Preferred Language
Articles
/
joe-2040
Numerical Simulation of 3D- Flow Structure and Heat Transfer for Longitudinal Riblet Upstream of Leading Edge Endwall Junction of Nozzle Guide Vane
...Show More Authors

The simulation have been made for  3D flow structure and heat  transfer with and without

longitudinal riblet upstream of leading edge vane endwall junction of first stage nozzle guide vane .The research explores concept of weakening the secondary flows and reducing their harmful effects.Numerical investigation involved examination of the secondary flows ,velocity and heat transfer rates by solving the governing equations (continuity, Navier -stokes and energy equations ) using the known package FLUENT version (12.1).The governing equations were solved for three dimentional, turbulent flowe, incompressible with an appropriate turbulent model (k-ω,SST) .The numerical solution was carried out for 25 models of V-groove riblet with wide ranges of height (h) and space (s). The results indicated that, the riblet endwall junction was a powerful tool for controlling the flow structure, reducing secondary flow formation,and elimination the effect of heat transfer at leading edg and passage . The drag reduction produced by riblet was proportional with their height and space. V-groove riblet with dimension of (h=1.35mm and s=2.26mm) was found to be the most effective in reduction of drag (2.7%) and heat transfer (21%) so it was selected as an optimum dimension of riblet model. The results also showed that the drag reduction produced by riblet was proportional to their size. The riblet model had a great effect in elimination spanwise ,pitchwise velocities ,but strength the streamwise velocity .At leading edge ,the effect of secondary flow was extended up to 23% from span height and 35% upstream leading edge .The riblet model caused an increase in momentom at a region very close to leading edge and to move stagnation point very close to the leading edge.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Mon Sep 01 2008
Journal Name
Al-khwarizmi Engineering Journal
Design and Simulation of GaussianFSK Transmitter in UHF Band Using Direct Modulation of ΣΔ Modulator Fractional-N Synthesizer
...Show More Authors

This research involves design and simulation of GaussianFSK transmitter in UHF band using direct modulation of ΣΔ  fractional-N synthesizer with the following specifications:

Frequency range (869.9– 900.4) MHz, data rate 150kbps, channel spacing (500 kHz), Switching time 1 µs, & phase noise @10 kHz = -85dBc.

New circuit techniques have been sought to allow increased integration of radio transmitters and receivers, along with new radio architectures that take advantage of such techniques. Characteristics such as low power operation, small size, and low cost have become the dominant design criteria by which these systems are judged.

A direct modulation by ΣΔ  fractional-N synthesizer is proposed

... Show More
View Publication Preview PDF
Publication Date
Thu Feb 01 2024
Journal Name
Journal Of Engineering
Assessment of Bearing Capacity and Settlement Characteristics of Organic Soil Reinforced by Dune Sand and Sodium Silicate Columns: A Numerical Study
...Show More Authors

Organic soil is problematic soils in geotechnical engineering due to its properties, as it is characterized by high compressibility and low bearing capacity. Therefore, several geotechnical techniques tried to stabilize and improve this soil type. In this study, sodium silicate was used to stabilize sand dune columns. The best sodium silicate concentration (9%) was used, and the stabilized sand dune columns were cured for seven days. The results for this soil were extracted using a numerical analysis program (Plaxis 3D, 2020).In the case of studying the effect of (L/D) (where ‘’L” and ‘’D’’ length and diameter of sand dune columns) of a single column of sand dunes stabilized with sodium silicate with a diff

... Show More
View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Thu Mar 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
The Impact of Intellectual trends on the nature of the Economic Structure of Iraq
...Show More Authors

The Impact of Intellectual trends on the nature of the Economic Structure of Iraq

View Publication Preview PDF
Crossref
Publication Date
Tue Jun 01 2021
Journal Name
Caspian Journal Of Environmental Sciences
Numerical response of predator chrysoperla mutata maclachlan to varying densities of lipaphis erysimi (Kalt.)
...Show More Authors

