IJE TRANSACTIONS A: Basics Vol. 32, No. 4 (April 2019) 602-607    Article in Press

PDF URL: http://www.ije.ir/Vol32/No4/A/19-3059.pdf  
downloaded Downloaded: 28   viewed Viewed: 298

H. Nourghassemi, H. R. Taghva, D. Molyneux and H. Ghassemi
( Received: May 03, 2018 – Accepted: March 07, 2019 )

Abstract    One of the most efficient methods of reducing drag on planing craft is the use of transverse step on the bottom of a hull. Applying steps on the hull reduces the contact area with water and as a result, it reduces drag of the craft. Planing craft are able to have one or two transverse steps. In this paper, numerical hydrodynamic performance of the stepped planing craft and its step height effect is investigated by making use of finite volume method (FVM). The Reynolds-Averaged Navier-Stokes (RANS) equations are coupled with the standard k- ε turbulence model and volume of fluid equations are solved to simulate transient turbulent free surface flow surrounding the hull by ANSYS-CFX. In order to predict the motion of the craft, equations of two degrees of freedom for rigid body are coupled with governing equations of fluid flow. In order to validate the numerical model presented in this paper, the obtained numerical results are compared with the available experimental data. The numerical results obtained for drag, dynamic trim, rising of center of mass and the pressure distribution on the body at different speeds and different heights of the steps are presented and discussed.


Keywords    Stepped Planing Craft; Transverse Step Height; Pressure Distribution; Lift and Drag



یکی از روشهای موثرو کارآمد برای کاهش درگ در شناورهای اسکی استفاده از پله های عرضی در کف شناور است. استفاده از پله باعث کاهش سطح خیس شده بدنه و در نتیجه موجب کاهش درگ می شود. شناورهای اسکی می توانند یک یا دو پله عرضی داشته باشند. در این مقاله با روش عددی عمکرد هیدرودینامیکی شناور اسکی پله دار و تاثیرارتفاع پله با روش حجم محدود مورد بررسی قرار گرفته است. معادلات ناویر استوکس به روش میانگین گیری رینولدز با مدل آشفتگی استاندارد k- ε برای شبیه سازی جریانهای سطح آزاد در اطراف بدنه شناور به کمک نرم افزار انسیس CFX حل شده است. بمنظور پیشگویی حرکت شناور، معادلات حرکت دو درجه آزادی با معادلات حاکم کوپل شده اند. جهت معتبرسازی، محاسبات نتایج عددی بدست آمده با نتایج تجربی مقایسه شده است. نتایج عددی بدست آمده شامل درگ، تریم دینامیکی، بالا امدن مرکز جرم، توزیع فشار روی بدنه در سرعتهای مختلف و در چند ارتفاع پله ارائه و بحث شده است.


