scholarly journals Die invloed van nate op die loop van die Oranjerivier in die omgewing van die Augrabieswaterval Nasionale Park

Koedoe ◽  
1983 ◽  
Vol 26 (1) ◽  
Author(s):  
M. J Slabbert ◽  
S. J Malherbe
Keyword(s):  
Flow Pattern ◽  
National Park ◽  
Main Flow ◽  
Lattice Type ◽  
Type Flow ◽  
Flow Directions ◽  
Geomorphological Features

wee duidelike, bykans vertikale noord- en ooswaarts- neigende naatstelsels is goed ontwikkel dwarsdeur die Augrabieswaterval Nasionale Park. Die twee hoofvloeirigtings van die rivier stem ooreen met die orientasie van die naatstelsels. Die tralievormige vioeipatroon van die rivier kan hiervolgens verklaar word. Hierdie nate tesame met ondergeskikte nate en verskuiwings kan ook sekere geomorfologiese verskynsels in die park verklaar. Two distinct, near-vertical, north- and east-trending joint sets are well developed throughout the Augrabies Falls National Park. The two main flow directions of the river are in accordance to the orientation of these joints. The lattice-type flow pattern of the river can therefore be explained by their influence. These joints together with subordinate joints and faults could explain some of the geomorphological features within the park.

Numerical analysis of the groove effect on the tip leakage vortex cavitating flow

2019 ◽  
Vol 234 (6) ◽  
pp. 836-847
Author(s):  
Zhaodan Fei ◽  
Rui Zhang ◽  
Hui Xu ◽  
Tong Mu
Keyword(s):  
Flow Pattern ◽  
Flow Characteristics ◽  
Cavitating Flow ◽  
Main Flow ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Curvature Effects ◽  
The Mean

In this paper, the groove effect on the tip leakage vortex cavitating flow characteristics of a simplified NACA0009 hydrofoil with tip gap is studied. Considering local rotation characteristics and curvature effects of the tip leakage vortex flow, the rotation-curvature corrected shear-stress-transport turbulence model is applied to simulate the time-averaged turbulent flow. The Zwart–Gerber–Belamri cavitation model is used to simulate the cavitating flow. The results show that the groove could affect the tip leakage vortex cavitating flow. The groove enhances the interaction between the tip leakage flow and main flow, and then it affects the cavitation of the tip leakage vortex. Compared with the non-groove case, for groove cases of αgre ≤75°, the tip leakage vortex cavitating flow is suppressed, the flow pattern in the gap is improved, and the mean leakage velocity Vlk < 0.8. The region of high leakage velocity is eliminated and the distribution of the pressure is more uniform. The tip leakage vortex cavitation area is reduced, and the maximum decrease is 72.90%. While for groove cases of αgre≥90°, neither the tip leakage vortex cavitating flow nor flow pattern in the tip gap is ameliorated, the mean leakage velocity Vlk lies the range from 0.90 to 0.96. The region of high leakage velocity still exists and even the tip leakage vortex cavitation area is increased. Based on three-dimensional streamlines and vorticity transport equation, the interaction between the tip leakage flow and main flow leads to the variation of the tip leakage vortex cavitating flow. This paper aims for a useful reference to mitigate the tip leakage vortex cavitation and control the influence of the tip leakage vortex cavitating flow for the hydraulic machinery.

scholarly journals STUDY AND ANALYSIS OF SILTATION AT NAHRE GHASR FISHERY PORT

2017 ◽  
pp. 36
Author(s):  
Mehrdad Orooghi Amidi ◽  
Mohsen Soltanpour ◽  
Zahra Ranji
Keyword(s):  
Flow Pattern ◽  
Suspended Sediment ◽  
Persian Gulf ◽  
Water Surface ◽  
Numerical Models ◽  
Dominant Role ◽  
Measured Data ◽  
Main Flow ◽  
Flow Mechanisms ◽  
The Persian Gulf

The discharge of Arvand River and tidal currents affect the large siltation at Nahre Ghasr Fishery Port, located at the Nahre Ghasr channel, the Persian Gulf. Using 2DH and 3D numerical models, the flow pattern at the channel was investigated to study the details of siltation problem. The local model was calibrated by the measured data of water surface and suspended sediment rate. The main flow mechanisms that can affect the rate of siltation including the horizontal exchange, the vertical exchange and tidal filling, were analyzed. The study showed that tidal filling plays the dominant role on the sedimentation at Nahre Ghasr channel. Different scenarios were also examined for reducing the siltation rate at the port.

