Abstract: Soil water potentials, slope throughflow, runoff chemistry, and isotopic composition were monitored in a 97 m2 zero-order basin within the Maimai 8 watershed on the South Island of New Zealand, for a natural rain storm and two artificial water applications. Contrary to results previously reported for other portions of the Maimai catchment, much of the runoff occurred as a shallow subsurface organic layer flow. For the 47 mm natural rain event, pre-storm soil matric potential ranged from −60 to −150 cm H2O. No saturation was produced within the profile, and the majority of storm runoff emanated from flow within the organic horizon perched on the mineral soil surface. Hillslope applications corroborated this interpretation by showing >90 percent new water flushing with negligible mineral soil moisture response. Although the mechanisms cited in the text are not representative of the entire catchment, the study demonstrates: (1) the value of a combined physical-chemical-isotopic approach in quantifying slope processes, and (2) the heterogeneous nature and diversity of slope runoff pathways in a relatively homogeneous catchment.

Abstract: We implement a linear stability analysis of the convective instability in superposed horizontal fluid and porous layers with throughflow in the vertical direction. It is found that in such a physical configuration both stabilizing and destabilizing factors due to vertical throughflow can be enhanced so that a more precise control of the buoyantly driven instability in either a fluid or a porous layer is possible. For ζ = 0.1 (ζ, the depth ratio, defined as the ratio of the fluid-layer depth to the porous-layer depth), the onset of convection occurs in both fluid and porous layers, the relation between the critical Rayleigh number Rcm and the throughflow strength γm is linear and the Prandtl-number (Prm) effect is insignificant. For ζ ≥ 0.2, the onset of convection is largely confined to the fluid layer, and the relation becomes Rcm ∼ γ2m for most of the cases considered except for Prm = 0.1 with large positive γm where the relation Rcm ∼ γ3m holds. The destabilizing mechanisms proposed by Nield (1987 a, b) due to throughflow are confirmed by the numerical results if considered from the viewpoint of the whole system. Nevertheless, from the viewpoint of each single layer, a different explanation can be obtained.

Abstract: The western tropical Pacific is thought to be an important zone for generating El Nino: reflections at the boundary make it a source region of equatorial Kelvin waves. Calculations of the effect of a gappy western boundary on the reflection process are carried out in the framework of the low-frequency limit of the shallow-water equations and thus are highly idealized. The method is also applied to a schematic version of the flow through the Indonesian seas from the western Pacific to the Indian Oceans. The results indicate some strong sensitivities to the location of the gap and to the structure of the incoming flows. In addition, the results can be quite different, depending on whether the zonal extend of the gap is assumed to be infinite or finite. (More precisely, the latter means that the extend of the gap is short compared with the zonal wavelength of the relevant free waves at that frequency.) In view of the complexity of the results for even such a simplified model, it will be very difficult to be confident of any modeling study of the Indonesian throughflow short of a highly resolved numerical calculation with a detailed representation of the geometry and bathymetry. Nonetheless, we offer tentative conclusions concerning the efficiency of the western Pacific boundary as a reflector. Our results suggest that the realistic boundary will not greatly alter expectations based on a simple solid boundary if the reflections important for El Nino are primarily in motion, represented by low-order Rossby modes. This is also consistent with observational evidence indicating no anomalous throughflow during El Nino events.

Abstract: A physically-based rainfall-runoff model is used to investigate effects of moving storms on the runoff hydrograph of throughflow dominated idealised catchments. Simulations are undertaken varying the storm speed, direction, intensity, the part of the catchment affected by rainfall, and the spatial definition of rainfall zones. For a 100 km2 catchment, under the circumstances investigated, an efficient spatial resolution of rainfall data is around 2.5 km along the path of the storm. Storms moving downstream produce earlier, higher peaks than do storms moving upstream. Error is most likely to be introduced into lumped-rainfall predictions for slower storm speeds, and the likely direction of this error can be specified. Differences in magnitude of peak response between downstream and upstream storm directions reach a maximum at a storm speed and direction similar to the average peak channel velocity. These results are qualitatively similar to those reported for overland flow dominated catchments, but differences in peak runoff between downstream and upstream storm directions are much smaller where rainfall inputs are modified by a period of hillslope throughflow.

