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Home > Flow and Heat Transfer Analysis for Arbitrary and Hyperbolic Stretching Surfaces

Flow and Heat Transfer Analysis for Arbitrary and Hyperbolic Stretching Surfaces

Thesis Info

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Author

Adeel Ahmad

Program

PhD

Institute

COMSATS University Islamabad

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2012

Thesis Completion Status

Completed

Subject

Mathemaics

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/503

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726217972

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The main purpose of this thesis is to discuss the fluid flow driven by stretching of the sheet. In fluid dynamics, there are many mechanisms to drive the fluid flow: like the motion of the boundaries, the pressure gradient and the buoyancy force. Of these mechanisms, the motion of the boundaries remains the most important. And among many fluid flows driven by the motion of the boundaries, the flow induced by stretching of the surface has been of greatest value and importance. In fact its importance lies in the application of stretching sheets in industry and engineering. Such flows are generally generated in extrusion of polymers, fibers spinning, hot rolling, manufacturing of plastic and rubber sheet, continuous casting and glass blowing. The stretching of the sheets have been initially undertaken in Newtonian fluid and later on extended to non-Newtonian fluids-- because of their application in polymer industry. The heat transfer through a fluid in the presence of fluid flow is also a subject of immense importance both for understanding of fluid flow and its applications in vast areas of industrial problems. Keeping in view the importance of the flow and heat transfer by stretching sheet a huge amount of work has been published for linear, power law and exponential stretching of the sheets in Newtonian and non-Newtonian fluids. However, the bulk of this work describes the flow and heat transfer past a continuous stretching surface taking linear, polynomial, power law and exponential stretching velocities and temperature distributions. However, this has always been a challenge for the scientists and engineers to introduce new stretching velocities for the solutions of non-linear equations on the one hand and its industrial applications on the other hand. The present thesis extends the class of stretching problems by introducing a hyperbolic stretching velocity and temperature distribution on the sheet, for the first time. The appropriate similarity transformations are introduced to reduce PDEs into ODEs. Arbitrary stretching and non- Newtonian fluids are also taken into consideration. These investigations will go a step forward in understanding the fluid flow and heat transfer for so far unaccounted stretching of the sheet and its possible industrial applications both in Newtonian and non- Newtonian fluids. The first chapter of this thesis contains the history and literature related to stretching sheet problems and states the basic definitions and equations to be used in later chapters. In second chapter we introduce the concept of hyperbolic stretching of the sheet for the first time in this thesis. The boundary layer flow and heat transfer analysis of an incompressible viscous ixfluid for a hyperbolically stretching sheet is investigated. The analytical and numerical results are obtained using series expansion method and Local Non-Similarity (LNS) methods respectively. Analytical and numerical results for skin friction and Nusselt number are calculated and compared with each other. The significant observation is that the momentum and thermal boundary layer thicknesses decrease as the distance from the leading edge increases. The well- known solution of linear stretching is found as the leading order solution for the hyperbolic stretching. The contents of this chapter have been published in Applied Mathematics and Mechanics (English Edition), 33(4), 445–454 (2012). Flow and heat transfer of an electrically conducting viscous fluid over a hyperbolic stretching sheet with viscous dissipation and internal heat generation is investigated in third chapter. The suitable transformations reduce the governing equations in a tractable form for the analytical and numerical solutions. The same analytical and numerical methods, as in chapter two, are used to obtain the results. The essence of this paper is to examine the effects of viscous dissipation, magnetic field and heat generation in a recent paper of hyperbolic stretching sheet presented in last chapter. This work has been submitted in International Journal of Numerical Methods for Heat and Fluid Flow for publication. Fourth chapter deals with the study of mixed convection flow and heat transfer of a viscous fluid along a vertical hyperbolic stretching wall. The results have been obtained considering the effect of heat generation/absorption. The solutions for forced convection flow over a linear stretching surface with linear temperature distribution in the presence of heat source/sink are found to be the leading order solutions of mixed convection past a hyperbolic stretching wall. In next chapter, the boundary layer flow and heat transfer analysis of an incompressible nanofluid for a hyperbolically stretching sheet is presented. The model used considers the effects of Brownian diffusion and the thermophoresis. Analytical and numerical results for skin friction, Nusselt number and Sharwood number are calculated and compared with each other. The effects of different physical parameter on velocity, temperature and concentration of nanoparticles are also analyzed. The leading order solution of this problem represents the flow, heat and mass transfer of an incompressible viscous fluid over a linearly stretching surface. The boundary layer flow of second grade fluid over a permeable stretching surface with arbitrary velocity and appropriate wall transpiration is investigated in fifth chapter. The fluid is electrically conducting in the presence of constant applied magnetic field. Exact solution to the nonlinear xflow problem is presented. The contents of this chapter are published in Applied Mathematical Letters, 24 (2011), 1905–1909. The last chapter presents an exact analytical solution of magneto hydrodynamic (MHD) viscous flow over a permeable sheet with partial slip boundary conditions. The flow is induced by an arbitrary stretching of the surface. The exact analytical solution of the problem becomes possible by taking an appropriate wall transpiration velocity. An existing solution for flow generated by arbitrary stretching surface with no slip condition class of the exact solutions of the Navier Stokes equations for stretching surface.
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آرزوؔ لکھنوی

