الفهرس 
Wind Energy in Urban EnvironmentOnly 14 pages are availabe for public view
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Abstract
There is a growing interest in the development of sustainable buildings to overcome the degradation of the natural environment by minimizing the carbon footprints of buildings. This goal can be achieved by incorporating renewable energy generation systems into buildings. A promising option is to resort to a Savonius rotor to energize the urban environment. This work introduces an investigation on the performance of Savonius wind-turbine rotor integrated within a building tunnel. Numerical simulations
are performed here and validated by measurements conducted on a wind turbine installed within a duct (ducted turbine) and un-ducted one. For performing the experimental work, a free air jet test rig, built at the laboratory of advanced fluid mechanics of the faculty of
engineering, Menoufia University, is used. The simulations are based on the three dimensional incompressible Unsteady Reynolds-Average Navier-Stokes (URANS) equations that are solved by employing ANSYS Fluent 17. The turbulence model used in this study is the RNG k–ε turbulence model based on the recommendations of different publications. The performance of Savonius rotor is firstly examined via experimental measurements and numerical simulations for the ducted turbine at three different axial positions, in
addition to the un-ducted condition. The results are compared for various wind-speed values namely, =5.5, 7.3, 8.5, and 10 m/s. The peak performance is achieved where the
turbine is located at the middle of the duct length, with an increase in maximum power coefficient ( ) of 18.9 % as compared to the performance of un-ducted one. Performance enhancement of the ducted turbine (Savonius rotor) is also carried out using an obstacle plate upstream the rotor. The obstacle plate shields the convex blade of the
Savonius turbine and leads to a better flow orientation toward the concave blade. Furthermore, the static torque, a measure of the rotor starting ability, can be improved. Introducing a 35⁰-inclined plate upstream of the ducted rotor increases the rotor performance, with an increase in of 23.5 % as compared to the performance of unducted rotor. The numerical results are found to have good prediction compared to th present measurements. The static torque in the case of the 35⁰-inclined has positive values at all rotor orientations (rotation angles) which ensures good starting ability of the present modification. Based on the confidence of CFD, numerical simulations are extended to study the performance of wind turbine rotor integrated within a building tunnel. The effect of the tunnel width relative to building breadth is investigated. The results show that the inclusion of building side-width to the tunnel significantly improves the rotor performance. The best width ratio is w/W= 1/9, where w is the tunnel width and W is the building width, which achieves 45 % increase in the as compared to the ducted rotor. Moreover, the effect of the tunnel location through the building model is
investigated to attain the best performance and consequently the maximum power generation from the wind. The reasons behind either the degradation or improvement of the wind turbine performance are explored based on the flow behavior including pressure distribution and velocity streamlines through the building tunnel. The numerical results demonstrate the role of vortices evolution on the rotor performance. The maximum performance of the ducted Savonius rotor in terms of is reached by integrating the rotor within a building tunnel at the best tunnel location far from the center of the building, with a 83.6% increase in the, as compared to ducted rotor. Significant effect of the obstacle plate is observed on the performance of the rotor Savonius integrated within a building tunnel. The peak value of records 37.2 % at tip speed ratio(λ=1) and free wind speed of 10 m/s. The corresponding increase in 95.7 % as compared to the performance of the ducted rotor.