scholarly journals Topographic influence on the pattern of flow through Bass Strait

1995 ◽  
Vol 46 (4) ◽  
pp. 763 ◽  
Author(s):  
PG Baines ◽  
DL Murray
Keyword(s):  
Flow Pattern ◽  
Physical Model ◽  
Potential Vorticity ◽  
Laboratory Simulation ◽  
Eastern Region ◽  
Constant Depth ◽  
The West ◽  
Flow Through ◽  
Southern Branch ◽  
Topographic Influence

A laboratory simulation of the flow through Bass Strait has been made with the aid of a physical model of the topography, situated in a tank on a rotating turntable. The throughflow was driven by a continuous supply of homogeneous water to the western end that was uniform with latitude. The effect of the depth variations within the strait were realistically represented and had a controlling influence on the flow pattern. In particular, the uniform inflow from the west was directed towards the south-eastern region, guided along contours of constant depth around the central depression by approximate conservation of potential vorticity. West of Flinders Island, the flow then splits into a northward branch that flows toward the Victorian coast and leaves the strait near Gabo Island and a southern branch that leaves through Banks Strait. This modelled flow pattern is generally consistent with the outflows inferred from observed temperature and salinity fields.

Managing rivers for conservation and ecotourism in the Kruger National Park

1995 ◽  
Vol 32 (5-6) ◽  
pp. 227-233 ◽  
Author(s):  
F. J. Venter ◽  
A. R. Deacon
Keyword(s):  
National Park ◽  
Good Condition ◽  
Kruger National Park ◽  
Rapid Expansion ◽  
Natural Environments ◽  
The West ◽  
The Past ◽  
Management Actions ◽  
Flow Through ◽  
Three Rivers

Six major rivers flow through the Kruger National Park (KNP). All these rivers originate outside and to the west of the KNP and are highly utilized. They are crucially important for the conservation of the unique natural environments of the KNP. The human population growth in the Lowveld during the past two decades brought with it the rapid expansion of irrigation farming, exotic afforestation and land grazed by domestic stock, as well as the establishment of large towns, mines, dams and industries. Along with these developments came overgrazing, erosion, over-utilization and pollution of rivers, as well as clearing of indigenous forests from large areas outside the borders of the KNP. Over-utilization of the rivers which ultimately flow through the KNP poses one of the most serious challenges to the KNP's management. This paper gives the background to the development in the catchments and highlights the problems which these have caused for the KNP. Management actions which have been taken as well as their results are discussed and solutions to certain problems proposed. Three rivers, namely the Letaba, Olifants and Sabie are respectively described as examples of an over-utilized river, a polluted river and a river which is still in a fairly good condition.

Upward Vertical Two-Phase Flow Through an Annulus—Part II: Modeling Bubble, Slug, and Annular Flow

1992 ◽  
Vol 114 (1) ◽  
pp. 14-30 ◽  
Author(s):  
E. F. Caetano ◽  
O. Shoham ◽  
J. P. Brill
Keyword(s):  
Flow Pattern ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Flow Behavior ◽  
Bubble Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Through ◽  
Physical Phenomena ◽  
Good Agreement

Mechanistic models have been developed for each of the existing two-phase flow patterns in an annulus, namely bubble flow, dispersed bubble flow, slug flow, and annular flow. These models are based on two-phase flow physical phenomena and incorporate annulus characteristics such as casing and tubing diameters and degree of eccentricity. The models also apply the new predictive means for friction factor and Taylor bubble rise velocity presented in Part I. Given a set of flow conditions, the existing flow pattern in the system can be predicted. The developed models are applied next for predicting the flow behavior, including the average volumetric liquid holdup and the average total pressure gradient for the existing flow pattern. In general, good agreement was observed between the experimental data and model predictions.

A short note on Chinae Hans Muscuovy ducks in Bengal, India

2003 ◽  
Vol 33 ◽  
pp. 93-95 ◽  
Author(s):  
S. Banerjee ◽  
S. Banerjeel
Keyword(s):  
West Bengal ◽  
Short Note ◽  
Poultry Meat ◽  
Eastern Region ◽  
The West ◽  
Free Range ◽  
Cairina Moschata ◽  
Mule Duck

SummaryMuscuovy ducks (Cairina moschata) are popular as a source of poultry meat. Reports on availability of Muscovies (in the free range system of management) in the eastern region of Indu is lacking. In the West Bengal state of Indu two strains of Muscovies have been identified, the strains resemble Black Muscuovy L 303 and White Muscuovy ducks. Ironically they are known as Chinae haras (Chinese duck). Presently a detailed study is being conducted by the author and is being used to develop a strain of broader duck (mule duck) in the region. Reports on availability of Muscovies in this part of the subcontinent are lacking.