scholarly journals Modification of Planetary Mixer with Strainer Arrangement

2021 ◽  
Author(s):  
Mahesh Chavan ◽  
Dnyaneshwar Kapase ◽  
Manish Parachande ◽  
Shambhu Hingmire ◽  
Mahesh Gund ◽  
...  
Keyword(s):  
Flow Pattern ◽  
Vortex Formation ◽  
Poor Quality ◽  
Main Flow ◽  
Specific Flow ◽  
Spiral Path ◽  
Equivalent Time ◽  
Conventional Machine ◽  
Fixed Axis ◽  
Metal Oxide Powder

The stirrer of conventional machine rotates in one direction only which creates a specific flow pattern within the fluids hence the particles tend to stay to the walls of container owing to the force instead of mixing thoroughly in mixture of paint, ultimately results into poor quality mixture of paints there by poor quality output of paint . In order to possess a through mixing of metal oxide powder it might be appropriate to possess a stirrer that rotates such rotates about own axis also revolves about another fixed axis which helps it reach all parts of the container. This ensures that turbulence required for thorough mixing is provided all over the container. It would be advantageous to vary pattern of flow, which avoids vortex formation, i.e. motion of particles in a spiral path. Also if a wiper is added that brings the particles adhering to walls of container back to main flow or mixing area, good quality mixture are going to be ensured. The planetary mixer with strainer may be a perfect solution that has all the above mentioned features. This machine involves a rotating stirrer that revolves about the fixed container axis also as incorporates an strainer that changes the flow pattern and also acts as a wiper. Machine has variable mixing speed feature at an equivalent time delivers heavy torque to the stirrer for proper mixing.

scholarly journals Numerical Investigation of Flow Characteristics of Molten Steel in the Tundish with Channel Induction Heating

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1937
Author(s):  
Bin Yang ◽  
Hong Lei ◽  
Yingshi Xu ◽  
Kun Liu ◽  
Peng Han
Keyword(s):  
Fluid Flow ◽  
Flow Pattern ◽  
Numerical Investigation ◽  
Induction Heating ◽  
Molten Steel ◽  
Flow Behavior ◽  
Plug Flow ◽  
Flow Characteristics ◽  
Main Flow ◽  
Mixed Flow

In the continuous process, fluid flow is an important physical phenomena in the tundish, as it affects the process of heat transfer, bubble motion and inclusion collision-coalescence and grow up. This paper undertakes a detailed numerical investigation of fluid flow characteristics in the tundish with and without induction heating. The individual unit method and the volume subtraction model are applied to analyze the flow characteristics. A quantitative evaluation method of flow characteristics is proposed to investigate the flow characteristics. In the tundish with and without induction heating, firstly, the main flow behavior of molten steel is mixed flow in the receiving chamber; secondly, the main flow behavior of molten steel is plug flow in the channel; lastly, the main flow pattern is mixed flow, and the minor flow pattern is plug flow in the discharging chamber. The method of the volume subtraction model is an effective way to analyze the flow characteristics in the tundish with channel induction heating.

Flow separation at the upstream edge of a square-edged broad-crested weir

1972 ◽  
Vol 52 (2) ◽  
pp. 307-320 ◽  
Author(s):  
W. D. Moss
Keyword(s):  
Simple Model ◽  
Flow Pattern ◽  
Turbulent Mixing ◽  
Separation Bubble ◽  
Surface Profile ◽  
Main Flow ◽  
Mixing Zone ◽  
Flow Mechanism ◽  
Complex Character ◽  
Static Head

A simple model is suggested to explain the flow mechanism at the upstream edge of a square-edged broad-crested weir. The separation bubble that may be seen to occur at this point is treated as an area of constant static head, while the main flow outside the bubble is deemed to be irrotational and divided from the bubble by a free streamline. If this model is accepted, the flow pattern will be such that energy requirements will be met along the free surface and the streamline bounding the bubble while, within these boundaries, the Laplace equation will be satisfied at every point. Accordingly, a solution satisfying these conditions is established by the use of a relaxation technique.In practice, it is likely that the cavity flow within the bubble will be bounded not by a single streamline but by a turbulent mixing zone and that there will be some increase in pressure near the point of re-attachment. Nevertheless, the surface profile and flow pattern observed in experiments show fair agreement with those predicted using the simple model. Whilst acknowledging, then, that the bubble and the zone bounding it are in fact of a more complex character, we may say that this simplified treatment affords a sound model of the main flow and so permits a better understanding of the action of the square-edged broad-crested weir.

