Ali DOĞU, Kubilay CİHAN, Ayse YUKSEL OZAN, Osman YILDIZ, Hayri ATEŞ

Düşey Yüzlü Duvar Önünde Pervane Jetinin Neden Olduğu Oyulma

Gemilerin seyir ve manevraları sırasında deniz tabanında meydana gelebilecek oyulmalar, önlem alınmadığı takdirde ciddi sorunlara neden olabilir. Oluşacak oyulmaların tahmini liman yapılarının stabilitesi için büyük önem taşımaktadır. Bu çalışmada, düşey yüzlü bir duvar önünde oluşan oyulma deneysel olarak incelenmiştir. Bu amaçla, 3.2x2.0x1.0 m ölçülere sahip deney tankının tabanına ortalama elek çapı d50= 0.24 mm ve özgül kütlesi ρ=2650 kg/m3 olarak belirlenen kuvars kumu serilmiştir. Deneylerde 0.06 m çaplı pirinçten imal edilmiş bir pervane kullanılmıştır. Pervane kendi ekseni ile polikarbon esaslı düşey yüzlü bir duvar arasında 4 farklı konumda yerleştirilmiş ve 3 farklı dönüş hızında çalıştırılmıştır. Hız ölçümleri Akustik Doppler prensibi ile çalışan ADVP kullanılarak elde edilmiştir. Düşey yüzlü duvar ile pervane ekseni arasındaki mesafenin ve pervane dönüş hızının oyulma mekanizması üzerindeki etkilerine dair bulgular literatürdeki çalışmalarla karşılaştırılmıştır.

Anahtar Kelimeler:

Oyulma, Düşey yüzlü duvar, Pervane jeti, Sınırlandırılmış oyulma

Scour Induced by Propeller Water Jet in front of a Vertical Wall

Scours that may occur on the sea floor during the navigation and maneuvers of ships can cause serious problems if precautions are not taken. The estimation of the scours to occur is of great importance for the stability of the port structures. In this study, scour in front of a vertical wall was investigated experimentally. For this purpose, quartz sand with an average sieve diameter of d50= 0.24 mm and a specific mass of ρ= 2650 kg/m3 was laid on the bottom of the 3.2x2.0x1.0 m test tank. A propeller made of brass with a diameter of 0.06 m was used in the experiments. The propeller was placed in 4 different positions between its axis and the polycarbon-based vertical wall and operated at 3 different rotation speeds. Velocity measurements were obtained using an ADVP operating on the Acoustic Doppler principle. The findings on the effects of the distance between the vertical wall and the propeller axis and the propeller rotation speed on the scour mechanism were compared with the studies in the literature.

Keywords:

Scour, Vertical Wall, Propeller Jet, Confined scour,

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Blaauw, H. G., and van de Kaa, E. J. (1978). “Erosion of bottom and sloping banks caused by the screw race of manoeuvring ships.” Delft Hydraulics Laboratory, Delft, Netherlands, 1–12.
Cui, Y., Lam, W. H., Zhang, T., Sun, C., Robinson, D., & Hamill, G. (2019). Temporal model for ship twin-propeller jet induced sandbed scour. Journal of Marine Science and Engineering, 7(10), 339.
Cui, Y., Lam, W. H., Ong, Z. C., Ling, L., Siow, C. L., Robinson, D., & Hamill, G. (2020). Experimental Scours by Impinging Twin-Propeller Jets at Quay Wall. Journal of Marine Science and Engineering, 8(11), 872.
Fuehrer, M., Römisch, K., (1977). Propeller jet erosion and stability criteria for bottom protection of various constructions. In: Proceedings of P.I.A.N.C, Bulletin No.58.
Hamill, G. A. (1987). “Characteristics of the screw wash of a manoeuvring ship and the resulting bed scour,” Ph.D. thesis, Queen’s University of Belfast, 1987.
Hamill, G. A., Johnston, H. T. ve Stewart, D. P., (1999). “Propeller Wash Scour Near Quay Walls”, Journal of Waterway, Port, Coastal and Ocean Engineering, 125(4):15616, 1999.
Hong, J. H., Chiew, Y. M., & Cheng, N. S. (2013). Scour caused by a propeller jet. Journal of Hydraulic Engineering, 139(9), 1003-1012.
Llull, T., Mujal-Colilles, A., & Gironella, X. (2021). Twin propeller time-dependent scouring processes. Physical experiments. Ocean Engineering, 236, 109461.
P.I.A.N.C, (2015). The World Association for Waterborne Transport Infrastructure, “Guidelines for Protecting Berthing Structures from Scour Caused by Ships”. Report No.180, Belgium.
Römisch K., (1975). Der propellerstrahl als erodierendes element bei anund ablegenamovem von schiffen, Seewirtschaft Berlin, Vol.7, Part 7.
Sarker, A., Flow Measurement Around Scoured Bridge Piers Using Acoustic-Doppler Velocimeter (ADV), Flow Measurement and Instrumentation, 9, 217-227, 1998.
Tan, R. İ., & Yüksel, Y. (2018). Seabed scour induced by a propeller jet. Ocean Engineering, 160, 132-142.
Verhey, H. J. (1983). “The stability of bottom and banks subjected to the velocities in the propeller jet behind ships.” Delft Hydraulics Laboratory, Netherlands.
Wei, M., Chiew, Y. M., & Cheng, N. S. (2020). Recent advances in understanding propeller jet flow and its impact on scour. Physics of Fluids, 32(10), 101303.
Yuksel, Y., Tan, R. I., & Celikoglu, Y. (2019). Determining propeller scour near a quay wall. Ocean Engineering, 188, 106331.