Using reflection seismic method to estimate the fluid dynamics parameters related to wakes

2021 ◽  
Author(s):  
Wenhao Fan ◽  
Haibin Song ◽  
Kun Zhang ◽  
Yi Gong ◽  
Shun Yang ◽  
...  
Keyword(s):  
Potential Vorticity ◽  
Negative Potential ◽  
Distribution Area ◽  
The West ◽  
West Side ◽  
Reflection Seismic ◽  
Vorticity Distribution ◽  
Positive Vorticity ◽  
Coherent Vortices ◽  
Survey Line

<p>In this study, when using reflection seismic data to study the wakes of the Batan Islands, a method for estimating the fluid dynamics parameters such as the relative vorticity (relative Rossby number) and the relative potential vorticity is proposed. Although the relative Rossby number estimation method proposed in this study cannot guarantee absolute accuracy in the calculation value, this method is more accurate in describing the positive and negative vorticity distribution for the wakes, and the resolution of the positive and negative vorticity distribution described by this method is higher than the result of the reanalysis data. For the wakes developed in the Batan Islands, the reflection events in the wake development area have the larger inclination than the reflection events in the western Pacific water distribution area. It is also found that the negative vorticity wakes are mainly distributed on the west side of the island/ridge, and the positive vorticity wakes are mainly distributed on the east side of the island/ridge. This is consistent with the understanding of previous wakes simulations. The strong vorticity values in the study area are mainly distributed at depths above 300m, and the maximum impact depth of wakes can reach 600m. At the downstream position of the wake on the survey line 7, it can be seen that the bottom boundary layer has separated, and there is the negative vorticity wakes on the west side intruding into the positive vorticity wakes on the east side , which is presumed to be caused by the disturbance of the small anticyclone existing near the Batan Islands. For the survey line 7, the negative potential vorticity is mainly distributed on the west side of the island/ridge, and the influence range can reach the sea depth of 600m. In the negative potential vorticity region, there is strong energy dissipation and vertical shear. In this study, we don’t find the existence of submesoscale coherent vortices on the survey line 7, but find the reflection structure similar to filaments on the seismic section. Combined with the analysis of the balanced Richardson number angle of survey line 7, we speculate that the wake in the negative potential vorticity distribution area has the characteristics of symmetrical instability, and the symmetrical instability may destroy the process of filaments forming submesoscale coherent vortices.</p>

scholarly journals Dynamical Diagnosis: A Comparison of Quasigeostrophy and Ertel Potential Vorticity

2008 ◽  
Vol 55 ◽  
pp. 183-202 ◽  
Author(s):  
John W. Nielsen-Gammon ◽  
David A. Gold
Keyword(s):  
Potential Vorticity ◽  
Vertical Motion ◽  
Geostrophic Wind ◽  
Diagnostic Techniques ◽  
Ensemble Forecasting ◽  
Model Resolution ◽  
The West ◽  
Definition Of ◽  
Improved Model ◽  
The Right

Abstract Advances in computer power, new forecasting challenges, and new diagnostic techniques have brought about changes in the way atmospheric development and vertical motion are diagnosed in an operational setting. Many of these changes, such as improved model skill, model resolution, and ensemble forecasting, have arguably been detrimental to the ability of forecasters to understand and respond to the evolving atmosphere. The use of nondivergent wind in place of geostrophic wind would be a step in the right direction, but the advantages of potential vorticity suggest that its widespread adoption as a diagnostic tool on the west side of the Atlantic is overdue. Ertel potential vorticity (PV), when scaled to be compatible with pseudopotential vorticity, is generally similar to pseudopotential vorticity, so forecasters accustomed to quasigeostrophic reasoning through the height tendency equation can transfer some of their intuition into the Ertel-PV framework. Indeed, many of the differences between pseudopotential vorticity and Ertel potential vorticity are consequences of the choice of definition of quasigeostrophic PV and are not fundamental to the quasigeostrophic system. Thus, at its core, PV thinking is consistent with commonly used quasigeostrophic diagnostic techniques.

