Long-term wind speed data for thirteen meteorological stations, measured over a five-year period, were statistically analyzed using the two-parameter Weibull distribution function. The purpose of this study is to reveal for the first time the wind power potentials in Chad and to provide a comprehensive wind map of the country. The results show that the values of the shape and scale parameters varied over a wide range. Analysis of the seasonal variations showed that higher wind speed values occur when the weather condition is generally dry and they drop considerably when the weather condition is wet. It was also observed that the wind speed increases as one moves from the southern zone to the Saharan zone. Although the wind power at each site varies significantly, however, the potentials of most of the sites were encouraging. Nevertheless, according to the PNNL classification system, they are favorable for small-scale applications only. A few stations in the middle of Sudanian and Sahel regions are found to be not feasible for wind energy generation due to their poor mean wind speed. The prevailing wind direction for both Saharan and Sahel regions is dominated by northeastern wind, while it diverged to different directions in the Sudanian zone.

Ram Air Turbine (RAT) is used as an emergency power source to feed vital apparatuses required for aircrafts in case of main systems failure. The purpose of this paper is to explain the function of RAT as a wind harvesting technology for aircraft and its advantages as auxiliary power generator during landing process. This survey allows a more axiomatic understanding on the use of different RAT approaches in aircraft construction. The survey in this paper also provides a sight to simultaneously use RAT for emergency case and power harvesting as future energy.

The present paper aims to study the possibility of dispensing an auxiliary power unit (APU) in an aircraft powered by fossil fuels to reduce air pollution. It particularly seeks to evaluate the amount of power generated by the ram air turbine (RAT) using the novel counter-rotating technique while characterizing its optimum axial distance. The ram air turbine (RAT), which is already equipped in aircrafts, was enhanced to generate the amount of energy produced by the APU. The approach was implemented by a CRRAT system. Six airfoil profiles were tested based on 2D models and the best airfoil was chosen for implantation on the RAT and CRRAT systems. The performance of the conventional single-rotor RAT and CRRAT were analyzed using FLUENT software based on 3D models. The adopted numerical scheme was the Navier–Stokes equation with k–ω SST turbulence modeling. The dynamic mesh and user-defined function (UDF) were used to revolve the rotor turbine via wind. The results indicated that the FX63-137 airfoil profile showed a higher performance in terms of the lift-to-drag ratio compared to the other airfoils. The optimum axial distance between the two rotors was 0.087 m of the rotor diameter and the efficiency of the new CRRAT increased to almost 45% compared to the single-rotor RAT.

Comparison of six airfoils; FX 63-137, FX76-100, S835, S809, NACA63415, and NACA63215, have been performed using commercial software, FLUENT and XFOIL, in order to choose the best maximum lift to drag ratio in the region of 4×10^∧6 Reynolds number, and also to specify their aerodynamic coefficients in Blade Element Momentum theory (BEM). These airfoils are candidates for the use as blade turbines and another application of flying object operating at high Reynolds number. In this study, the two-dimensional model of airfoils was established through Gambit software. The range of angles of attack is from -150 to 150. Comparisons of the numerical results generally show good agreements. Numerical results of FX 63-137 were also validated with experimental data. A good agreement of lift and drag coefficient from numerical simulations of FLUENT and experimental data was obtained at 10^∧6 Reynolds number.