Fluid-elastic excitation in heat exchanger tube bundles. Final report
- Oklahoma State Univ., Stillwater, OK (United States). School of Mechanical and Aerospace Engineering
The present research is concerned with the instability of flow around a single cylinder, a normal cylinder pair, a tube row, and four-row tube arrays in cross flow. Flow visualization by dye injection technique was used to highlight the important features and structures of the flow field. A hot-film anemometer with the help of high speed data acquisition was used to perform measurements of the time-mean velocity, turbulence intensity, and vortex shedding frequency in the flow field of interest. Complex instability was observed in and behind closely-spaced tube rows and tube arrays. It was caused by the emerging jets grouping, with the flow pattern switching from one quasi-stable pattern to another one at irregular time intervals. Lock-in behavior of a single cylinder and a normal cylinder pair was also investigated. Slanted onion-shaped lock-in boundaries for a single cylinder with transverse force vibration were discovered. The lock-in behavior of a large pitch-ratio cylinder pair is similar to that of the single cylinder. For closely spaced cylinder pair, the lock-in region for even-numbered superharmonic of the shedding frequency are dominant. This phenomenon is in contrast to the single cylinder case, which has lock-in for odd-number superharmonic.
- Research Organization:
- Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Oklahoma State Univ., Stillwater, OK (United States). School of Mechanical and Aerospace Engineering
- Sponsoring Organization:
- Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 95194
- Report Number(s):
- EPRI-TR-103507; TRN: 95:006285
- Resource Relation:
- Other Information: PBD: Jul 1995
- Country of Publication:
- United States
- Language:
- English
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