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البحوث العلمية

2020

Experimental and FEM analysis investigation of various processing routes of the planar twist channel angular extrusion process

2020-05
International Journal of Mechanical and Production Engineering Research and Development (القضية : 3) (الحجم : 10)
Severe Plastic Deformation (SPD) is the most appropriate top-down method for making nanocrystalline or ultrafine grained metal structures. Achieving a good distribution and higher values of equivalent plastic strain in one pass is the main parameter in severe plastic deformation processes. To solve this challenge, integrating different SPD processes is required. The planartwist channel angular extrusion process is one of the recently proposed methods of SPD as a rearrangement of two Simple Shear Extrusion (SSE) and Equal Channel Angular Pressing (ECAP) processes. In this study, Finite Element (FE) simulation of the variousroutes in the 2ndcycle of this method is done. Then, the micro hardness test of the processed samples was performed. Finite element analysis results illustrate that the C1, C2,A1, and B2 routes have the most uniform distribution of equivalent plastic strain in the cross section area of the specimen, and B2 and A1 paths have more equivalent plastic strain values. The highest non-uniform distribution of the equivalent plastic strain is illustrated in the paths B1 and D2. The results of the micro hardness test validated FEM results. Therefore, the best options for the second cycle of the PTCAE method are the paths A1 and B2.

Numerical Simulation of the Formation of Vortices Around Rigid Cylinders as a Issue of Fluid-Structure Interaction Using Immersed Interface Method

2020-02
Mechanics (القضية : 1) (الحجم : 26)
The numerical simulation of the flow of fluid through one or a set of objects that causes the flow to separate from the surface of them has been the subject of interest by researchers over the past few decades. One of the most important types of these objects is those with a square cross section which have important and diverse applications in different industries. One of the practical applications of these types of streams is flow around chimneys, high-rise buildings, naval structures, suspended bridges, airplane wings, ship propellers and ducts. In this research, the immersed interface method is used which is a non-conforming method to the boundary. Eulerian mesh for fluid field, and Lagrangian mesh for solid field is used. The connection of these two networks is established by the Dirac Delta function. Considering the cylinder as a rigid immersion boundary within the flow. First, the flow around a square cylinder was simulated and we surveyed different flow patterns. The changes in the number of Strouhal and the Drag coefficient were investigated in different Reynolds. The flow around the two cylinders was simulated. It was observed that with the increase of Reynolds number and the gap between cylinders, the vortex shedding (Strouhal number) would increase.
2019

Use of One and Two Horizontal Plates to Reduce the Drag Force on the Rigid Cylinder Located Inside the Channel: Approach of the Immersed Interface Method

2019-12
Advances in Science and Technology. Research Journal (القضية : 4) (الحجم : 13)
Immersed interface method is a non-matching boundary approach that has been taken into consideration in recent years. In this method, there is no need to coincide between the fluid and the solid grids. Eulerian grid is used for fluid domain and Lagrangian grid is used for solid domain. Using the Dirac Delta function, the connection between these two grids is established. Separation of the flow from the cylinder surface causes a high pressure drop in some parts of the cylinder, resulting in a dramatic increase in drag force. Drag force reduction is very important in some engineering issues, and several methods have been proposed to achieve this goal. In this study, the flow around a rigid cylinder is simulated. The goal is to reduce the drag force on the cylinder through one and two horizontal plates. The results are in good agreement with prior numerical results.
2015

Liquid sloshing and impact in a closed container with high filling.

2015-04
IWWWFB (القضية : 30) (الحجم : 2015)
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2012

Some Results on a Certain Fractional Boundary Value Problem

2012-07
J. Duhok Univ., (Pure and Eng. Sciences) (القضية : 1) (الحجم : 2012)
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2011

Existence and uniqueness theorem of fractional mixed volterra-fredholm integrodifferential equation with integral boundary conditions.

2011-02
International Journal of Differential Equations (القضية : 2011) (الحجم : 2011)
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2009

The Existence and Uniqueness Solution for Nonlinear System of Fractional Integro-differential Equations

2009-02
J. Duhok Univ., (Pure and Eng. Sciences), (القضية : 1) (الحجم : 2011)
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