1. Savitsky, D., "Hydrodynamic design of planing hulls", Marine Technology,  Vol. 1, No. 1, (1964).
2. Savitsky, D., DeLorme, M.F. and Datla, R., "Inclusion of whisker spray drag in performance prediction method for high-speed planing hulls", Marine Technology,  Vol. 44, No. 1, (2007), 35-56.
3. Brizzolara, S. and Serra, F., "Accuracy of cfd codes in the prediction of planing surfaces hydrodynamic characteristics", in 2nd International Conference on Marine Research and Transportation., (2007), 147-159.
4. Ghassemi, H. and Ghiasi, M., "A combined method for the hydrodynamic characteristics of planing crafts", Ocean Engineering,  Vol. 35, No. 3-4, (2008), 310-322.
5. Hassan, G. and Su, Y.-m., "Determining the hydrodynamic forces on a planing hull in steady motion", Journal of Marine Science and Application,  Vol. 7, No. 3, (2008), 147-156.
6. KOHANSAL, A., GHASSEMI, H. and GHIASI, M., "Hydrodynamic characteristics of high speed planing hulls, including trim effects", Turkish Journal of Engineering and Environmental Sciences,  Vol. 34, No. 3, (2011), 155-170.
7. Kohansal, A.R. and Ghassemi, H., "A numerical modeling of hydrodynamic characteristics of various planing hull forms", Ocean Engineering,  Vol. 37, No. 5-6, (2010), 498-510.
8. Akkerman, I., Dunaway, J., Kvandal, J., Spinks, J. and Bazilevs, Y., "Toward free-surface modeling of planing vessels: Simulation of the fridsma hull using ale-vms", Computational Mechanics,  Vol. 50, No. 6, (2012), 719-727.
9. Su, Y., Chen, Q., Shen, H. and Lu, W., "Numerical simulation of a planing vessel at high speed", Journal of Marine Science and Application,  Vol. 11, No. 2, (2012), 178-183.
10. Ghassabzadeh, M. and Ghassemi, H., "Determining of the hydrodynamic forces on the multi-hull tunnel vessel in steady motion", Journal of the Brazilian Society of Mechanical Sciences and Engineering,  Vol. 36, No. 4, (2014), 697-708.
11. Bakhtiari, M., Veysi, S. and Ghassemi, H., "Numerical modeling of the stepped planing hull in calm water", International Journal of Engineering-Transactions B: Applications,  Vol. 29, No. 2, (2016), 236-245.
12. Taunton, D., Hudson, D. and Shenoi, R., "Characteristics of a series of high speed hard chine planing hulls-part 1: Performance in calm water", International Journal of Small Craft Technology,  Vol. 152, (2010), 55-75.
13. Matveev, K.I., "Three-dimensional wave patterns in long air cavities on a horizontal plane", Ocean Engineering,  Vol. 34, No. 13, (2007), 1882-1891.
14. Svahn, D., "Performance prediction of hulls with transverse steps", A Report of Masters Thesis, The Royal Institute of Technology, KTH, Centre for Naval Architecture,  (2009).
15. Savitsky, D. and Morabito, M., "Surface wave contours associated with the forebody wake of stepped planing hulls", Marine Technology,  Vol. 47, No. 1, (2010), 1-16.
16. Matveev, K.I., "Two-dimensional modeling of stepped planing hulls with open and pressurized air cavities", International Journal of Naval Architecture and Ocean Engineering,  Vol. 4, No. 2, (2012), 162-171.
17. Garland, W.R. and Maki, K.J., "A numerical study of a two-dimensional stepped planing surface", Journal of Ship Production and Design,  Vol. 28, No. 2, (2012), 60-72.
18. Lee, E.J., "Advancements of stepped planing hulls", Virginia Tech,  (2014), 
19. Veysi, S.T.G., Bakhtiari, M., Ghassemi, H. and Ghiasi, M., "Toward numerical modeling of the stepped and non-stepped planing hull", Journal of the Brazilian Society of Mechanical Sciences and Engineering,  Vol. 37, No. 6, (2015), 1635-1645.
20. Nourghasemi, H., Bakhtiari, M. and Ghassemi, H., "Numerical study of step forward swept angle effects on the hydrodynamic performance of a planing hull", Zeszyty Naukowe Akademii Morskiej w Szczecinie,  (2017).
21. Nourghassemi, H., Ghassemi, H. and Taghva, H., "Numerical hydrodynamic results of the two stepped planing hull", American Journal of Mechanical Engineering,  Vol. 6, No. 3, (2018), 93-97.
22. Doustdar, M.M. and Kazemi, H., "Effects of fixed and dynamic mesh methods on simulation of stepped planing craft", Journal of Ocean Engineering and Science,  Vol. 4, No. 1, (2019), 33-48.
23. Lee, E., Pavkov, M. and McCue-Weil, L., "The systematic variation of step configuration and displacement for a double-step planing craft", Journal of Ship Production and Design,  Vol. 30, No. 2, (2014), 89-97. 

Download PDF 

International Journal of Engineering
E-mail: office@ije.ir
Web Site: http://www.ije.ir