This work aims to improve the visualization of a subsonic open section type smoke tunnel, which already exists in the AL-Nahrain University/College of Engineering/Mechanical Department Laboratory. This study focuses on modifying the contraction section only to improve the airflow properties in the test section. A numerical study with ANSYS FLUENT R19.0 was carried out to characterize the flow via the contraction section. The parameters that are suggested to be modified are the wall profile and the length of the contraction section. The analysis includes the original contraction section and suggested new profiles to be compared under the same boundary conditions. The new suggested profiles for this work are polynomials of orders (6th, 7th, 8th, 9th, and 10th). A unique analysis is achieved for the 9th order profile, where it is tested with four different inflection points (0.5L, 0.55L,0.6L, and 0.65L). The study focuses on the uniformity, turbulence intensity, boundary layer thickness at the contraction section exit plain, beside the boundary layer separation along with the contraction as comparing parameters. Experimental work was done to validate the numerical results. The experiment work includes building a half-scale of the original smoke tunnel to monitor the new contraction’s direct influence on the test section’s flow. The result showed that the 9th-order wall profile with an inflection point at 0.65L and length of 0.93m is the pest contraction for the aimed smoke tunnel.

The present work examined numerically for the first time, the magneto-hydrodynamics (MHD) natural convection flow and heat transfer in a fully opened parallelogrammic enclosure filled with copper-water nanofluid and subjected to a straight magnetic field. Both the upper and lower inclined walls of the enclosure are kept cold, while its right sidewall is considered fully opened to the environment. The left sidewall of the enclosure is heated partially, while the remaining parts of it are considered thermally insulated. The ranges of this study are, Hartmann number (0  Ha  75), nondimensional heat source location (0.25    0.75), Rayleigh number (10 4  Ra  10 6), solid volume fraction (=0.04), and the inclination angle of the upper and the lower walls (-60°    60°). The non-dimensional heat source length is considered fixed at [ = 0.25]. For all Hartmann numbers, It was found that for [Ra =10 6 ] , the maximum

Energy is an essential ingredient for socioeconomic development and economic growth country. Energy is available in two different forms, fast depleting or non-renewable (coal, fuel, natural gas) and renewable (solar, wind, hydro etc.). In fact, one of the biggest sources of energy is all around us all of the time, the wind. Every year the number of installed wind power plants in the world increases. Vertical axis wind turbines (VAWT) are capable of producing a lot of power, and offer many advantages for small-scale and domestic applications. One drawback of Darrieus Type VAWT is their inability to reliably self-start at a low tip speed ratio [1]. The main purpose of the study described here is to investigate the effect of different designparameter on performance evaluation of SB-VAWTs.

In this paper, experimental and numerical investigations were carried out to evaluate the drag force of a combined frame with movable vanes. For this purpose, the combined frame model was developed from a flat plate with three movable vanes and one Darrieus straight bladed NACA0012. A straight-bladed Darrieus NACA0012 airfoil is attached at the tip of the model structure. The design increases the starting and total torque of the model on the side, which rotates to wind direction, hence increasing the drag coefficient  and reduces the negative torque on the other side of the frame that rotates opposite to the wind. Combined frame in experimental work is tested in the subsonic wind tunnel to analyze the performance parameters like drag force   and drag coefficient . The frame is tested under different wind speed ranging from 4 m/s to 28 m/s, test results show the reliable and efficient performance. The results indicated that the maximum drag force  for the combine frame is 6 N at experimental work and 5.649 at numerical simulation under the same condition (wind speed V=28 m/s and azimuth angle θ = 90°). Computational Fluid Dynamic software (CFD) ANSYS FLUENT is used in this simulation which is carried out for the combined frame to investigate the drag force and drag coefficient, The finite volume method with Shear Stress Transport (STT), k-  turbulence model is used, the predicted results show that the flow through the combined frame at the negative side when all the vanes are freely open. The static pressure drops across the combined frame when the combined frame rotates to the negative side and the resistance of the combined frame to the flow decreased. This case helps to increase turbine angular velocity  and this leads to an increase in the power coefficient of the turbine.

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