Exploiting the Coandă effect for wind-driven reciprocating RO desalination

Wind Energy Generation by Forced Vortex Shedding

“…By comparing both figures we observe the performance drawback that is associated with  limitation specifically for higher momentum coefficient values, where as we increased  range a dramatic increase in system performance was observed. These simulation results clearly identify the reason for the relatively low CoRe system power coefficients [26]. The system was operated at a frequency (0.95Hz) that was approximately one half of the optimum frequency.…”

“…Therefore, to calculate system efficiency, evaluation of the power invested in applying the ASB and the power extracted from the flow is required. The CoRe device [24][25] [26] is comprised of a sting-mounted cylinder on a pivot that is counterbalanced by tension springs which has one degree of freedom (1-DOF), free to rotate about a pivot. The system's center of mass is located above the rotation axis and it is only the springs that hold it balanced.…”

“…was found for both cases that the optimal performance obtained at system linear natural frequency of about 1.8Hz achieving 23%-25% net power coefficient. It was noted that this frequency is about double the linear natural frequency of the laboratory demonstrator tested in [26]. In addition, performance evaluation of 2 Hz system linear natural frequency was simulated at three different wind speeds 3.2 m/s, 5.3 m/s and 6.4 m/s and maximum power coefficient of 23%, 13.5% and 9.2% was obtained respectively.…”

“…More recently, our group developed the so-called Coandă-based Reciprocating (CoRe) system [24] where alternating slot blowing at 0.05 e St  was applied alternately on the sides of a circular cylinder, for the purpose of developing a wind energy device (see Video). This concept is particularly effective as a high-torque device [25] that was demonstrated as a means of driving piston pumps for water desalination [26]. In all of these studies, the periodic active flow control frequency was very close to the system fundamental frequency, but significantly less than the natural shedding frequency, with resulting modest efficiencies 4%.…”