Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

SPH Method for Impact Load of Water Spray Generated by the Landing Gear
Xiangshan Guan1, Ruosi Zha1, Decheng Wan2*2

1
School of Ocean Engineering and Technology, Sun Yat-Sen University, Zhuhai, Guangdong, China
Computational Marine Hydrodynamic Lab (CMHL), School of Naval Architecture, Ocean and Civil Engineering,Shanghai Jiao Tong University, Shanghai, China*Corresponding author

Among the effects of tire water spray, the impact of water spray on
aircraft structures cannot be ignored. High-speed droplets hit the aircraft
fuselage, wind speed ducts, engine blades and other critical locations,which may adversely affect aircraft safety and performance. Therefore,
simulating the spray patterns and calculating the impact load is an
important part of the numerical simulation of tire water spray. There aremany numerical studies related to tire water spray. In 1998, ESDU
proposed an engineering method to calculate the patterns of the sidespray according to a large number of test results. This method calculated
and described the parameters of side spray patterns, such as spray height,
sputter angle, and so on, according to the basic parameters such as tireparameters, depth of water accumulation, aircraft speed, and so on. In
2013, the CR-SPRAY method using the Monte Carlo method wasproposed by Gooden J H M. According to the initial patterns of tire sprayobtained by the ESDU method, the particle trajectory algorithm was used
to calculate the complete splashing trajectory. Liu et al. used the SPH
method to simulate the tire spray and simulated the splashing trajectoryin the discrete phase model method. They obtained the water spraypatterns of the nose gear, which were in good agreement with the test
results of ARJ21(Zhao K, Liu P Q, Qu Q L, 2018). In the meantime, Xu
et al. studied the water spray of elastic large deformation tires by the SPH
method and studied the tire hydroplaning phenomenon (Xianpeng
ZHANG, Fei XU, Xuanqi REN, 2019). However, these studies mainly
focus on the spray patterns (Guan Xiangshan, Xu Fei, Hu Muqiu, 2021),
and relatively few calculations are performed for the impact load of tire
water spray. Because the computational domain of tire water spray ishuge, if the complete process of tire water spray is simulated throughout
and the impact load of spray is calculated, the calculation time will bevery long.

ABSTRACTIn this paper, the impact load of water spray under the influence of air iscalculated, and an efficient and accurate calculation method is proposed.
Firstly, the initial patterns of tire water spray are simulated by the SPHFEM method in LS-DYNA, then the position and velocity informationof SPH particles is exported. Secondly, the SPH particles are regarded as
droplets, and the droplets load is calculated by the Monte Carlo method
according to the droplet impact load curve. The distribution of droplets
was modified according to the relationship between time and space.
Finally, the corrected impact load of water spray is obtained. The
calculated values are in good agreement with the measured values
obtained by the tire drop experiment, which proves the validity of themethod.

KEYWORDS: SPH method, impact load, tire spray, tire drop
experiment, Monte Carlo method

INTRODUCTION
Although the take-off and landing stages are short, they are the mostaccident-prone stages. When an aircraft passes through a wet runway, thetire water spray may enter the engine and affect the operation of theengine, and the water spray may also impact the aircraft fuselage andcause structural damage (Van Es G W H, Roelen A L C, Kruijsen E A C,
1998). To ensure the safety of aircraft, the FAA (Federal Aviation
Administration) had issued regulation AC-91-6A, which establishes
flight guidelines for slippery, waterlogged or contaminated runways.

Although it is difficult to use the SPH method to simulate the complete
process of tire spray, the SPH method can be used to obtain the initialpatterns of the tire spray accurately. SPH method is a meshless method.
The meshless method obtains accurate and stable numerical solutions
using a series of arbitrarily distributed nodes (or particles) to solve
integral equations or partial differential equations (PDEs) with different
boundary conditions. These nodes (or particles) do not require meshconnections, which can easily solve the large deformation, moving
interface and free surface problems encountered during numericalsimulation. The SPH method could avoid the precision damage caused

Therefore, the wet runway flight test is an essential process for civil
aircraft to obtain airworthiness certification, but it is expensive toconduct frequent flight tests of the whole aircraft. With the increasing
computing power of the computer, the water body can be refinedcontinuously. As a result, the calculation results of spray patterns andwater distribution can be more accurate, providing a reference for flighttests or even replacing some tests in the early stage. The numericalmethod effectively shortens the time to obtain airworthiness certificationand save test cost.

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