scholarly journals TWO REMARKABLE NEW SPECIES OF HUBBARDIIDAE COOK, 1899 (ARACHNIDA: SCHIZOMIDA) FROM EASTERN CUBA

2019 ◽  
Vol 20 ◽  
pp. 40-54
Author(s):  
Rolando Teruel ◽  
Tomás M. Rodríguez-Cabrera
Keyword(s):  
New Species ◽  
The Other ◽  
Eastern Region ◽  
Generic Diagnosis ◽  
The West ◽  
Eastern Cuba

Two new, remarkable species of schizomids are described in the present paper, both from eastern Cuba. One of them is the second known member of Troglocubazomus Teruel, 2003, which allows the redefinition of the generic diagnosis and expands the known range of this genus more than 200 km to the west, but still in the same orographic system (the Sierra Maestra Mountains). The other represents the ninth Cuban member of Antillostenochrus Armas & Teruel, 2002, but the first to be found living here in a desertic habitat (only one Hispaniolan species was previously known to live under the same aridity conditions). As results, the schizomid fauna of Cuba reaches 59 species (58 national endemics), with 39 of them occurring in its eastern region (35 regional endemics).

scholarly journals Investigation of the Modulation of the Tidal Stream Resource by Ocean Currents through a Complex Tidal Channel

2019 ◽  
Vol 7 (10) ◽  
pp. 341 ◽  
Author(s):  
Alice J. Goward Brown ◽  
Matt Lewis ◽  
Benjamin I. Barton ◽  
Gus Jeans ◽  
Steven A. Spall
Keyword(s):  
Tidal Energy ◽  
Resource Assessment ◽  
Tidal Currents ◽  
The West ◽  
Ocean Modelling ◽  
Through Flow ◽  
The World ◽  
Tidal Stream ◽  
Flow Through ◽  
Resource Uncertainty

Tidal energy has the opportunity to bring reliable electricity to remote regions in the world. A resource assessment, including the response of the tidal stream resource to fluctuations in the Indonesian Through Flow (ITF) is performed using the Regional Ocean Modelling System (ROMS) to simulate four different scenarios for flow through the Lombok Strait in Indonesia. Tidal currents simulated with a variable ITF are compared against a tide-only (TO) simulation to identify how the ITF spatially changes the resource across the Lombok Strait. We find that the uncertainty in the tidal currents from the TO simulation is 50% greater than the variable ITF simulation. To identify change to resource, surface velocities from Strong ITF and Weak ITF scenarios are considered. As a result of the fluctuations in the ITF, certain characteristics, such as the asymmetry and magnitude, of the tidal current vary greatly. However, the magnitude of change is variable, with regions to the west of the strait experiencing greater modulation than in the east, suggesting that resource uncertainty can be minimised with selective site positioning.

Numerical simulation and experiment for study on internal flow pattern of vortex pump

2019 ◽  
Vol 36 (5) ◽  
pp. 1579-1596
Author(s):  
Hui Quan ◽  
Yi Chai ◽  
Rennian Li ◽  
Jianhui Guo
Keyword(s):  
Flow Pattern ◽  
Theoretical Foundation ◽  
Internal Flow ◽  
Content Type ◽  
Vortex Pump ◽  
Hydraulic Design ◽  
Through Flow ◽  
Simulation And Experiment ◽  
Flow Through ◽  
Working Out

Purpose The special structure of the vortex pump contributes to its complex internal flow pattern. A type of horizontal 150WX-200-20 vortex pump is taken as a research subject to deeply study the progression and distribution of flow pattern in its channel. To explain the mechanism of flow in this pump, numerical analysis of the whole flow and experiment have been conducted. Design/methodology/approach The authors studied and analyzed the distribution and evolution of flow pattern under different flow, such as circulating-flow, through-flow and other forms. Finally, a model of flow pattern in the vortex pump has been built, which has more perfectly fit the reality. Findings They are through-flow affected by circulating-flow, main and subsidiary circulating-flow, vortices between vanes and other vortices (or liquid impingement) in volute. Entering the pump, part of the flow stays in vanes and turn into vortices while the other goes into the front chamber. The flow that runs into the front chamber will be divided into two parts. One part will be collected by viscosity into a vortex rope when it passing through the interface between the impeller and the vaneless chamber, which closely relates to the circulating-flow, and the rest directly goes out of the field through the diffuser. Besides, a fraction of circulating-flow joins the through-flow when it goes through the section V and leaves the pump. Originality/value The research results build a theoretical foundation for working out the flow mechanism of the vortex pump, improving its efficiency and optimizing its hydraulic design.

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