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Home > Investigation of Various Sediment and Flow Parameters upon Three Dimensional Flow Using Numerical Model

Investigation of Various Sediment and Flow Parameters upon Three Dimensional Flow Using Numerical Model

Thesis Info

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External Link

Author

Ghani, Usman

Program

PhD

Institute

University of Engineering and Technology

City

Taxila

Province

Punjab

Country

Pakistan

Thesis Completing Year

2010

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1814

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726511182

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The aim of this research work was to investigate and increase the understanding of three dimensional flow behavior under changing conditions of flow and sediments. The goal was achieved by using a 3D Computational Fluid Dynamics model FLUENT. The geometry selected for this study is that of a meandering compound channel. The parameters which were changed in this research work include the width of floodplain along with main channel width, overbank flow depth, incoming discharge, bed slope of the main channel and floodplains and roughness of the channel and floodplains. The research work was conducted by using different turbulence models. Among them are standard k - e , Re-normalization Group (RNG) theory based k - e and k - w turbulence models. These three models were applied for one case. Once the capability of k - e model was established after comparison with results of other models, then only k - e was used in the remaining part of the work. The data obtained from a physical model study in the laboratory was used for the validation of simulated results. The validation was done through a comparison of observed and calculated values of depth averaged velocities, total discharge at a section & point velocities. After validation, the CFD model was used to predict and investigate those aspects of flow which were difficult to get through experiments and for which experimentation was not conducted in the laboratory. These aspects include turbulence intensity, turbulent kinetic energy, pressure distribution on different cross sections of the channel and surface velocity magnitudes. As far as the sediments study is concerned, the Lagrangian particle tracking technique was used to predict the changes in bed levels at apex of the meander wavelength. Sediment particles with different diameters were used for this purpose. A total of eight flow cases were considered for the study of flow field. Each case varies from the other on the basis of (i) geometry or (ii) bed slope or (iii) depth of overbank flow or a combination of these. This work also proved the capability of standard k - e turbulence closure models in prediction of 3D overbank flows. Keywords: Sediment transport, CFD modeling, Flood flows, Numerical techniques, Turbulent kinetic energy.
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باب چہارم: معدنی وسائل کا مطالعہ

معدنیات کی اہمیت و افادیت

تعارف(Introduction)

معدنی کا لفظ معدن سے ماخوذ ہے۔ فیروز اللغات میں معدن کے لغوی معنی درج ذیل ہیں:

"کان-کھان- وہ جگہ زمین کھود کر دھاتیں۔ کوئلہ وغیرہ نکالیں۔ (جمع) معادن۔ "[1]

معدنیات کے لغوی معنی "وہ چیزیں جو کان سے نکلیں۔ دھات۔ فلّزات۔ "[2] ہیں۔

معدنیات کو اہم قدرتی وسیلہ کہا جاتا ہے۔ پاکستان معدنیا ت سے مالا مال ملک ہے اس لئے وطن عزیز میں معدنیا ت کے امور طے کرنے کے لئے معدنیات کی وزارت قائم کی گئی ہے۔ معدنیات میں سونا، چاندی، لوہا، تانبا اور نمک وغیرہ شامل ہیں۔ معدنیات کے ذخائر کسی بھی ملک کی ترقی و خوشحالی میں انتہائی مثبت کردار ادا کرتے ہیں۔ مسلم ممالک میں معدنی ذخائر کی بھرمار ہے لیکن ملت اسلامیہ کا المیہ یہ ہے کہ یہ ممالک جدید سائنس و ٹیکنالوجی میں مغربی ممالک کے ہم پلہ نہ ہونے کےباعث اپنے معدنی ذخائر کے اخراج کے لئے ان کے زیر تسلط ہیں۔ جدید ٹیکنالوجی سے لیس ہونا ملت اسلامیہ کے لئے ایک چیلنج کی حیثیت رکھتا ہے۔

علم معدنیات (Mineralogy)

انسائیکلوپیڈیا آف بریٹانیکا میں علم معدنیات کی تعریف یوں بیان کی گئی ہے:

“Mineralogy: scientific discipline that is concerned with all aspects of minerals , including their physical properties , chemical composition, internal crystal structure , occurrence and distribution in nature , and their origins in terms of the physicochemical conditions of formation.”[3]

علم معدنیات سے مراد ایسا سائنسی علم ہے جس میں معدنیات کے بارے میں تمام پہلوؤں کا مطالعہ کیا جاتا ہے۔ اس میں معدنیات کےطبعی خواص، کیمیائی ساخت، اندرونی کرسٹل ڈھانچہ کی تشکیل وغیرہ کا احاطہ کیا جاتا ہے۔

انسائیکلوپیڈیڈک ڈکشنری آف...

