Natural convection in a trapezoidal enclosure with partial heating from below and symmetrical cooling from the sides has been investigated numerically. The heating is simulated by a centrally located heat source on the bottom wall, and four different values of the dimensionless heat source length, 1/5, 2/5, 3/5, 4/5 are considered. The laminar flow field is analyzed numerically by solving the steady, two-dimensional incompressible Navier-Stokes and energy equations. The Cartesian velocity components and pressure on a collocated (non-staggered) grid are used as dependent variables in the momentum equations discretized by finite volume method; body fitted coordinates are used to represent the trapezoidal enclosure, and grid generation technique based on elliptic partial differential equations is employed. SIMPLE algorithm is used to adjust the velocity field to satisfy the conservation of mass. The range of Rayleigh number is (103≤ Ra ≤105) and Prandtl number is 0.7. The results show that the average Nusselt number increases with the increases of the source length.
ﺔﻴﻋﺍﺫﻹﺍ ﺕﺎﻴﻨﻘﺘﻟﺍ ﻡﺍﺪﺨﺘﺳﺍ ﰲ ﲑﺒﻛ ﺭﻮﻄﺗ ﻦﻣ ﻝﺎﺼﺗﻻﺍ ﺮﺼﻋ ﻩﺪﻬﺷ ﻱﺬﻟﺍ ﺖﻗﻮﻟﺍ ﰲ ﺔﻴﻧﻮﻳﺰﻔﻠﺘﻟﺍﻭ ﺍ ﺢﺴﻓ ﰲ ﻢﻬﺳﺃ ﺕﺎﻄﶈﺍ ﺀﺍﻮﺳ ﺔﻴﻧﻮﻳﺰﻔﻠﺘﻟﺍ ﺕﺍﻮﻨﻘﻟﺍ ﺚﺒﻟ ﻊﺳﺍﻮﻟﺍ ﻝﺎ ( ﺔﻴﺿﺭﻷﺍ ﺔﻴﻠﺑﺎﻜﻟﺍ ﻭﺃ ﺔﻴﺋﺎﻀﻔﻟﺍ ﻭﺃ ( ﱵﻟﺍ ﺔﺻﺎﳋﺍ ﺔﻴﺋﺎﻀﻔﻟﺍ ﺕﺍﻮﻨﻘﻟﺍ ﻦﻣ ﺪﻳﺪﻌﻟﺍ ﺭﻮﻬﻇ ﰲ ﺎﻀﻳﺃ ﺪﻋﺎﺳ ﺎﳑﻭ ، ﺕﺎﻴﺋﺎﻀﻔﻟﺍ ﺭﻮﻬﻇ ﻚﻟﺫ ﻞﺒﻗ ﺩﺎﺳ ﻥﺃ ﺪﻌﺑ ﺔﻴﻣﻮﻜﺣ ﲑﻏ ﺕﺎﻴﻌﲨ ﻭ
... Show MoreThe research sought to identify the objective trends of postgraduate students at the College of Political Science - University of Baghdad for the period from 2000-2012 through the objective trends of university theses and dissertations and what are the most and least studied topics, with a re-adjustment of previously studied topics towards topics that serve issues of concern to society and avoiding topics that have been studied a lot to avoid repetition. The research came out with the following results, the most prominent of which are: The total number of what was accomplished in this college is 401 theses and dissertations, and the dissertations had the largest share of them, as their percentage reached 69%, with 275 theses compared to 126
... Show MoreThe current research seeks to identify the impact of Barman's model on acquisition of the concepts of jurisprudence of worship among students of the departments of Qur'anic sciences. To achieve the research objectives, the researcher relied on the experimental method through a design with partial control by relying on two experimental groups receiving teaching by using the Barman model and a control group receives teaching through the normal method. After applying the experiment, the study reached the following results: Students of the Department of Qur’anic Sciences in general need educational programs linked to the curriculum and built on scientific foundations, according to their needs and problems (psychological, cognitive, and soc
... Show Moreيهدف البحث الحالي التعرف على اسناتيجية هرم الافضلية في تحصيل طلاب الصف الثاني المتةسط لمادة الكيمياء ولتحقيق هدف البحث تم اتباع الننهج شبه التجريبي ذو الضبط الجزئي وتم تحديد مجتمع البحث بطلاب الصف الثاني في جميع المدارس المتوسطة والثانوية التابعة لمديرية تربية بابل قسم تربية المسيب
Abstract\
In this research we built a mathematical model of the transportation problem for data of General Company for Grain Under the environment of variable demand ,and situations of incapableness to determining the supply required quantities as a result of economic and commercial reasons, also restrict flow of grain amounts was specified to a known level by the decision makers to ensure that the stock of reserves for emergency situations that face the company from decrease, or non-arrival of the amount of grain to silos , also it took the capabilities of the tanker into consideration and the grain have been restricted to avoid shortages and lack of processing capability, Function has been adopted
... Show MoreSustainable development (SD) is an improvement that meets present needs but jeopardizes the ability of new populations to do the same. It is vital to acquaint EFL students with the terminology and idiomatic expressions of this discipline. Nowadays, sustainable development and the environment have been prioritized in every aspect of life. Since culture and the teaching of Foreign language English cannot be separated, the English language becomes the mean of communication in health, economics, education, and politics. Thus, integrating sustainable development goals within language learning and teaching is very important. This descriptive quantitative study aims to investigate the perception of EFL pre-service teachers of sustainable develo
... Show Moreتناولنا في بحثنا أحد اساليب البرمجة الخطية وهي الطريقة المبسطة لتقدير معلمات انموذج الانحدار الخطي عن طريق اختيار دالة الهدف التي تعمل على تقليل الحد الادنى لمجموع الاخطاء الناتجة من تقدير المعلمات بطريقة المربعات الصغرى الاعتيادية ( OLS) حيث سيتم في الطريقة المبسطة ( simplex) فرض قيود على نفس الاخطاء نفسها بهدف تصغيرها الى اقل ما يمكن للحصول على تقديرات افضل لمعلمات انموذج الانحدار الخطي . على اساس ان طريقة المرب
... Show MoreThis research deals with study and analyze the industrial buyer behavior and identified its objectives by determine the nature of selection the members of the purchases committees and determine the role of the purchases committees to provide requirements of the educational and scientific process and knowledge Impact of the factors ( environmental , organizational , social , and individual ) and positions of the purchase in the behavior of the members of the purchases committees and starts the importance of research in it helps university administrations in the correct choice for the members of the purchases committees and gives a picture of professional conduct professional who is supposed to b
... Show MoreAbstract:
This research aims to know the reflection of selection of employees strategy dimensions ( selection of employees strategy standards, procedures selection of employees strategy , efficiency based on a selection of employees strategy) on human capital (knowledge, skills, abilities) in a sample of Lecturers consists of (Deans and assistants and heads of departments) in ( Baghdad University) included nine colleges and university president as total sample size (54), which represent almost 50% of the total research community of 116, was used in the light of the objectives of the research descriptive and analytical approach, has been a resolution main tool for data collection as well as the interview p
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