for control valves, has a sealing surface which encloses each of the throughflow openings. For an especially reliable seal, a high surface pressure is achieved in the sealing-surface region owing to the fact that an outer contour of the sealing surface is shaped so as to be constricted in the region between adjacent throughflow openings and that, screws of different dimensions are expediently disposed along the constricted outer contour.

Abstract: A three-dimensio nal, primitive equation ocean circulation model (Wang and Ikeda[7]), was applied to Prince William Sound, Alaska (3D-PWS model) under forcing of freshwater runoff of a line source, heat flux, Gulf of Alaska (GO A) water inflow/outflow (throughflow), and daily (synoptic), spatially varying winds. The 3-D structures and seasonal cycles of the circulation patterns, temperature, salinity, and density were examined in real bottom topography. The "river/lake" scenarios (i.e., the weak versus strong flushing throughflow) were captured on a monthly basis. The freshwater runoff of the line source significantly contributes to the basin-scale cyclonic circulation which can't be seen in previous simulations without freshwater runoff (Mooers and Wang [3]). Wind forcing due to the orographic effect substantially contributes to the circulation patterns in the Sound. Multiple circulation regimes (cyclonic, anticyclonic, and their combination) characterize the complexity of the system which depends on the intensity of the GOA water throughflow, freshwater discharge of the line source, and the synoptic wind. A winter circulation is characterized by a high flushing regime due to high throughflow and northeast winds, while the spring pattern is dominated by a basin-scale anticyclonic gyre. The summer (July to September) circulation is controlled by a basin-scale cyclonic gyre due to the maximum freshwater influence along the coastline. The autumn circulation is driven by a combination of the throughflow and the northeast wind-driven flow. The simulated cyclonic gyre in summer and late fall is supported by observations.

Abstract: The heater has terminals for connecting individual U-shaped heating elements (3). The terminals are positioned at a plate (2) at one end of the housing (1). Inlet (4) and outlet spigots are provided to enable water flow through a path (7) inside the housing. Flow and over temperature sensors may be provided.

Abstract: The throughflow sensor or water switch has a housing with a throughflow channel (9) of reduced cross-section and an internal vol. (17) divided into two chambers by a membrane (18). The chambers communicate with the throughflow channel via control channels (37,41). A magnet mounted on the membrane is positioned by the membrane. A sensor element (66) mounted outside the internal vol. reacts to displacements of the magnet.