Abstract

We experimentally investigated the potential of a trip wire as a passive control mechanism for controlling flow-induced vibration (FIV) of a three-dimensional bluff body. The effect of a surface trip wire was investigated for varying diameter ratio in the range 1.3×10−2⩽k/D⩽6.7×10−2, where k is the wire diameter and D is the sphere diameter, and trip-wire location in the range 20∘≤ϕ≤60∘, where the angle ϕ was measured from the leading stagnation point. The FIV response of the sphere is characterised for a wide range of reduced velocities 3⩽U∗⩽20, defined as U∗=U/fnwD, where U is the free stream velocity and fnw is the natural frequency of the system in water. It was found that for a fixed trip-wire diameter ratio, the vibration amplitude decreased progressively with increasing ϕ. Furthermore, the synchronisation regime became narrower, and the mode II and the plateau branches of the FIV response occurred for lower reduced velocities, compared to those for a smooth sphere. The control was highly effective for high reduced velocities (U∗>10) with a maximum reduction of up to 97.8% for ϕ=60∘. Interestingly, thicker trip wires (k/D>1.3×10−2) were effective in disrupting Mode I, but induced a galloping-like response for higher reduced velocities. Tripping proved to be an effective passive control strategy for spheres, with the optimal trip-wire size varying across Mode I to Mode III.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.