Preferred Language
Articles
/
WBj_aZQBVTCNdQwCgRVc
The Convective Instability of BEK Family of Non-Newtonian Rotating Boundary-Layer Flows
...Show More Authors

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.

View Publication Preview PDF
Quick Preview PDF
Publication Date
Sun Jun 01 2014
Journal Name
مجلة كلية مدينة العلم الجامعة
Palynological study for nine cultivated species of Asteraceae family
...Show More Authors

The current research included palynological study for nine ornamental cultivated species of Asteraceae family. The study included measurement the dimensions of pollen grains and there shape in polar view and equatorial view, sculpturing,colpi length and width, spines length and number of spines rows between colpiand exine thickness, the study showed variations in pollen grains characters forthe studied taxa

Publication Date
Mon Apr 01 2019
Journal Name
Journal Of Engineering
Effect of Thickness Variable on the Bending Analysis of Rotating Functionally polymer Graded Carbon Nanotube Reinforced Cylindrical Panels
...Show More Authors

This study offers the elastic response of the variable thickness functionally graded (FG) by single walled carbon nanotubes reinforced composite (CNTRC) moderately thick cylindrical panels under rotating and transverse mechanical loadings. It’s considered that, three kinds of distributions of carbon nanotubes which are uniaxial aligned in the longitudinal direction and two functionally graded in the transverse direction of the cylindrical panels. Depending on first order shear deformation theory (FSDT), the governing equations can be derived. The partial differential equations are solved by utilizing the technique of finite element method (FEM) with a program has been built by using FORTRAN 95. The results are calculat

... Show More
View Publication Preview PDF
Crossref (4)
Crossref
Publication Date
Fri Jan 01 2021
Journal Name
Fme Transactions
Unsteady nonlinear panel method with mixed boundary conditions
...Show More Authors

A new panel method had been developed to account for unsteady nonlinear subsonic flow. Two boundary conditions were used to solve the potential flow about complex configurations of airplanes. Dirichlet boundary condition and Neumann formulation are frequently applied to the configurations that have thick and thin surfaces respectively. Mixed boundary conditions were used in the present work to simulate the connection between thick fuselage and thin wing surfaces. The matrix of linear equations was solved every time step in a marching technique with Kelvin's theorem for the unsteady wake modeling. To make the method closer to the experimental data, a Nonlinear stripe theory which is based on a two-dimensional viscous-inviscid interac

... Show More
View Publication
Scopus (2)
Crossref (2)
Scopus Clarivate Crossref
Publication Date
Tue Dec 01 2020
Journal Name
2020 5th Ieee International Conference On Recent Advances And Innovations In Engineering (icraie)
The New Way of Estimating the PCB's Lifetime of Fatigue using the Principle of Linear Accumulated Damage in Various Boundary Condition
...Show More Authors

View Publication
Scopus Clarivate Crossref
Publication Date
Sat Feb 09 2019
Journal Name
Journal Of The College Of Education For Women
Emotional Reassurance and its relationship with family climate at the students of kindergarten Department
...Show More Authors

The research aims to identify the level of emotional reassurance and level of family climate at
the students of kindergarten Department.
Search tool :
The two researchers built a measure of emotional reassurance and consisting of (26) items and
the scale of family climate consisting of (30 ) items .
The applied Statistical methods:
The two researchers used the statistical bag spss and they used t-test and Pearson correlation
coefficient and analysis of variance and Alpha -Cronbach .
The results showed : The students of kindergarten Department have a high level of
emotional reassurance and good family climate and there is a relationship between emotional
reassurance and family climate .
The two researchers

... Show More
View Publication Preview PDF
Publication Date
Thu Nov 28 2024
Journal Name
Journal Of Emergency Medicine, Trauma And Acute Care
Assessment of practices and attitudes of undergraduate students toward family violence in the University of Baghdad
...Show More Authors

Objectives: The aim of this study was to assess undergraduate student's practices and attitudes toward family violence in the University of Baghdad.

Methods: This was a descriptive study on non-probability (purposive) sample of 100 undergraduate students from different colleges at the University of Baghdad from November 15, 2022 to May 20, 2023. A validated questionnaire was prepared with 43 questions, which consisted of three parts: eight items related to students’ demographic data, 13 items related to students’ attitudes, and 22 items related to students’ practices.

... Show More
View Publication
Scopus (4)
Crossref (2)
Scopus Crossref
Publication Date
Wed Feb 20 2019
Journal Name
Iraqi Journal Of Physics
The influence of CdCl2 layer and annealing process on the structural and electrical properties of CdTe films
...Show More Authors

A polycrystalline CdTefilms have been prepared by thermal evaporation technique on glass substrate at room temperature. The films thickness was about700±50 nm. Some of these films were annealed at 573 K for different duration times (60, 120 and 180 minutes), and other CdTe films followed by a layer of CdCl2 which has been deposited on them, and then the prepared CdTe films with CdCl2 layer have been annealed for the same conditions. The structures of CdTe films without and with CdCl2 layer have been investigated by X-ray diffraction. The as prepared and annealed films without and with CdCl2 layer were polycrystalline structure with preferred orientation at (111) plane. The better structural pr

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Sat Sep 01 2007
Journal Name
Al-khwarizmi Engineering Journal
Free Convective Heat Transfer with Different Sections Lengths Placed at the Exit of a Vertical Circular Tube subjected to a Constant Heat Flux
...Show More Authors

A free convective heat transfer from the inside surface of a uniformly heated vertical circular tube has been experimentally investigated under a constant wall heat flux boundary condition for laminar air flow in the ranges of RaL from 6.9108 to 5109. The effect of the different sections (restrictions) lengths placed at the exit of the heated tube on the surface temperature distribution, the local and average heat transfer coefficients were examined. The experimental apparatus consists of aluminum circular tube with 900 mm length and 30 mm inside diameter (L/D=30). The exit sections (restrictions) were included circular tubes having the same inside diameter as the heated tube but with different lengths of

... Show More
View Publication Preview PDF
Publication Date
Thu Nov 01 2018
Journal Name
Computers & Fluids
Assessing moment-based boundary conditions for the lattice Boltzmann equation: A study of dipole-wall collisions
...Show More Authors

View Publication
Scopus (20)
Crossref (19)
Scopus Clarivate Crossref
Publication Date
Thu May 06 2010
Journal Name
Dirasat, Pure Sciences
A Study of the Effects of the Solar Cycle 22, on the Critical Frequencies of F1 Layer over Baghdad
...Show More Authors

This paper aims to study the effects of the long term solar activity on the critical frequencies of ionospheric F1 layer over Baghdad city, during the solar cycle 22, within (1988- 1995). It is found that the critical frequency of this layer is closely related to the sunspots number during the years of the solar cycle 22, at a middle latitude region of the world. The study discussed the effect of sunspot numbers and solar events on the electron densities of F1 layer, which is the most important ionospheric parameter.