Advanced Method for Floatation Characteristics Determining of a Passenger Aircraft at the Emergency Ditching

Аuthors

Pogosyan M. A.^*, Kalutsky N. S.^**, Strelets D. Y.^***

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

*e-mail: kaf101@mai.ru
**e-mail: kalutskijns@mai.ru
***e-mail: maksmai33@gmail.com

Abstract

This article deals with aircraft water landing simulation problem. The air routes of modern aircrafts lie over the seas and oceans. In case of emergency, the aircraft has to perform water landing due to the absence of airfields. In this case, the aircraft structure should stay afloat for the time required for the passengers to leave the aircraft and enter the life rafts. 
During the past decades, many attempts were made to solve the problem of aircraft water landing (also referred to as ditching) mainly by implementing computational fluid dynamics (CFD) methods. Although CFD ensures a feasible solution, it requires excessive computational resources and is limited typically by the initial stage of water landing.
The authors of the presented article propose a numerical method, which is much cheaper in terms of computational resource consumption, and allows successfully modeling such an important stage of ditching as floating from the moment of an aircraft stoppage until the last passenger would leave the aircraft.
It is well known that the problem of floatability requires completely different approach rather than conventional CFD, FEM, SPH etc. numerical simulation methods. One of the main difficulties in the aircraft floatability simulation is that it is a durable process. Moreover, the physical phenomenon of the buoyancy force is being typically ignored in commercial solvers. 
In this article, the problem is being solved by the numerical optimization. The method proposed for this is called the ‘water balance optimization method’ (WBOM).
The software implementation of WBOM is being accomplished with the CATIA CAD system. The CAD system allows easily modeling the aircraft watertight sections and the water line position. Modern CADs incorporate their own application-programming interface (API), which allows the users to write their own programs automating the CAD operation. The proposed WBOM method was implemented successfully in the form of CATIA macros library.
Application of the WBOM ensures feasible economy of both time consumption and computational resources, as well as more accurate geometric results (the water line position) without the drawbacks associated with the mesh of elements.

Keywords:

civil aircraft certification, aircraft emergency ditching, optimization method for the aircraft floatability estimation, CATIA macros development

