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Grinding is a widely used manufacturing method in state of art industry. By realizing needs of manufacturers, grinding parameters must be carefully selected in order to maintain an optimum point for sustainable process. Surface roughness is generally accepted as an important indicator for grinding parameters. In this study, effects of grinding parameters to surface roughness were experimentally and statistically investigated. A complete factorial experimental flow was designed for three level and three variable. 62 HRC AISI 8620 cementation steel was used in grinding process with 95-96% Al2O3 grinding wheel. Surface roughness values (Ra, Rz) were measured at the end of process by using depth of cut, feed rate and workpiece speed as input parameters. Experimental results were used for modeling surface roughness values with linear, quadric and logarithmic regressions by the help of MINITAB 14 and SPSS 16 software. The best results according to comparison of models considering determination coefficient were achieved with quadric regression model (84.6% for Ra and 89% for Rz). As a result, a reliable model was developed in grinding process which is a highly complex machining operation and depth of cut was determined as the most effective parameter on grinding by variance analysis (ANOVA). Obtained theoretical and practical acquisitions can be used in various areas of manufacturing sector in the future.

It is shown that the numerical and experimental results have a good agreement in respect of the instantaneous and time-averaged flow field patterns of vorticity, velocity component streamwise direction and streamline topology. In addition, drag coefficient of the geometries were also numerically calculated. For all geometries the wake length in x and y directions and size of the foci of the streamlines are decreasing by increasing Reynolds numbers in time-averaged results. The time-averaged flow patterns of both experimental and numerical results have considerable symmetry with respect to the centerline of each cylinder. Contours of the time-averaged stream wise velocity for Re=10000 demonstrate that the stagnation point around the symmetry plane moves further upstream for all cylinders in accordance with Re=5000. The maximum drag coefficient value was yielded for the square cross-section cylinder as 1.78 due to the sharp-edged geometry.

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In this work, equations that govern axisymmetric incompressible turbulent flow for heat transfer calculations are derived assuming constant thermo-physical properties and a specific nondimensionalization scheme. Vector algebra is used for expanding vector form of governing equations in cylindrical coordinate system. Emphasis is on the derivatives of unit vectors according to azimuthal direction. Reynolds decomposition is used for separating time averaged terms and Reynolds Stress terms. Standard k-ϵ turbulence model is selected for solving closure problem due to the Reynolds stresses. Organization of the governing equations after model inputs is done explicitly. Also, parameters that constitute nondimensionalization scheme are given. Evaluations of the complete process are given. Two major aims of the work are presenting necessary equations explicitly and revealing some key steps for reorganization of the equations. It is also aimed to present novel illustrations in order to contribute comprehension of the concepts.