| The issue of a flluid past circular cylinder involves a very wide range ofpractical engineering significance, such as wind-induced vibration of long-spancable. The phenomenon of vortex shedding is the main cause of fluctuating lift andvortex-induced vibration (VIV). This paper partly investigates the flow controleffects of lift and drag, suppressing vortex shedding and ampltitude of VIV via thesteady suction method, in the subcritical regime. Parametric variation and themechanism of the steady suction method are also studied. The main contents of thispaper can be devided as follows:(1) Numerical models of steady suction control are set up and rationality ofnumerical models under normal condition is verified.(2) Such parametric variations as hoop layout, suction flow rate and axialdistribution of suction holes are investigated in terms of their effects on suctionmethod. It is found that hoop location of suction hole is critical,90°contributingbest. Under several specific suction conditions, increase of suction flow rate resultsin improvement of control effect. However, when suction flow rate reachs thespecific value, control effect will not enhanced with suction velocity. In spite of thesame equivalent momentum coefficient, the axial spacing mode of suction holeswith smaller and larger distances alternatedly distributed and another one withsmalle distances uniformly distributed display better.(3) The study of mechanism of the above flow control is conducted. Effecientcontrol method lies in suppressing the periodic vortex shedding and controlling thedevelopment of axial flow.(4) CFD simulation of VIV and application of steady suction method to VIV iscarried out. It is found that the method is also effective to control the amplitude ofdisplacement and periodic vortex-shedding. |
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