Title :
Square-cylinder flow patterns modulated using an upstream control rod
Author :
Yen, Shun C. ; Wu, Sheng F.
Author_Institution :
Dept. of Mech. & Mechatron. Eng., Nat. Taiwan Ocean Univ., Keelung, Taiwan
Abstract :
This investigation examines the flow patterns, vortex-shedding frequency and aerodynamic performance of a combination of an upstream control rod and a square cylinder. The flow behaviors were tested using various Reynolds numbers, rotation angles and spacing ratios. The smoke-wire scheme was utilized to visualize the flow structures. Particle image velocimetry (PIV) was applied to analyze the global velocity fields and streamline patterns. A hot-wire anemometer was used to probe the vortex-shedding frequency behind the control rod and the square cylinder. Moreover, a linear pressure scanner was employed to measure the surface pressure on the square cylinder. Accordingly, the aerodynamic parameters were determined using the surface-pressure profiles. Three characteristic flow modes - single, attached and bi-vortex-street - were categorized by varying the Reynolds number and space ratio. In the attached mode, the upstream control rod dominated the flow behaviors. Furthermore, in the attached mode, the experimental data indicate that the drag was 57% lower than that without the upstream control rod.
Keywords :
aerodynamics; flow visualisation; pattern formation; pressure measurement; vortices; Reynolds number; aerodynamic parameter; bivortex-street analysis; flow aerodynamic behavior; flow behavior; flow mode characteristics; global velocity field; hot-wire anemometer; particle image velocimetry; rotation angle; square-cylinder flow pattern; streamline pattern field; surface pressure measurement; surface-pressure profile; upstream control rod; vortex-shedding frequency; Aerodynamics; Fluid flow measurement; Visualization; Control rod; PIV; Smoke wire; Vortex shedding;
Conference_Titel :
Communication Software and Networks (ICCSN), 2011 IEEE 3rd International Conference on
Conference_Location :
Xi´an
Print_ISBN :
978-1-61284-485-5
DOI :
10.1109/ICCSN.2011.6014892