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).
The calamities, calamities, problems and constant dilemmas that society is experiencing have made it the responsibility of professors and researchers to find appropriate and effective solutions to these issues, and among those calamities that our societies faced was the problem of the epidemic represented by (Corona-Covid-19),
بدأت الشركات تخطو خطوات متسارعة باستخدام أنظمة تكنولوجيا المعلومات في عملياتها المالية وباعتماد قليل على الورق والذي يتم الاحتفاظ بالنسخ الأصلية منه تعزيزا للإجراءات التي تمت معالجتها الكترونيا. إن ممارسة الشركات وبشكل متزايد الأسلوب الواقعي (Virtualization) في علاقاتها مع الموردين والمستهلكين والشركاء أدى للحاجة المتزايدة للثقة والتأكيد على مثل هذه العلاقات مما يولد ضغطا كبيرا ع
... Show More
المؤلف / د. محمود أحمد شاكر غضيب تدريسي في جامعة بغداد / كلية العلوم الإسلامية / قسم اللغة العربية / حاصل على شهادة الدكتوراه عام 2019 في الادب العربي الإسلامي
Graph is a tool that can be used to simplify and solve network problems. Domination is a typical network problem that graph theory is well suited for. A subset of nodes in any network is called dominating if every node is contained in this subset, or is connected to a node in it via an edge. Because of the importance of domination in different areas, variant types of domination have been introduced according to the purpose they are used for. In this paper, two domination parameters the first is the restrained and the second is secure domination have been chosn. The secure domination, and some types of restrained domination in one type of trees is called complete ary tree are determined.
(19)
(2)
كَشفت التنقيبات في مدن العراق القديم كالوركاء وماري عـن بقايا أبنية المدارس الموسيقية ( ) . وفي العصر السومري الحديث ( 2000 – 1950 ق. م. ) حُفِظ ما يؤيد وجود مواد المنهج الموسيقي النظري والعملي لعملية التعليم في مدرسة المعبد أو القصر الملكي ، إضافة لبعض اللقى الآثارية كآلات فخارية خاصة بالطفل ، والتي بوساطتها كان يتم تعليم الطفل في البيت ( ) . واحتلت الموسيقى مكانة هامة في حضارات الشرق المختلفة المُتزامنة مع حضارات و
... Show MoreLanguage is a gift from God to His servants, as it is a tool of communication, rather it is a tool of life, and without it, life cannot be straight and complete.
A language is a kind of substitution. A vocal disorder that may be a disease of speech, and it is one of the obstacles caused by organic and congenital causes, perhaps the common one is genetic.If we separate between lisping in children and separating it from what happens in adults, we find that lisping in children may have psychological causes as well as other ones, this is what we will show in this research.
قياس جودة نظام الحكم أنموذج فعالة الأداء الحكومي في العراق
(1)
Libraries were and still are the source of science and knowledge in schools, universities and science houses. Therefore, it is a must to briefly display Libraries’