References

1. Qu Q, Hu M, Guo H, et al. Numerical Simulation of Water-Landing Performance of a Regional Aircraft. Journal of Aircraft. 2016;53(6):1680–1689. DOI: 10.2514/1.c033686
2.  Hughes K, Vignjevic R, Campbell J, et al. From Aerospace to Offshore: Bridging the Numerical Simulation Gaps—Simulation Advancements for Fluid Structure Interaction Problems. International Journal of Impact Engineering. 2013;61:48–63. DOI: 10.1016/j.ijimpeng.2013.05.001
3.  Karman T. The impact of seaplane floats during landing. NACA TN 321; 1929.
4.  Wagner H. Über Stoß- und Gleitvogänge an der Oberfläche von Flüssigkeiten. ZAMM Journal of applied mathematics and mechanics: Zeitschrift für angewandte Mathematik und Mechanik. 1932;12(4):193-215. DOI: 10.1002/zamm.19320120402
5.  Mayo WL. Analysis and modifications of theory for impact of seaplanes on water. NACA TR 810; 1945.
6.  Leigh BR. Using the momentum method to estimate aircraft ditching loads. Canadian Aeronautics and Space Journal. 1988;34:162-169. 
7.  Soding H. Berechnung der Flugzeugbewegung beim Notwassern. Thecnische Universitat Hamburg-Harburg Arbeitsbereiche Schiffbau, Bericht Nr. 602; 1999.
8.  Shigunov V. Berechnung der Flugzeugbewegung beim Notwassern. Thecnische Universitat Hamburg-Harburg, Arbeitsbereiche Schiffbau, Bericht Nr. 608; 2000.
9.  Bensh L, Shigunov V, Soding V. Pressure distribution during water impact for A340 and A3XX. CRAVHI Reference number EDB-1675/01, 2001.
10.  Mayo WL. Hydrodynamic impact of a system with a single elastic mode I. Theory and generalized solution with an application to an elastic airframe. NACA TR 1074; 1952.
11.  Miller RW, Merten KF. Hydrodynamic impact of a system with a single elastic mode II. Comparison of experimental force and response with theory. NACA TR 1075; 1952.
12.  Carcaterra A, Ciappi E. Hydrodynamic shock of elastic structures impacting on the water: theory and experiments. Journal of Sound and Vibration. 2004;271(1-2):411-439. DOI: 10.1016/j.jsv.2003.02.005
13.  Carcaterra A, Ciappi E. Prediction of the compressible stage slamming force on rigid and elastic systems impacting on the water surface. Non-linear Dynamics. 2000;21(2):193-220. DOI: 10.1023/A:1008338301185
14.  Faltinsen OM, Landrini M, Grecco M. Slamming in marine applications. Journal of Engineering Mathematics. 2004;48(3):187-217. DOI: 10.1023/B:engi.0000018188.68304.ae
15.  Wernsdorfer T, Keller K, Climent H. CN-235-300M Deepwater – Subscale Model, Ditching and Floatation Tests Plan. EADS-CASA NT-3-AA0-03005; 2003. Issue A. 
16.  Bensh L, Shigunov V, Beuck G, et al. Planned ditching simulation of a transport airplane. KRASH Users’ Seminar (07-10 January 2001; Phoenix/Arizona).
17.  Hua C, Fang C, Cheng J. Simulation of fluid-solid interaction on water ditching of an airplane by ALE method. Journal of Hydrodynamics, Ser. B. 2011;23(5):637–642. DOI: 10.1016/s1001-6058(10)60159-x
18.  Kozelkov A, Pogosyan MA, Strelets DY, et al. Application of mathematical modeling to solve the emergency water landing task in the interests of passenger aircraft certification. Aerospace Systems. 2021;4(1):75–89. DOI: 10.1007/s42401-020-00082-7
19.  Qu Q., Hu M., Guo H. et al. Study of Ditching Characteristics of Transport Aircraft by Global Moving Mesh Method. Journal of Aircraft. 2015;52(5):1550–1558. DOI: 10.2514/1.c032993
20.  Wang J, Lyle K. Simulating Space Capsule Water Landing with Explicit Finite Element Method. 48th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference (April 23-26, 2007; Honolulu, Hawaii). DOI: 10.2514/6.2007-1779
21.  Hammani I. Improvement of the SPH method for multiphase flows application to the emergency water landing of aircrafts: application to the emergency water landing of aircrafts. PhD thesis. L'école Centrale De Nantes; 2020. 145 p.
22.  Seddon CM, Moatamedi M. Review of water entry with applications to aerospace structures. International Journal of Impact Engineering. 2006;32(7):1045–1067. DOI: 10.1016/j.ijimpeng.2004.09.002
23.  Certification Specifications and Acceptable Means of Compliance for Large Aeroplanes (CS-25). Amendment 27. European Aviation Safety Agency; Brussels, Belgium; 2021. 1381 p.
24.  Brutyan MA, Ye H, Pavlenko OV. Numerical Study of the Mechanized Wing Profile Flowing-Around Specifics at Takeoff and Landing Modes in a Humid Air. Aerospace MAI Journal. 2024;31(3):7-13. (In Russ.). URL: https://vestnikmai.ru/publications.php?ID=182553
25.  Lysenkov AV, Orekhovskii VV, Kazhan EV, et al. A Technique for Aerodynamic Characteristics Computing and Profile Optimization for Air Propellers by Numerical Methods Based on Solving Reynolds Equations. Aerospace MAI Journal. 2024;31(3):23-33. (In Russ.).
26.  Lysenkov AV, Orekhovskii VV, Kazhan EV, et al. A Technique for Aerodynamic Characteristics Computing and Profile Optimization for Air Propellers by Numerical Methods Based on Solving Reynolds Equations. Aerospace MAI Journal. 2024;31(3):23-33. (In Russ.).
27.  Biran A, López-Pulido R. Ship Hydrostatics and Stability. 2nd ed. Butterworth-Heinemann (Elsevier); 2014. 414 p.
28.  Clark IC. The management of merchant ship stability, trim and strength. London: The Nautical Institute; 2010. 30111 p.
29.  Faber TE. Fluid Dynamics for Physicists. Cambridge University Press; 1995. 472 p.