Preferred Language
Articles
/
joe-1553
Numerical Investigation of Aerodynamic Characteristics of Supercritical RAE2822 Airfoil with Gurney Flap
...Show More Authors

Gurney flap (GF) is well-known as one of the most attractive plain flaps because of the simple configuration and effectiveness in improving the lift of the airfoil. Many studies were conducted, but the effects of GF on the various airfoil types need to be further investigated. This study aimed to clarify the effect of GF in the case of the supercritical airfoil RAE2822. This research includes a steady, two-dimensional computational investigation carried out on the supercritical airfoil type RAE-2822 to analyze Gurney flap (GF) effects on the aerodynamic characteristics of this type of airfoil utilizing the Spalart-Allmaras turbulence model within the commercial software Fluent. The airfoil with the Gurney flap was analyzed for three different height values 1%c, 2%c, and 3%c, and five mounting angles (30°,45°,60°,75°, and 90°) with the axial chord for angles of attack (-1°,-2°,-3°,0°,1°,2°,3°). The calculations showed that when GF height is increased, the maximum suction pressure on the upper surface increases by 25.4%, 36.5%, and 68.83% when the height of the Gurney flap is 1%c, 2%c, and 3%c, respectively, compared with that on the airfoil without GF. The lift coefficient was also increased, and the shock waves moved downward by increasing GF height. As Gurney flap heights increase, the drag coefficient increases gradually for positive angles of attack but for negative angles of attack. The drag coefficient also decreases with increasing the GF heights. As long as the angle of the mounting is between 45o and 90o, the lift coefficient does not differ on a large scale. For mounting angles less than 45o, the lift coefficient drops quite fast. As a result, reducing the Gurney flap’s lift enhancement and the drag coefficient increases gradually for positive angles of attack, but for negative angles, it can be noted that the drag coefficient decreases with increasing the mounting angles of GF. The calculated values of the lift and drag coefficients with an attack angle and pressure coefficient compared with the experimental values, and a good agreement was noticed. 

 

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Fri Jan 01 2021
Journal Name
Clinical Epidemiology And Global Health
Association of overweight/obesity with the severity of periodontitis using BPE code in an iraqi population
...Show More Authors

View Publication Preview PDF
Scopus (4)
Crossref (4)
Scopus Clarivate Crossref
Publication Date
Thu Jun 15 2023
Journal Name
Journal Of Baghdad College Of Dentistry
Evaluation of leukocytes cells types counts in blood from patients with different severities of periodontal diseases
...Show More Authors

Background: Periodontal diseases are inflammatory disorders caused by the accumulation of oral biofilm and the host response to this accumulation which characterized by exaggerated leukocytes and neutrophils attraction to the sites of inflammation by chemoattractants which are a very important part of the pathogenesis of periodontal diseases. This study aimed to determine and compare the clinical periodontal parameters and the leukocyte cell types in the peripheral blood between patients with gingivitis and periodontitis with different severities compared to healthy controls. Materials and methods: This study included 150 male subjects aged between 35-50 years. They were divided into three groups: gingivitis group (n=30), periodontitis p

... Show More
View Publication Preview PDF
Scopus (3)
Crossref (3)
Scopus Crossref
Publication Date
Fri Jan 10 2020
Journal Name
Polymers
Influence of Polyphosphates on the Physicochemical Properties of Poly (Vinyl Chloride) after Irradiation with Ultraviolet Light
...Show More Authors

Three new polyphosphates were synthesized in good yields by reacting diethylenetriamine with the appropriate phosphate ester in ethanol under acidic conditions. The polyphosphate structures were determined using FT-IR and 1H-NMR spectroscopies, and their elemental compositions were confirmed by EDX spectroscopy. Polyphosphates were added to poly(vinyl chloride) (PVC) at low concentrations to fabricate thin films. The PVC films were irradiated with ultraviolet light for long periods, and the effect of polyphosphates as the photostabilizer was investigated by determining changes in the infrared spectra (intensity of specific functional group peaks), reduction in molecular weight, weight loss, and surface morphology. Minimal changes we

... Show More
View Publication
Scopus (40)
Crossref (33)
Scopus Clarivate Crossref
Publication Date
Wed Aug 17 2022
Journal Name
Aip Conference Proceedings
Study of some physical and mechanical properties of paper sheets treated with different polymeric adhesive solution
...Show More Authors

