Active Control of Vortex Shedding Frequency by Side-Jets

当一个模糊的身体被放置在一个流动中，身体就会在身体后面产生一个单独的流动区域。它导致了涡流的一代，它在水流中生长，并被淹没在觉醒中。如果身体的正常频率与涡流遮蔽频率相对应，锁定（对称振动）是不可避免的，那么就导致了对身体的大损害。因此，如果涡流遮蔽频率可以被控制，那么它在工程中就会非常有用;这是一种调查方法，使用侧面的控制方法--没有喷气机可以应用于调查，当涡流遮蔽频率可以被控制或不被控制。这里的侧面-喷气机在点上被淹没了，在那里的分离线被生成了。在控制涡流遮蔽频率、两者之间的数值模拟和实验的情况下，对侧喷射的性能进行了表征。结果被归纳为如下所示：在统一吸收侧喷射的情况下，这种特征表明，涡流遮蔽频率在某些窄范围内发生了变化，而与侧喷射速度的变化。吸入侧-喷气机对流动场和涡流的频率比注入侧-喷气机都有更有效的影响。

When a bluff body is placed in a flow, the body generates a separated flow region behind the body. That causes the generation of a vortex, which is grown along the flow, and shed into the wake. If the eigen frequency of the body corresponds to the vortex shedding frequency, the lock-in (sympathetic vibration) is occured, that is caused large damages to the body. Therefore, if the vortex shedding frequency could be controlled, it would be very useful in engineering.It this investigation, the control method using side-jets without any other new construction was applied to investigate whether the vortex shedding frequency can be controlled or not. Here the side-jets were inhaled at the point where the separation shear layr was generated. With emphasis on the performance of side-jets on the control of the vortex shedding frequency, both numerical simulation and experiment were carried out.The results are summarized as follows :・In the case of uniform suction side-jets, the characteristic is shown that the vortex shedding frequency is changed immediately in some narrow range with the change of side-jets velocity.・Suction side-jets have more effective influence on both the flow field and the vortex shedding frequency than injection side-jets.