Effects of Marine Growth on Hydrodynamic Coefficients of Rigid Tubular Cylinders

Article Preview

Abstract:

In this paper the wave induced hydrodynamic forces and the corresponding hydrodynamic coefficients for a 42 mm diameter model pipe subjected to regular waves was investigated experimentally and the results were compared with the responses of a similar rigid cylinder fitted with marine growth. The main objective of this study was to quantify the effects of marine growth on the hydrodynamic forces experimentally and determine the associated hydrodynamic coefficients. The experimental data were generated from a set of wave tank model tests and the results were scaled up using a scale factor of 1:55. The thickness of marine growth applied on the model pipe was varied with respect to the water depth in the ratio of 3:2:1. Regular waves were generated with wave heights ranging from 0.02 m to 0. 2 m for modal period varying from 0.6 s to 3.25 s. The tests were conducted for Keulegan-Carpenter number ranging from 3.9 to 23.3. The findings of the experimental results revealed that increasing the thickness of the full scale prototype cylinder by 110 mm due to marine growth fittings, has increased the overall wave hydrodynamic forces by 16 to 90% depending on the wave heights and the wave frequencies at which the model was tested, proving that the drag coefficients have considerably increased.

You might also be interested in these eBooks

Info:

Periodical:

Pages:

247-252

Citation:

Online since:

June 2014

Export:

Price:

* - Corresponding Author

[1] Norsok, Actions and action effects, in Standards Norway, N-003, Edition. (2007).

Google Scholar

[2] Wolfram, J. and A. Theophanatos. The effects of marine fouling on the fluid loading of cylinders: some experimental results. in Offshore technology conference. (1985).

DOI: 10.4043/4954-ms

Google Scholar

[3] PTS, Petronas Technical Standards, in Design of Fixed Offshore Structures. (2012).

Google Scholar

[4] API, R., RP 2A-WSD, (2007). Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platform-Working Stress Design. 2007, API Publishing Services, Washington, DC.

DOI: 10.4043/23558-ms

Google Scholar

[5] Chakrabarti, S.K., Hydrodynamics of offshore structures: Mathematical theory and its applications in structures. (1987).

Google Scholar

[6] Morison, J., J. Johnson, and S. Schaaf, The force exerted by surface waves on piles. Journal of Petroleum Technology, 1950. 2(5): pp.149-154.

DOI: 10.2118/950149-g

Google Scholar

[7] Sarpkaya, T. Hydrodynamic forces on various multiple-tube riser configurations. in Offshore Technology Conference. (1979).

DOI: 10.4043/3539-ms

Google Scholar

[8] Chakrabarti, S.K., Hydrodynamic coefficients for a vertical tube in an array. Applied Ocean Research, 1981. 3(1): pp.2-12.

DOI: 10.1016/0141-1187(81)90080-8

Google Scholar

[9] Sarpkaya, T. In-Line and Transverse Forces, On Cylinders in Oscillatory Flow at High Reynolds Numbers. in Offshore Technology Conference. (1976).

DOI: 10.4043/2533-ms

Google Scholar

[10] Sarpkaya, T., Forces on a circular cylinder in viscous oscillatory flow at low Keulegan-Carpenter numbers. Journal of Fluid Mechanics, 1986. 165(61-71): pp.11-15.

DOI: 10.1017/s0022112086002999

Google Scholar

[11] Justesen, P., Hydrodynamic forces on large cylinders in oscillatory flow. Journal of Waterway, Port, Coastal, and Ocean Engineering, 1989. 115(4): pp.497-514.

DOI: 10.1061/(asce)0733-950x(1989)115:4(497)

Google Scholar

[12] Chakrabarti, S.K., Wave Force Coefficients for Rough Vertical Cylinder. Journal of Waterway, Port, Coastal, and Ocean Engineering 1984. Vol. 110( No. 1): pp.101-104.

DOI: 10.1061/(asce)0733-950x(1984)110:1(101)

Google Scholar

[13] Bryndum, M., V. Jacobsen, and D. Tsahalis, Hydrodynamic forces on pipelines: Model tests. Journal of Offshore Mechanics and Arctic Engineering, 1992. 114: p.231.

DOI: 10.1115/1.2919975

Google Scholar

[14] Sumer, B. and J. Fredsoe, Hydrodynamics around Cylindrical Structures, (1997). World Scientific, Singapore.

Google Scholar

[15] Sarpkaya, T. Hydrodynamic Lift and Drag on Rough Circular Cylinders. in Offshore Technology Conference. (1991).

DOI: 10.4043/6518-ms

Google Scholar

[16] Idichandy, V. (2001). Strain-gauge-based force transducers in hydrodynamic research. Paper presented at the Second International Conference on Experimental Mechanics.

DOI: 10.1117/12.429602

Google Scholar