Swirling Impeller Flow

1988 ◽  
Vol 110 (1) ◽  
pp. 122-128 ◽  
Author(s):  
H. Krain
Keyword(s):  
Velocity Profile ◽  
Flow Pattern ◽  
Theoretical Approach ◽  
Vortex Flow ◽  
Swirling Flow ◽  
Secondary Flows ◽  
Laser Measurements ◽  
Measurement Results ◽  
Type Flow ◽  
Relative Flow

The results of extensive laser measurements carried out in the blade passages of a newly designed backswept impeller are presented and discussed. Noticeable distortions of the throughflow patterns and a distinct swirling flow character were found inside the rotor. The measurement results and a simple theoretical approach suggest that the distorted throughflow patterns and the secondary flows are caused by a vortex flow. Although the relative flow has been significantly decelerated a comparatively smooth velocity profile has been identified at the rotor discharge that differed widely from the well-known jet/wake-type flow pattern.

On the Main Flow Pattern in Hydrocyclones

1993 ◽  
Vol 115 (1) ◽  
pp. 21-25 ◽  
Author(s):  
C. C. Hwang ◽  
H. Q. Shen ◽  
G. Zhu ◽  
M. M. Khonsari
Keyword(s):  
Theoretical Model ◽  
Flow Field ◽  
Closed Form ◽  
Flow Pattern ◽  
Main Flow ◽  
Experimental Measurements ◽  
Main Body ◽  
Governing Equations ◽  
Adequate Representation ◽  
Good Agreement

A theoretical model is developed for the prediction of the main flow pattern in hydrocyclones. The model regards the main body of the cyclone as inviscid and includes provisions for the fluid underflow in cyclones. The governing equations are solved analytically in closed form. To verify the results, a laboratory-scale conically-shaped hydrocyclone was designed, built, and tested. Experimental measurements for axial and tangential velocities are presented with a series of tests solely devoted to the effect of underflow. The theoretical and experimental results are shown to be in good agreement. It is concluded that such an inviscid model gives an adequate representation of the main flow field in a cyclone.

scholarly journals Secondary Flows and Vortex Motion in a High-Efficiency Backswept Impeller at Design and Off-Design Conditions

1989 ◽  
Author(s):  
C. Hah ◽  
H. Krain
Keyword(s):  
Flow Pattern ◽  
High Efficiency ◽  
Pressure Ratio ◽  
Vortex Motion ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Optimum Shape ◽  
Discharge Velocity ◽  
Type Flow

The 3-D viscous flowfield of a 4.7:1 pressure ratio backswept impeller was studied experimentally and numerically by using laser velocimetry and an advanced 3-D viscous code. The impeller was designed by a CAD method, and a maximum rotor efficiency of 94% was achieved. Both the experimental and the theoretical approach revealed comparatively smooth impeller discharge velocity profiles at all three operating conditions (design, choke, and near surge) differing widely from the well-known jet/wake type flow pattern. The 3-D viscous code was used for detailed flowfield studies, i.e., secondary flows; vortex motion and tip-clearance effects were analyzed at design and off-design conditions. The comparison of experimental and numerical results indicates that the tip-clearance effect should be properly modeled to predict the impeller flow pattern properly and that optimum shape of rotor exit flow pattern can be obtained by controlling the swirling vortex motion.

scholarly journals Integrating Geoheritage into the Management of Protected Areas: Proposal for the Itatiaia National Park, Brazil

2021 ◽  
Author(s):  
Vanessa Costa Mucivuna ◽  
Maria da Glória Motta Garcia ◽  
Emmanuel Reynard ◽  
Pedro Augusto da Silva Rosa
Keyword(s):  
Protected Areas ◽  
National Park ◽  
Management Plan ◽  
International Union ◽  
Management Plans ◽  
Geomorphological Features ◽  
Conservation And Management

Abstract The International Union for Conservation of Nature (IUCN) has created many initiatives to integrate geodiversity and geoheritage into the management of protected areas through a broader concept of nature. Many protected areas, however, do not have an inventory of geoheritage sites. In view of this fact, this study aims to discuss the geoheritage inventory and to analyse, through a case study, how geodiversity is described in an existing management plan, prepared before IUCN included geoheritage in the Manual for the Management of Protected Areas. This study was conducted in the Itatiaia National Park, which has outstanding geological and geomorphological features. To ensure appropriate assessment of geological sites (including geomorphological, hydrological, petrological, sedimentary, structural sites, etc.), we took inventory of geoheritage and then analysed how the management plan addresses geodiversity. The geoheritage inventory includes 17 geosites distributed in six geological frameworks, seven geodiversity sites and three viewpoints. We concluded that although geodiversity is mentioned in the plan, the geoheritage inventory would facilitate and support the exploration of management possibilities that range from protection to education. Therefore, we recommend the inclusion of geoheritage inventory in the management plans of protected areas because it is a valuable tool for the proper conservation and management of geoheritage.

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