AKIŞ KAYNAKLI TİTREŞİMDE İKİ ARDIŞIK SİLİNDİRDEN ELDE EDİLEN GÜCÜN PARAMETRİK OLARAK İNCELENMESİ

Year 2018, Volume: 23 Issue: 1, 329 - 344, 24.04.2018

Erinç Dobrucalı

https://doi.org/10.17482/uumfd.377444

Abstract

Enine akışlarda silindirler özellikle çevri kaynaklı titreşim ve hızlı
artış (galloping) adı verilen bölgeden oluşan akış kaynaklı titreşim
sergilerler. Hızlı artış bölgesinde, osilatörlerde mekanik enerjiye çevrilen
hidrokinetik enerji akışın hızı ve Re sayısıyla artar. Türbülanslı serbest su
yüzeyli kanalda yapılan deneylerde arkalı önlü bulunan ardışık silindirlerin
hareketi 30,000<Re <120,000 aralığında farklı parametreler için
incelenmiş ve özellikle hızlı artış bölgesindeki 0.9<U<1.3 m/s akış hızı
aralığında elde edilen güçte lokal artış ve düşüşler tespit edilmiştir. Bu
çalışmanın amacı bu artış/azalışların sebeplerini açıklamaktır. Bunun için tüm
deneyler incelenerek bu ani değişim olan parametreler (Kütle oranı, yay sabiti,
hız oranı vb. gibi) belirlenerek bir matris oluşturulmuştur. Hem öndeki
silindir hem de arkasındaki silindir için elde edilen güç, genlik oranı,
frekans oranları ve zamana bağlı hareket grafikleri oluşturulmuştur. Yüksek
çözünürlüklü kamera ile görüntüleme tekniği kullanılmış ve elde edilen sonuçlar
tartışılmıştır. Bu değişimlerin ana sebebinin iki silindir arasındaki etkileşim
olduğu tespit edilmiştir. Bu değişimlerde hızlı artış dengesizliği kaybolmakta
ve elde edilen güçte ve genlikte ani düşüşler oluşmaktadır.     

Keywords

Çevri kaynaklı titreşim, hızlı artış dengesizliği, güç

Parametric Investigation of Harnessed Power of Two Tandem Cylinders in Flow Induced Vibration

Abstract

In transverse flow, cylinders respond in FIV (Flow
Induced Vibrations); particularly VIV (Vortex Induced Vibrations) and
galloping. Typically, in the galloping region, the hydrokinetic power converted
to mechanical in the oscillators increases with increasing flow velocity and
Reynolds number. Flow Induced Vibrations (FIVs) of two tandem, rigid and
circular cylinder with end-springs are studied for  30,000<Re <120,000 with different damping,
mass ratio and stiffness as parameters in the Low Turbulence Free Surface Water
(LTFSW) Channel of the Marine Renewable Energy Laboratory (MRELab). Typical
local drops and jumps in harnessed power were observed in the velocity range of
0.9<U<1.3 m/s within the galloping region. The main objective of this
paper is to explain the reason for the presence of these drops and jumps. To
achieve this objective, the points of changing in harnessed power in an
extensive set of data with spacing, damping, stiffness, and flow velocity as
parameters are identified. For both up and downstream cylinders, the harnessed
power, amplitude-ratio, frequency-ratio and time history graphs are obtained to
define the reason of these drop/jumps. Visualization with high-resolution
camera has been used and the assumption which may affect the phenomena were
studied and presented. As a conclusion, there is a big interaction between
cylinders. Galloping instability disappears at this drops and harnessed power
decreases sharply and amplitude as well.

