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Go to Editorial ManagerA wind tunnel is a piece of equipment specifically designed for studying the influence of air passing over solid matters in aerodynamic research. Computational Fluid Dynamics (CFD) was used to conduct methodical research into the design and modeling of flow characteristic in a closed-loop wind tunnel. The necessary intake fan velocity was established using an analytical velocity model, and the test section's inlet conditions were produced by applying the Reynolds number equation, assuming that the Reynolds number was 500,000. Instead than using the traditional method, a full-scale CFD model of the complete wind tunnel was taken into consideration. This made it possible to improve the flow quality over the entire circuit as well as only in the test area. The test section flow quality was more impacted by upstream flow circumstances than downstream conditions, according to analysis of the guide vane designs. Therefore, careful consideration has to be done while constructing the vanes at upstream curves, especially corners that are parallel to the test section. The simulation results showed that, in the case of a fully configured wind tunnel, flow uniformity in the test section is successfully attained.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
This experimental research depicts the role of coating hot surfaces by graphite and graphene on the process of heat dissipation from these hot surfaces. Three aluminum specimens have been prepared for test, one of theme is coated by graphite, another one by graphene a while the third is left free of coating for comparison purpose. Each specimen is tested separately in a home-made wind tunnel. A plate electrical heater is adhered on the bottom of the specimen to simulate the generated energy by a heat sink. A heat sink composed of high thermal conductivity was applied between the heater plate and the base plate of heat sink to reduce the contact resistance to heat flow. The experiments are conducted with four turbulent Reynolds number. The results reveal that the sample coated by graphene exhibits the best thermal dissipation while the uncoated specimen shows the worst thermal performance.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
The performance of a five-holed conical probe ( which has a conical head with four holes symmetrically placed on the cone surface and one at the truncated tip) for the measurements of fluid velocity in three dimensional incompressible flow was investigated in air in an open circuit subsonic wind tunnel . The air velocity ranged from 15 – 45 m/s and the Reynolds number ranged from 40000 to 100000 based on the cone base diameter. The methods of calibration and use of the probe are given where the measurements of one angle and three pressures are sufficient to give the three components of velocity, static and total pressure. The conical head probe is easier to manufacture than the spherical head probe and has the advantage of having clear fluid separation points at the cone base whereas the fluid separation on the spherical probe is not well defined and depends on the Reynolds number.