Abstract: Local and average heat transfer coefficients were measured for a confined turbulent slot jet impinging on a permeable surface at which there may be throughflow. Local Nusselt number was obtained using a unique porous sensor designed for measurement of local heat transfer at a permeable surface which is subjected to rapidly and widely varying heat transfer. Measurements were performed for a wide range of jet Reynolds number and throughflow rates. Convective heat transfer coefficients was found to be enhanced by throughflow, and the enhancement factor in terms of Stanton number to be independent of jet Reynolds number and of extent of heat transfer area. Les coefficients de transfert de chaleur locaux et moyens ont ete mesures pour un jet-fente turbulent confine impac-tant sur une surface permeable pouvant avoir un ecoulement traversant. On a obtenu le nombre de Nusselt au moyen d'un capteur poreux unique concu pour mesurer le transfert de chaleur local sur une surface permeable sujette a un transfert de chaleur variant de facon rapide et importante. Les mesures ont ete obtenues pour une large gamme de nombres de Reynolds du jet et de vitesses d'ecoulement traversant. On a trouve que les coefficients de transfert de chaleur con-vectif augmentaient avec l'ecoulement traversant et que le facteur d'accroissement en termes de nombre de Stanton etait independant du nombre de Reynolds du jet et de l'extension de la surface du transfert de chaleur.

Abstract: Flow and heat transfer under confined turbulent impinging slot jets were predicted by solving iteratively the two-dimensional Navier-Stokes, energy, and turbulence model equations. The turbulence model was the highReynolds-number version of the well-known A>e model. Recent work has shown that a modification of the Chieng-Launder-type near-wall model gives better agreement with measurements at small nozzle-to-surface spacings, H/w < 2.6. The predictive capability of this model was therefore tested for the effects of nozzle-exit turbulence and of impingement surface throughflow for a single jet and for the industrially important system of confined multiple jets with symmetrical exhaust ports, with and without throughflow. The model underpredicts the enhancement of heat transfer with increasing nozzle-exit turbulence but accurately predicts the effect of impingement surface throughflow for throughflow velocities less than 0.1 m/s. Heat transfer under multiple jets was predicted within 30% of the experiments.

Abstract: The arrangement for measuring the viscosity of liquids contains a throughflow vessel (1) with temp. controlled heating (3) and is associated with a throughflow time measurement. A light barrier (8) associated with the outlet (9) of the vessel is used to control a time counter. The opening of the throughflow vessel can be opened depending on a lifting magnet (11) activated at a predefined temp.. The vessel can have an overflow and a light barrier level monitoring arrangement. USE/ADVANTAGE - E.g. for monitoring viscosity of oil e.g. for hydraulic press. Eliminates certain inaccuracies associated with conventional ones, thus reducing number of unnecessary oil changes.

Abstract: A closure device for a molten metal vessel is to be configured in such a way that solidified melt zones are carried away through the throughflow channel (7) during the initial casting process. For this purpose, the cross-section of flow of the throughflow channel (7) widens from an inlet opening (8) in the melt to an outlet opening (12). … …

Abstract: Flow visualization studies of a lid‐driven cavity (LDC) with a small amount of throughflow reveal multiple steady states at low cavity Reynolds numbers. These results show that the well‐known LDC flow, which consists of a primary eddy and secondary corner eddies, is only locally stable, becomes globally unstable, and competes with at least three other steady states before being replaced by a time‐periodic flow. The small amount of throughflow present in this system seems to have no qualitative effect on the fluid flow characteristics. These observations suggest that multiple stable steady states may also exist in closed LDC’s. Since stability properties of the closed LDC flows are virtually unexplored, we interpret our flow visualization results by first proposing an expected behavior of an idealized (free‐slip end walls) LDC and then treating the problem at hand as a perturbation of the ideal case. The results also suggest that there are nonunique and competing sequences of transitions that lead the flow in a LDC from laminar steady state toward turbulence.