آرزوؔ لکھنوی
جناب آرزوؔ جلال لکھنوی کے جانشین اور اردو زبان و ادب کے ماہر و محقق تھے اس پر ان کی نگاہ بڑی وسیع تھی، انہوں نے اردو شاعری میں زبان کی سادگی و سہولت یا موجودہ اصطلاح میں ہندوستانیت کا نیا نمونہ قائم کیا، وہ حتی الامکان عربی اور فارسی کے مشکل الفاظ اور ترکیبوں سے پرہیز اور خالص ہندوستانی الفاظ استعمال کرتے تھے، جن شعراء نے ان کی تقلید کی کوشش کی وہ کامیاب نہ ہوسکے اور ان کی شاعری یا ہندی کوتاہ بن گئی یا بے رنگ و بے مزہ ہوگئی، آرزو کی یہ خصوصیت تھی کہ انہوں نے زبان کی ہندوستانیت کے ساتھ اردو شاعری کا آب ورنگ اور اس کی دلآویزی قائم رکھی، جو زبان پر ان کی غیر معمولی قدرت کا ثبوت ہے، انہوں نے اپنے کلام کے کئی مجموعے فغانِ آرزو، جہان آرزو، اور سریلی بانسری یادگار چھوڑے ہیں، ان دونوں اساتذہ کے بعد لکھنو پرانی یادگار سے خالی ہوگیا، بلکہ ان پر اس دورہی کا خاتمہ ہوگیا ، اﷲ تعالیٰ ان کی مغفرت فرمائے۔
(شاہ معین الدین ندوی، مئی ۱۹۵۱ء)

 

کارڈز میں کفالہ کی شرعی و فقہی حیثیت اور عصرِ حاضر کے مالیاتی اداروں میں اس کا عملی تطبیق

Cards are the plastic money of current era, and Kafala by means of their warranty is little much we know about. In this article we will discuss the necessity, use and framework of Kafala for the Debit & Credit cards issued by banks and financial institutes, in the light of Qur’an and Sunnah, Ijma-e-Umma and religious researchers.

Role of Halocarbons and Polychlorinated Biphenyls in the Development of Hepatitis

The present work is concerned with the determination of blood parameters, enzyme levels, blood chemistry and pesticide residues in the blood samples from different areas of Karachi in comparison with unexposed persons (i.e., control). Total 45 persons (exposed to pesticides) were taken in this study to assay the pesticides residues in their blood and also observed the morphological and chemical changes in the blood of affected persons. From 45 persons, only 20 persons were found positive and included in the study. Out of ten (10) standard pesticides five differentpesticides were identified in the blood of exposed persons such as cypermethrin, deltamethrin, polytrin-C, malathion and permethrin. The other standard pesticides such as DDE, DDT, match, diazinon and monocrotophos were not detected. In addition blood samples were also collected from ten (10) normal persons (not exposed to pesticides) for the determination of blood parameters, enzymes levels and blood chemistry. Regarding blood parameters approximately all the blood samples had significant variations i.e., (increase or decrease level) possibly due to the cumulative effect of pesticide residues e.g., Majid a young male aged 25 years had been exposed to pesticides for long time and therefore his TLC and platelet counts were found high in addition to low levels of RBC count, Hb, Hct and MCH which probably due to the excessive secretion of enzymes. Similarly, Ghulam Hussain another young male person aged only 08 years had low levels of RBC, Hb, Hct, platelet, MCV and MCH, which may be due to toxic effects of pesticides. In differential leukocyte count (DLC), granulocyte count was found in lower limits in 40 samples and showed normal limits in 05 samples. Lymphocyte count was xi found high in 31 samples. Low limit of lymphocyte was not found in any person. Similarly, monocyte count was found in high limits in 38 samples. Low monocyte count was not noted in any sample and the rest of the samples had normal limits of monocyte. Positive effects of pesticide residues were also observed on the enzyme levels. Regarding enzyme levels GPT, ALP, and ɣ - GT had higher levels in maximum number of samples. Cholinesterase was found high in 6 samples out of 45 samples and the highest was found in case of Farhan and Abdul Rahmanwhere as low limit of cholinesterase was noted in 15 samples out of total samples which may due to prolonged exposure of pesticides. GPT was found in high limits in all the samples. Also ɣ - GT and ALP found high in all the samples. Effect of pesticide residues were also observed on the blood chemistry. Regarding total bilirubin only one sample showed normal limit. The rest of the samples had raised total bilirubin and the highest was found in Javed a young male person aged 12 years. Similarly, in case of bilirubin direct all the blood samples showed increased level. The standard chromatograms of 10 different pesticides such as match, cypermethrin, deltamethrin, polytrin-C, diazinon, DDE, monocrotophos, DDT, malathion and permethrin were prepared on HPLC and their retention time (RT) was noted. Calculation was done for the quantity of pesticides residues from the peaks of chromatograms. Regarding pesticide residues, out of total 45 samples, only 20 persons were found positive for residues. The quantity of pesticide was determined by comparing xii the peak area of the standard pesticide with the sample peaks. After analysis, it was found that out of 20 samples deltamethrin and cypermethrin were found in noticeable amount in 6 samples. Also polytrin-C, malathion and permethrin were found in 2, 1 and 5 samples respectively. The pesticides such as match, diazinon, DDT and monocrotophoswere not detected in any sample.