اسلام اور جین مت میں طہارت کا تقابلی جائزہ

      Allah created all the required things fo the world since the world was given existence. Human was made its tenant and was equipped with art of living and eversince human life exists in all the corners of the world whatsoever religion they follow, but  they do follow a set of social principles in life. And literal meaning of those principles is called religion, because religion literally mean"way of living or manner of living". And contextually religion may be defined as the principles followed to live life.       In the light of this definition of religion some people have been confronted having no concept  of  religion, they are called Communists. But anyone who does not believe in Allah and the Prophet PBUH are termed Communists. In the following dissertation a comparison has been drawn between Islam and jeen Mat to show that no religion can compete Islam in terms of Clarity or cleanliness.

Multiple Media Information Search Framework

Nowadays, together with the increasing spread of online multimedia information, user’s information needs have become more complex. To fulfill information needs, users mainly rely on web search engines. The traditional ways of presenting search results are often unsatisfactory. Web search engines usually provide the search of multimedia documents that encapsulates different media objects. A web page is a most known example of a multimedia document. Web search approaches enable vertical search of media objects that belongs to different media formats. In vertical web search, the retrieval granules are media objects presented by employing non-blended integration mechanisms. The presentation of search results is also linear. In recent years, aggregated search approaches have emerged to satisfy user’s complex information needs. Aggregated search approaches retrieve, merge, rank, and present results to the users from separate vertical media sources. The search results are possibly integrated via blended, partial-blended, or non-blended integration mechanisms; however, the presentation is still linear. In aggregated search, the retrieved media objects have semantic and multimodal similarity relationships that are not exploited to support user’s exploration activities. Over the years, aggregated search tools have been investigated by the researchers. Aggregated search tools usually do not consider the multimodal nature of media objects in search results exploration activities. They address the exploration of only specific media types or a subset of them. Aggregated search tools enable only document-to-document browsing. Furthermore, retrieval granule are either media objects or multimedia documents. This thesis aims to address the issues that are related to the results exploration in aggregated search. The thesis focuses to provide a novel mechanism to explore results in aggregated search. The main objective is to give users a possibility to dynamically visualize and explore a search result space built over a repository of multimedia documents and their connected media objects in an integrated way. To do this a novel multiple media information search framework is proposed. Particularly, search framework initiates a search result space over the retrieved multimedia documents and their connected media objects. The search result space treats multimedia documents and media objects as retrieval granules. The search result space connects multimedia documents and media objects and media objects with each other via part-of and multimodal (textual, acoustic, and visual) similarity relationships respectively. The search result space is further exploited in results exploration activities. The search framework formally defines a set of components to provide an exploration of results in aggregated search of multiple media information. The search framework is further represented as an architecture that encapsulates framework components in data, search, data model, viii and interface layers. Data layer retrieves multimedia documents, media objects, and features associated with media objects. Search layer provides fielded search of media objects connected with the multimedia documents. Results representation layer initiates a search result space over multimedia documents and their connected media objects retrieved in aggregated search. Interface layer enables expression of multiple media based information needs and exploration of the search results. We realized the framework by implementing a full-fledged multiple media information search tool mainly to provide nonlinear interaction with the search results via full-blended integration, browsing, and visualization in an integrated way. The search tool instantiates a search result space via a particular graph data model on a publically available dataset of multimedia documents and their connected media objects. The search tool provides search results exploration by giving a results exploration mechanism and supporting various types of search tasks via particular results exploration interface components. We evaluated blended integration, browsing, and the connected search results exploration. We considered correctness and reachability factors in the effectiveness evaluation of blended integration and browsing respectively. Blended integration and browsing are compared further with the optimally ranked representation of search results, and they give satisfactory results. The effectiveness of search results exploration mechanism, search task support, and search interface components evaluated via task and scenario-based usability tests. In particular, we employed successful task completion, time-on-task, subjective measures of usability in supported search tasks, and overall user recommendations to evaluate results exploration mechanism. We tested the usability of lookup and exploratory search tasks via scenario-based evaluation. Furthermore, we conducted frequency usage, an interface component, and search results multi-representation analysis to highlight the usability of search interface components. The usability tests revealed that most users completed search task in given time constraints; search interface provides satisfactory results in subjective measures; users are satisfied with the search results exploration mechanism. The search interface supports lookup and exploratory search tasks to interact with the results. The users mostly spent time to interact with results presented via the linear list and browseable grid-based representation; however, users prefer all types of interactions given in the search interface to explore the results. Along with that, they like the browsing of multiple media information via grid and graph-based representations. Our framework provides nonlinear, multimodal, and unified exploration of results in multiple media information aggregated search in a usable way.