In the present work, steady two – dimensional laminar natural convection heat transfer of Newtonian and non-Newtonian fluids inside isosceles triangular enclosure has been analyzed numerically for a wide range of the modified Rayleigh numbers of (103 ≤ Ra ≤ 105), with non-dimensional parameter (NE) of Prandtl – Eyring model ranging from (0 to 10), and modified Prandtl number take in the range (Pr* =1,10, and 100). Two types of boundary conditions have been considered. The first, when the inclined walls are heated with different uniform temperatures and the lower wall is insulated. The second, when the bottom wall is heated by applying a uniform heat flux while the inclined walls at the constant cold temperature. Also, the non-Newtonian fluids under consideration were assumed to obey the Prandtl – Eyring model..The results are presented in terms of isotherms and streamlines to show the behavior of the fluid flow and temperature fields. In addition, some graphics are presented the relation between average Nusselt number and the various parameters. The results show the effect of non – dimensional parameter (NE) on the velocity and temperature profiles. They also show that the average Nusselt number is a strong function of modified Rayleigh number, modified Prandtl number, non-dimensional parameter, and the boundary conditions. Four different correlations have been made to show the dependence of the average Nusselt number on the non-dimensional parameter, the modified Rayleigh and Prandtl numbers.
In this research the natural frequency of a cracked simple supported beam (the crack is in many places and in different depths) is investigated analytically, experimentally and numerically by ANSYS program, and the results are compared. The beam is made of iron with dimensions of L*W*H= (0.84*0.02* 0.02m), and density = 7680kg/m3, E=200Gpa. A comparison made between analytical results from ANSYS with experimental results, where the biggest error percentage is about (7.2 %) in crack position (42 cm) and (6 mm) depth. Between Rayleigh method with experimental results the biggest error percentage is about (6.4 %) for the same crack position and depth. From the error percentages it could be concluded that the Rayleigh method gives
... Show MoreIn this paper, experimental study has been done for temperature distribution in space conditioned with Ventilation Hollow Core Slab (TermoDeck) system. The experiments were carried out on a model room with dimensions of (1m 1.2m 1m) that was built according to a suitable scale factor of (1/4). The temperature distributions was measured by 59 thermocouples fixed in several locations in the test room. Two cases were considered in this work, the first one during unoccupied period at night time (without external load) and the other at day period with external load of 800W/m2 according to solar heat gain calculations during summer season in Iraq. All results confirm the use of TermoDeck system for ventilation and cooling/heat
... Show MoreEnrollment in kindergarten child accomplishes many positive aspects, that’s what Im sure a lot of modern educational trends in child education preschool in the importance of exposing children to a variety of sensory stimuli that contribute to impart a range of sound concepts.
Current research aims to know:
1.the level of sensory perception in the first primary grade students a sample search.
2.differences in perception of elementary first-graders with variable gender male, female)) 3.differences in perception of the first primary grade students attending and not attending kindergarten in accordance with variable attendance (attending, not attending).
school students (first grade) from attendi
... Show MoreThe study area is witnessing divergence where I am North wind North East wind as we find that the north wind is getting replicated as we move from the south, The reason can be attributed to the nature of the surface of the region, with at least repeat this wind the northern region to the presence of mountain ranges, while we find that energizes the surface in the center and south helped to increase repeat this wind gusts, It also finds that the North wind East prevail in the northern region and least replicated as we move from the north to the south and to the fact that North stations are within blowing this wind sites for the circles near the display of high pressure located centers to the north-east, north and distancing itself from pa
... Show MoreThe two-dimensional transient heat conduction through a thermal insulation of temperature dependent thermal properties is investigated numerically using the FVM. It is assumed that this insulating material is initially at a uniform temperature. Then, it is suddenly subjected at its inner surface with a step change in temperature and subjected at its outer surface with a natural convection boundary condition associated with a periodic change in ambient temperature and heat flux of solar radiation. Two thermal insulation materials were selected. The fully implicit time scheme is selected to represent the time discretization. The arithmetic mean thermal conductivity is chosen to be the value of the approximated thermal conductivity at the i
... Show Moreملامح من فكرة القانون الطبيعي في حضارة العراق القديم
The insects like other creatures in the wide world, and there are more than a million class and type of these objects, some of which human haunted since the old to the present day.
In this study highlight the insect bee addressing her life and behavior, and the novelty of her and wonders what mystified by the minds of men that her world is full of mysteries and surprises drew the attention of workers in the natural history of the study and scrutiny of methods and different characteristics of scientists as she gives more than it takes. It appeared that the Islamic heritage has singled out these insects with something of interest and precise detail, but that God Almighty made suras from the Koran carrying insect name two Sura
... Show MoreThe aim of this work was to capture solar radiation and convert it into solar thermal energy by using a storage material and the heat transfer fluid like oil and water and comparison between them, we used the evacuated tube as a receiver for solar radiation, The results showed that the oil better than water as storage material and the heat transfer fluid and the effective thermal conductivity material and good for power level, rates and durations of charge and discharge cycles.
المنطق منهجا نقديا - دراسة في قراءة الشكل الجمالي كتاب (المنطق منهجا نقدياً – دراسة في قراءة الشكل الفني) يهتم الكتاب بدراسة التصورات المنطقية في الفنون التشكيلية وهو يقع في اربعة فصول خصص الاول منها لبيان المنهجية والفكرة العامة عن علاقة المعرفة بالقواعد الفكرية والقواعد المنطقية موضحا ذلك في (مدخل عام) وتعلق الفصل الثاني بالمفاهيم المنطقية وما كتبه علماء المنطق في عرض شامل ومكثف تناول فيه المؤلف مفهوم ال
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