A numerical study of the two-dimensional steady free convection flow in an inclined annulus between two concentric square cavities filled with a porous medium is presented in this paper for the case when the side outer walls are kept with differentially heated temperature while the horizontal outer walls and the inner walls are insulated. The heated wall is assumed to have spatial sinusoidal temperature variation about a constant mean value. The Darcy model is used and the fluid is assumed to be a standard Boussinesq fluid. For the Cartesian coordinate system, the governing equations which were used in stream function form are discretized by using the finite difference method with successive under – relaxation method (SUR) and are solved by Gauss-Siedel iterative method. The upwind scheme was used for the transport terms in the energy conservation equation. The results are presented to demonstrate the streamlines, the isotherms, and the Nusselt number depending on the Rayleigh number ranging from (Ra =10 to 1000), dimension ratio from (Dr = 0.15 to 0.45), and the inclination angle from (= 0o to 45o). Also the effects of the amplitude (=0 to 1) and the wave number (f =0 to 5) of the heated side wall temperature variation on the free convection are investigated. The results show the effect of previous parameters (Ra, Dr,, , and f) on the flow fields and temperature profiles. It also show that the average Nusselt number is a strong function of the Rayleigh number, inclination angle, dimension ratio, and temperature variation. The peak value of the average Nusselt number based on the hot wall temperature is observed to occur at dimension ratio of (0.15), inclination angle of (40.1°), amplitude and wave number (1 & 0.75) for Rayleigh number of (1000).
- مشكلة البحث
تشغل مادة طرائق التدريس مكانة متميزة في عملية التعليم والتعلم لما لها من دور كبير وفاعل في إيصال المادة العلمية إلى الطالب بنجاح .
وقد عزى بعض الباحثين التأخر الذي رافق طرائق تدريس التربية الإسلامية إلى ضعف إعداد المدرسين وتأهيلهم التربوي ولا سيما أن عدد غير قليل منهم من كليات غير تربوية فهم خريجو كليات العلوم الإسلامية والجامعة الإسلامية والإدارة والاقتصاد
... Show MoreThe Dictionary of Countries by Yaqut al-Hamawi is one of the most important sources that researchers rely on in everything related to geography in knowing the names of places and countries, and the important historical information it contains about different cities and countries
this research aims it measure the technical efficiency of the branches of the General Company for Land Transport, That scattered geographically at country level, by Data Envelopment analysis (DEA) technique, as this technique relies on measuring the efficiency of a set of asymmetric Decision making units, which is one of the nonparametric mathematical methods for and application related to Linear Programming, and this is what helps the General Company for Land Transport to diagnose its branches performance by benchmarking with each other and determine the performance gap. The research found that there is variation in the level of efficiency in the company's branches
The Dictionary of Countries by Yaqut al-Hamawi is one of the most important sources that researchers rely on in everything related to geography in knowing the names of places and countries, and the important historical information it contains about different cities and countries
يهدف البحث الى التعرف على اثر استراتيجية نجمتين وامنية في تحصيل مادة الكيمياء عند طلاب الصف الثاني المتوسطولتحقيق هدف البحث تم اتباع المنهج التجريبي ذو الضبط الجزئي وتم تحديد مجتمع البحث بطلاب الصف الثاني المتوسط لجميع المدارس الثانموية والمتوسط التابعة لمديرية تربية الكرخ الثانية وتم اخنيار احد هذه المداس بصورة قصدية لتطبيق تجربة ابلبحث الحالي
هدف ال الأسلوب المعرفيّ م الإد ا ركيّ اضة للبنات، والتعرّف على علاقة التنظ ة وعلوم الر ة البدنّ ة التر لّ ة في ات المرحلة الثانّ طال إنّه احثتان اضة للبنات، وأفترضت ال ة وعلوم الر ة البدنّ ة التر ل ة في ات المرحلة الثان عض طال التأمّليّ الاندفاعيّ لدى اس الأسلوب المعرفيّ التأمّليّ الاندفاعيّ لدى عیّنة م الإد ا ركيّ ونتائج مق اس التنظ ة بین نتائج مق
... Show MoreAbu Al- Qasim Qa ,im Maqam is famous figure in political life of lranian; The life of Abu Al- Qasim Qa ,im Maqam is full of incidents and conflicts in the period of the expansion of foreign influence in lran Abu Al- Qasim Qa ,im Maqam has an important role in the history of Iran Modern political considered him one of the most prominent leaders to the unified Arabian nationalistic liberating Abu Al- Qasim Qa ,im Maqam raised in the history of the Qajar .
The study aims to introduce at the difficulties in which delay the using of the internet In the educational process – learning , Study was conducted on a sample of students in the College of Education for Girls and the effects of variables : possession of computer , availability of the internet service , and the level of parents on these difficulties , Used for this purpose, a total sample size (400) students, distributed Departments . Results showed that the most important difficulties in which delay using of internet were : Lack of knowledge of internet availability , Lack of knowledge of the aim of using this service , and the students satisfaction that the disadvantages is more than the advantages of
... Show MoreThe aim of this research is to study and test the impact of the policy of open-book accounting as one of the cost management mechanisms in achieving the competitive advantage in Jordanian industrial public companies, to achieve the objectives of the study, a field study was conducted by surveying the views of a sample of the accountants of the Jordanian industrial public companies. Hence the arithmetical Means, the Standard Deviations, the Significant Value and the Simple Linear Regression are used to test the research hypotheses and to achieve the research goals. The results of the study showed that there is a statistically significant effect of the policy of open-book accounting as one of the cost management mechanisms in achieving the
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