Keywords

Vortex Induced Vibrations, galloping instability, harnessed power

References

• Bernitsas, M. M., and Raghavan, K., (2007), “Reduction/Suppression of Vortex Induced Forces and Motion through Surface Roughness Control,” U.S. Provisional Patent Application No. S2009/0114002 A1 (UofM#3757).
• Bernitsas, M. M., Raghavan K., Ben-Simon Y., Garcia E.M.H., (2008), “VIVACE (Vortex Induced Vibration Aquatic Clen Energy): A New Concept in Generation of Clean and Renewable Energy from Fluid Flow” ASME Paper No. OMAE2008-041101-1. DOI: 10.1115/1.2957913
• Bernitsas, M. M., and Raghavan, K., (2009), “Fluid Motion Energy Converter,” United States Patent and Trademark Office, Patent No. 7,493,759 B2.
• Bernitsas, M. M., and Raghavan, K., (2011), “Enhancement of Vortex Induced Forces and Motion Through Surface Roughness Control,” U.S. Patent Trademark Office, Patent No. 8,042,232 B2.
• Bernitsas, M. M., and Raghavan, K., (2014), “Reduction of Vortex Induced Forces & Motion Through Surface Roughness Control,” U.S. Patent and Trademark Office, Patent No. 8,684,040 B2.
• Bernitsas, M. M., (2016a), Harvesting Energy by Flow Included Motions (Chapter 47), Handbook Ocean Engineering, Springer.
• Bernitsas, M. M., (2016b), Synergistic Flow-Induced Motion of Two Cylinders Harvesting Marine Hydrokinetic Energy, METS 2016.
• Blevins R.D.: Flow-Induced Vibration (Krieger, Florida 1990).
• Bokaian, A., and Geoola, F., (1984), Wake-Induced Galloping of Two Interfering Circular Cylinders, Journal of Fluid Mechanics, Vol.146, p.383–415. DOI:10.1017/S0022112084001920
• Bokaian A., (1989), Galloping of a circular cylinder in the wake of another, J. Sound Vib. 128, 71–85. DOI:10.1016/0022-460X(89)90681-0
• Chang C.C. (2010), Passive turbulence control for VIV enhancement for hydrokinetic energy harnessing using vortex Induced vibrations, Ph.D. thesis. Ann Arbor, MI: The University of Michigan.
• Chang, C. C., and Bernitsas, M. M., (2011), “Hydrokinetic Energy Harnessing Using the VIVACE Converter With Passive Turbulence Control,” ASME Paper No. OMAE2011-50290. DOI:10.1115/OMAE2011-50290
• Ding L, Bernitsas M.M., Kim E.S., (2013), 2-D URANS vs. experiments of flow induced motions of two circular cylinders in tandem with passive turbulence control for 30,000 < Re < 105,000. Ocean Engineering 2013;72:429–40. DOI:10.1016/j.oceaneng.2013.06.005
• Ding L, Zhang L, Kim E.S, Bernitsas M.M., (2015), URANS vs. experiments of flow induced motions of multiple circular cylinders with passive turbulence control. J Fluid Struct;54:612–628. DOI:10.1016/j.jfluidstructs.2015.01.003
• Ishigai S., Nishikawa E., Nishimura E. and Cho K., (1972), Experimental study of structure of gas flow in tube banks axes normal to flow: Part1, Karman Vortex flow from two tubes at various spacings, Bulletin of the Japan Society of Mechanical Engineering, 15(86), 949-956. DOI: 10.1299/jsme1958.15.949
• Kim ES, Bernitsas MM, Kumar AR., (2013), Multi-cylinder flow induced motions: enhancement by passive turbulence control at 28,000 < Re < 120,000. J Offshore Mech Arct Eng 2013;135:021802. DOI: 10.1115/1.4007052
• Kim, E. S and . Bernitsas, M. M. (2016), Performance prediction of horizontal hydrokinetic energy converter using multiple-cylinder synergy in flow induced motion. Applied Energy, 170 (2016) 92–100. DOI: 10.1016/j.apenergy.2016.02.116
• Kinaci O.K., Lakka S., Sun H., Fassezke E., Bernitsas M.M. (2016), Computational and Experimental Assessment of Turbulence Stimulation on Flow Induced Motion of a Circular Cylinder. ASME. J. Offshore Mech. Arct. Eng. 2016;138(4):041802-041802-9. DOI:10.1115/1.4033637.
• Lee J.H, Xiros N, Bernitsas M.M., (2011), Virtual damper-spring system for VIV experiments and hydrokinetic energy conversion. Ocean Engineering;38:732–47. DOI:10.1016/j.oceaneng.2010.12.014
