Boyuna yivli pürüzlülüğün akımın boruya uyguladığı sürükleme kuvveti üzerine etkisi

Bu çalışmada, boru dış yüzeyine yerleştirilen boyuna yivli pürüzlülüğün, boruya etkiyen sürükleme (direnç) kuvveti üzerindeki etkisi deneysel olarak incelenmiş ve üniform kum pürüzlülük ile karşılaştırılmıştır. Deney neticeleri göstermiştir ki, boruya etkiyen sürükleme kuvveti borunun tabanla olan mesafesi ve pürüzlülük elemanlarının yüksekliği arttıkça artarken, yiv genişliği azaldıkça azalmaktadır. Ayrıca aynı yükseklikteki boyuna yivli pürüzlülük ve üniform kum pürüzlülük elemanlarına sahip boruya etkiyen sürükleme kuvvetleri arasında bir miktar fark olduğu görülmüştür.

Effects of longitudinal groove-roughness elements on the drag force exerted by the flow on a pipe

In this study, the effects of the longitudinal-groove roughness elements (placed on the outer surface of the pipe) on the drag force acting on the pipe were experimentally investigated and compared with uniform sand roughness. The experimental results have indicated that the drag force exerted by the flow on a pipe increases as the distance between the canal bottom and the pipe and the height of roughness elements increases and it decreases as the distance between two successive longitudinal-groove roughness elements decreases. The experiments have also shown that there is some difference between the drag forces corresponding to longitudinal-grove roughness elements and uniform sand roughness elements for the same height.

PDF

___

1. Teng, C.C. ve Nath, J. H., “Forces on Horizontal Cylinder Towed in Waves”, Journal of Waterway, Port, Coastal and Ocean Engineering, ASCE, Cilt 111, No 6, 1022-1040, 1985.
2. Pranesh, M.R.R. ve Man, J.S., “Wave – Tubular Member – Wave and Current Interaction”, Journal of Waterway, Port, Coastal and Ocean Engineering, ASCE, Cilt 115, No 6, 760-774, 1988.
3. Ballet, J.P. ve Hobbs, R.E., “Asymmetric Effects of Prop Imperfections on the Upheaval Buckling of Pipelines”, Thin-Walled Structures, Cilt 13, No 55, 355-373, 1992.
4. Fredsoe, J. ve Sümer, B. M., “ Bed Shear Stress Measurements over a Smooth Bed in Three- Dimensional Wave – Current Motion”, Coastal Engineering, Cilt 20, No 34, 277-316, 1993.
5. Fredsoe, J. ve Sümer, B.M., “Sinking/ Floating of Pipelines and Other Objects in Liquefied Soil Under Waves”, Coastal Engineering, Cilt 38, 53- 90, 1999.
6. Fredsoe, J. ve Sümer, B.M., “Onset of Scour Below Pipelines and Self-burial”, Coastal Engineering, Cilt 42, No 4, 313-335, 2001.
7. Wu Y.T. ve Riha, D.S., “Reliability Analysis of On-Bottom Pipeline Stability”, 8th American Society of Civil Engineer Special Conference on Probabilistic Mechanics and Structural Reliability, University of Notre Dame, Chicago, 312-325, 23-26 Temmuz 2000.
8. Çokgör, S. ve Avcı, İ., “Hydrodynamic Forces on Partly Buried Tandem, Twin Pipelines in Current”, Ocean Engineering, Cilt 28, No 10, 1349-1360, 2001.
9. Çokgör, S., “Hyrodynamic Forces on Partly Buried Cylinder Exposed to Combined Waves and Current”, Ocean Engineering, Cilt 29, No 7, 753- 768, 2002.
10. Çokgör, S. ve Avcı İ., “Forces on Partly Buried Tandem Twin Cylinders in Waves at Low Keulegan-Carpenter Numbers”, Ocean Engineering, Cilt 30, No 12, 1453-1466, 2003.
11. Alexandrou A., Principles Of Fluid Mechanics, Prentice Hall, New Jersey, 2000.
12. Gündemir, O., Su Altı Borularına Etkiyen Kuvvetler, Yüksek Lisans Tezi, Gazi Üniversitesi, Fen Bilimleri Enstitüsü, 2006.
13. Kalghatgi, S.G. ve Sayer, P.G., “Hydrodynamic Forces on Piggyback Pipeline Configurations”, Journal of Waterway, Port, Coastal and Ocean Engineering, Cilt 123, No 1, 16-22, 1997.
14. Mouselli, A.H., Offshore Pipeline Design, Analysis and Methods, PennWell Books Company, 33-43, 1981.