Scopus (2)
Scopus
Publication Date
Sat Jan 07 2023
Journal Name
Transportation Infrastructure Geotechnology
Numerical Study of the Seismic Response of Closed-Ended Pipe Pile in Cohesionless Soils
...Show More Authors

Scopus (14)
Crossref (9)
Scopus Clarivate Crossref
Publication Date
Fri Nov 12 2021
Journal Name
Transportation Infrastructure Geotechnology
Numerical Modeling of Pullout Capacity of Screw Piles Under Seismic Loading in Layered Soil
...Show More Authors

View Publication
Scopus (6)
Crossref (7)
Scopus Clarivate Crossref
Publication Date
Thu Mar 31 2016
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Permeability Prediction in One of Iraqi Carbonate Reservoir Using Hydraulic Flow Units and Neural Networks
...Show More Authors

Permeability determination in Carbonate reservoir is a complex problem, due to their capability to be tight and heterogeneous, also core samples are usually only available for few wells therefore predicting permeability with low cost and reliable accuracy is an important issue, for this reason permeability predictive models become very desirable.

   This paper will try to develop the permeability predictive model for one of  Iraqi carbonate reservoir from core and well log data using the principle of Hydraulic Flow Units (HFUs). HFU is a function of Flow Zone Indicator (FZI) which is a good parameter to determine (HFUs).

   Histogram analysis, probability analysis and Log-Log plot of Reservoir Qua

... Show More
View Publication Preview PDF
Publication Date
Wed Jan 04 2023
Journal Name
Frontiers In Chemestry
Thermal and flow performance analysis of a concentrated linear Fresnel solar collector with transverse ribs
...Show More Authors

This article deals with the impact of including transverse ribs within the absorber tube of the concentrated linear Fresnel collector (CLFRC) system with a secondary compound parabolic collector (CPC) on thermal and flow performance coefficients. The enhancement rates of heat transfer due to varying governing parameters were compared and analyzed parametrically at Reynolds numbers in the range 5,000–13,000, employing water as the heat transfer fluid. Simulations were performed to solve the governing equations using the finite volume method (FVM) under various boundary conditions. For all Reynolds numbers, the average Nusselt number in the circular tube in the CLFRC system with ribs was found to be larger than that of the plain abs

... Show More
Scopus (7)
Crossref (7)
Scopus Clarivate Crossref
Publication Date
Sun Mar 01 2020
Journal Name
Baghdad Science Journal
The Influence of Magnetohydrodynamic Flow and Slip Condition on Generalized Burgers’ Fluid with Fractional Derivative
...Show More Authors

This paper investigates the effect of magnetohydrodynamic (MHD) of an incompressible generalized burgers’ fluid including a gradient constant pressure and an exponentially accelerate plate where no slip hypothesis between the burgers’ fluid and an exponential plate is no longer valid. The constitutive relationship can establish of the fluid model process by fractional calculus, by using Laplace and Finite Fourier sine transforms. We obtain a solution for shear stress and velocity distribution. Furthermore, 3D figures are drawn to exhibit the effect of magneto hydrodynamic and different parameters for the velocity distribution.

View Publication Preview PDF
Scopus (3)
Crossref (1)
Scopus Clarivate Crossref
Publication Date
Sun Mar 15 2020
Journal Name
Journal Of Baghdad College Of Dentistry
The impact of dental environment stress on caries experience, salivary flow rate and uric acid
...Show More Authors

Background: Several pathologies of the oral cavity have been associated with stress. Dental students need to gain assorted proficiencies as theoretical knowledge, clinical proficiencies, and interpersonal dexterity which is accompanied with high level of stress. Uric acid is the major antioxidant in saliva. The aim of this study is to assess the dental caries experience among dental students with different levels of dental environment stress in relation to physicochemical characteristics of whole unstimulated saliva.

Materials and Methods: the total sample is composed of 300 dental students (73 males, 227 female) aged 22-23 years old, from collage of dentistry / university of Baghdad, from the 4t

... Show More
View Publication Preview PDF
Scopus (7)
Crossref (2)
Scopus Crossref