• Lee J.H, Bernitsas M.M., (2011) High-damping, high-Reynolds VIV tests for energy harnessing using the VIVACE converter, Ocean Engineering;38: 1697–712. DOI:10.1016/j.oceaneng.2011.06.007
• NREL: Renewable electricity futures study, Vol. 2, Renewable electricity generation and storage technologies, http://nrel.gov/analysis/re-futures/(2012).
• Park H., (2012), Mapping of Passive Turbulence Control to Flow Induced Motions of Circular Cylinders,Ph.D. dissertation, The University of Michigan.
• Park H, Bernitsas MM, Kumar RA., (2012), Selective roughness in the boundary layer to suppress flow-induced motions of a circular cylinder at 30,000 < Re < 120,000. J Offshore Mech Arct Eng;134:041801. DOI: 10.1115/1.4006235
• Park H, Bernitsas MM, Chang CC., (2013a), Robustness of the map of passive turbulence control to flow-induced motions for a circular cylinder at 30,000 < Re < 120,000. In: Proceedings of the 31st OMAE 2013 conf., Paper #10123, Nantes, France; June 9–14, 2013.
• Park H., Bernitsas M.M., Kumar R.A., (2013b), Enhancement of flow-induced motion of rigid circular cylinder on springs by localized surface roughness at 3.0x104 <Re<1.2x 105. Ocean Engineering; 72:403–15. DOI:10.1016/j.oceaneng.2013.06.026
• Park H, Bernitsas MM, Kim ES., (2013c), Selective surface roughness to suppress flow induced motions of two circular cylinders at 30,000 < Re < 120,000, OMAE2013 10125, June 9-14, 2013, Nantes, France.
• Raghavan, K.,(2007), Energy Extraction From a Steady Flow Using Vortex Induced Vibration, Ph.D. thesis, The University of Michigan, Ann Arbor, MI.
• Richardson A.S., Martucelli J.R., Price W.S., (1965) Research study on galloping of electric power transmission lines, Proc. 1st Int. Conf. Wind Eff. Build. Struct.'65: pp. 612–686.
• Sun, Q., Alam, Md. M., Zhou, Y., (2015a), Fluid-Structure Coupling between Two Tandem Elastic Cylinders, Procedia Engineering, Vol. 126, p.564-568. DOI:10.1016/j.proeng.2015.11.306
• Sun H, Kim E.S, Bernitsas P.M., Bernitsas M.M., (2015b), Virtual spring-damping system for flow-induced motion experiments. J Offshore Mech Arct Eng; 137:061801. DOI:10.1115/1.4031327
• Sun, H., Ma, Ch., Kim, E. S., Nowakowski, G., Mauer, E., Bernitsas, M. M., (2017), Hydrokinetic energy conversion by two rough tandem-cylinders in flow induced motions: Effect of spacing and stiffness, Renewable Energy, 107,61-80. DOI:10.1016/j.renene.2017.01.043
• Unal M.F, Rockwell D., (1988), On vortex formation from a cylinder, Part 1: The initial instability, J. Fluid Mech. 190, 491–512. DOI:10.1017/S0022112088001429
• Wu W, Bernitsas MM, Maki K., (2011), RANS simulation vs. experiments of flow induced motion of circular cylinder with passive turbulence control at 35,000 < Re < 130,000. In: ASME 2011 30th International conference on ocean, offshore and arctic engineering, Rotterdam, The Netherlands. DOI: 10.1115/1.4027895
• Wu W., (2011), Two-dimensional RANS simulation of flow-induced motion of circular cylinder with passive turbulence control. Ph.D. thesis, University of Michigan.
• Xu G., Zhou Y., (2004), Strouhal numbers in the wake of two inline cylinders, Experiments in Fluids 37, 248-256. DOI:10.1007/s00348-004-0808-0
• Zhou Y., Yiu M.W., (2006), Flow structure, momentum and heat transport in a two tandem cylinder wake. Journal of Fluid Mechanics 548, 17-48. DOI:10.1017/S002211200500738X
• Zdravkovich, M.M., (1987), The effects of interference between circular cylinders in cross-flow, Journal of Fluids and structures, 239-261. DOI:10.1016/S0889-9746(87)90355-0
• Zdravkovich M.M.: Flow Around Circular Cylinders, Vol. 1 (Oxford Univ. Press, Oxford 1997)
• Zdravkovich M.M.: Flow Around Circular Cylinders, Vol. 2 (Oxford Univ. Press, Oxford 2002)
• Vikestad K., Vandiver J.K., and Larsen C.M., (2000), Added Mass and Oscillation Frequency for a Circular Cylinder Subjected to Vortex-Induced Vibrations and External Disturbance, J. Fluids Struct., 14(7), pp. 1071–1088. DOI:10.1006/j#s.2000.0308