The BEK family of flows have many important practical applications such as centrifugal pumps, steam turbines, turbo-machinery and rotor-stator devices. The Bödewadt, Ekman and von Kármán flows are particular cases within this family. The convective instability of the BEK family of rotating boundary-layer flows has been considered for generalised Newtonian fluids, power-law and Carreau fluids. A linear stability analysis is conducted using a Chebyshev collocation method in order to investigate the effect of shear-thinning and shear-thickening fluids for generalised Newtonian fluids on the convective Type I (inviscid crossflow) and Type II (viscous streamline curvature) modes of instability. The results reveal that shear-thinning power-law fluids have a universal stabilising effect across the entire BEK family of flows. However, the convective instability characteristics for the shear-thinning and shear-thickening Carreau fluids are affected by the value of the relaxation parameter k. The results reveal that Shear-thinning Carreau fluids have a small destabilising effect, while shear -thickening fluids have a slight stabilising effect on the Type I and Type II mode for the BEK family of flows when k =100. On the other hand, shear-thinning and shear-thickening Carreau fluids are found to have stabilising and destabilising effect, respectively for optimal relaxation value ko. The results are presented in terms of neutral curves and growth rates. Furthermore, an energy analysis is presented to gain insight into the underlying physical mechanisms behind the stabilising effects of generalized Newtonian fluids. In conclusion, the use of shear-thinning power-law and Carreau fluids with optimal value ko can be recommended to reduce skin-friction drag in enclosed rotor-stator devices for the entire BEK family of flows.
Abstract
It considers training programs is an important process contributing to provide employees with the skills required to do their jobs efficiently and effectively, so it should be concerned with and the focus of all government our organizations, and perhaps the most important reasons that I was invited to select the subject (evaluation of training programs directed toward the diagnosis of the phenomenon of financial and administrative corruption) It is the importance of those programs working in the regulatory institutions General and the Office of Inspector General of Finance and the Ministry particularly for employees because of their role in the development of their skills and their experience and their beha
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The present study aims to identifying the effect of Eurygaster integriceps infection on the quality features of the local wheat varity IBA 99. The result revealed significant decrease in the percentage of protein of infected wheat at (4, 5)% compared to sound wheat values for the sound wheat were (10.9%) whereas those for the infected wheat were(9.0, 8.4 )% also the result revealed significant increased in the percentage of ash in the infected wheat flour. The result showed significant decrease in the percentage of wet and dry gluten in the infected wheat by sun bug at the rate of (2, 3, 4, 5)% compared to sound wheat value (27, 9% and 25, 23, 22, 22, 20%) for wet gluten and (8.2, 7.8, 7, 7.2, 6%) for dry glutin . The value of sedimentati
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The construction of development is required to develop various economic sectors with the necessity to meet the various requirement of both individuals and institutions , or through the import process , which must be commensurate with the needs of the market and the economy and development. But in fact , we found that the process of import in Iraq after 2003 took a turn dangerous excesses on limits of philosophy and objectives of the import , which reflected the level of national production as well as the policy of dumping and given to the lack of matching a lot of goods and materials imported for Standards and Measures of quality and stands behind it causes many of them exposure to the market and weak sectors with an o
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Recent developments in two main phases of cumulus cloud studies are discussed; first the relations between the clouds and their energy sources in the subcloud layer and second, the interaction between the clouds and their environment in the cloud layer. Under the first heading, the various originating impulses for cumulus formation are mentionitd. and how the character of this impulse affects the spacing, scale and temperature structure of the clouds. The possible origins of trade cumuli are considered.
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Make a search on the vegetative parts of the plant local horse guilt of some elements in the Haj Omran area in northern Iraq has included recognition of certain nutrients
The parasite E.histolytica was first isolated from a stool sample, and then cultivated and maintained in vitro using Locke-egg medium (LEM) and Liver infusion agar medium (LIAM) . Then, the effect of some types of erythrocytes (human and sheep), on the growth and activity of the parasite in the two culture media was investigated. The parasite was able to ingest and lysis erythrocytes of human and sheep that were supplemented to the culture media and such manipulation was able to augment the reproduction rate of the cultivated E. histolytica, however, such consequence was media- and concentration-dependent. The reproduction rate was significantly increased (66.0, 57.5 and 58.6%, respectively) in LEM medium containing human erythrocytes ty
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The present paper applies Fanon Psychological reading of the problem of the Black introduced in his book Black Skin White Mask to Crooks, The black Character in John Steinbeck’s Of Mice and Men. The analysis of this character infers three essential points regarding the artistic achievement of the author. First, he uses a fictional character that offers a psychological interpretation of the black problem of alienation and loneliness in a way that does not disgrace the black. Second, he applies Fanon’s way of showing the various attitudes that the black adopts in contact with the white society. Third, he affirms that the black inferiority complex comes as a result of double proc
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