The present researchers are trying to enhance the properties of paper sheet that used widely in many fields such as printing and packaging. The enhancement of paper quality is also possible to preserve paper documents of all kinds, as they are the true record, full of the history, achievements of the human being and the intellectual and cultural of the country. It is possible to improve its physical and mechanical properties and preserve them from damage through the use of some solutions of polymeric adhesives, which act as protective barriers against water and moisture penetration. The paper also has the advantage of porosity, which has been overcome by using three types of polymeric adhesives (Nitro Cellulose, Polyvinyl alcohol acetate, a

... Show More
Scopus (1)
Scopus
Publication Date
Thu Nov 17 2022
Journal Name
Journal Of Interdisciplinary Mathematics
Results of Differential Sandwich Theorem of the Univalent Functions Associated with Generalized Salageon Integro-Differential Operator
...Show More Authors

View Publication
Scopus (2)
Scopus Clarivate Crossref
Publication Date
Wed Aug 17 2022
Journal Name
Sustainability
Experimental Evaluation of the Thermoelectrical Performance of Photovoltaic-Thermal Systems with a Water-Cooled Heat Sink
...Show More Authors

A design for a photovoltaic-thermal (PVT) assembly with a water-cooled heat sink was planned, constructed, and experimentally evaluated in the climatic conditions of the southern region of Iraq during the summertime. The water-cooled heat sink was applied to thermally manage the PV cells, in order to boost the electrical output of the PVT system. A set of temperature sensors was installed to monitor the water intake, exit, and cell temperatures. The climatic parameters including the wind velocity, atmospheric pressure, and solar irradiation were also monitored on a daily basis. The effects of solar irradiation on the average PV temperature, electrical power, and overall electrical-thermal efficiency were investigated. The findings i

... Show More
View Publication
Scopus (28)
Crossref (26)
Scopus Clarivate Crossref
Publication Date
Mon Dec 06 2021
Journal Name
Karbala International Journal Of Modern Science
Calculation and comparison of certain physical properties of sample irregular galaxies with the Milky Way galaxy
...Show More Authors

View Publication
Scopus (2)
Scopus Crossref
Publication Date
Thu Dec 29 2016
Journal Name
International Journal Of English Amd Literature
THE FORMS AND FUNCTIONS OF APOLOGIES WITH INDICATIVE REFERENCES TO THE LETTERS OF KEATS AND BYRON
...Show More Authors

11-22 Description An apology may be defined as “the act of declaring one’s regret, remorse or sorrow for having insulted, failed, injured, harmed or wronged another (Internet Encyclopedia of Philosophy IEP). A definition quite interested in the function suggests that “an apology is a speech act addressed to B’s face–needs and intended to remedy an offence for which A. takes responsibility.”(Holmes, 1990: 159). Apologies are also" speech acts" that are hard to identify, define or categorize, a difficulty that arises directly out of the functions they perform (Lakoff, 2001: 201) and the forms they take. In function, they range from selfabasement for wrongdoing to the formal display of appropriate feeling. In form, they range from

... Show More
Publication Date
Sun Sep 15 2024
Journal Name
Journal Of Baghdad College Of Dentistry
Assessment of surface microhardness of enamel surface treated with Nano- HAP serum before and after bleaching
...Show More Authors

Background: Although bleaching is typically considered a safe procedure, various investigations have found minor negative effects and changes in mineral composition. The aim was to Evaluate and compare the efficacy of using Nanohydroxyapatite serum on surface microhardness of enamel surface before and after bleaching with chemically cured Boost bleaching. Material and methods: ten sound human permanent upper and lower premolar teeth were used and their roots were removed 2 mm apically to the cementoenamel junction, the crowns were sectioned mesiodistally into two halves buccal and lingual/palatal, the buccal surface was further subdivided into two halves. The samples were embeded in an acrylic resin, resulting in 30 specimens divide

... Show More
View Publication
Scopus (1)
Scopus Crossref
Publication Date
Fri Jan 01 2021
Journal Name
Journal Of Stomatology
Association of self-reported symptoms of xerostomia with vaping and cigarette smoking: a cross-sectional study
...Show More Authors

View Publication
Scopus (2)
Crossref (3)
Scopus Crossref