Abstract
A one-way Fluid and Structure interaction method is introduced based on a lumped parameters
method and a Reynolds-averaged Navier-Stokes solver with automatic viscous mesh generation. The
lumped parameters method is numerically solved by fourth-order Runge-Kutta method. Unidirectional
coupling by hydrodynamic interpolation and transformation from flow field to cable dynamics. A
dimensional analysis is applied in this high Fluid and Structure Interaction (FSI) system. The Reynolds
effects and Strouhal effects are both fully discussed. A two scale ratios model is applied in scale effect
analysis. We found a similarity of hydrodynamic distribution and vortex shedding in scaled cable wake
under only given two-ratios. The upper bound Reynolds effect is also discussed.
Key Words
fluid structure interaction; lumped mass method; reynolds number; scale effect; strouhal
number; towed cable system
Address
Wang Zhibo and Huan Shuaiyu: School of ocean engineering, Jiangsu Ocean University, Lianyungang, Jiangsu, 222005, China
Abstract
Simultaneous localization and mapping (SLAM) is a critical capability for any autonomous
underwater vehicle (AUV) in various underwater applications, including infrastructure inspection and
seabed exploration. However, achieving robust and accurate state estimation in such environments remains a
significant hurdle. This is primarily attributable to the inherent scarcity of geometric features in the subsea
environment itself and the limited field of view (FoV) of imaging sonar used for feature acquisition. These
factors collectively elevate the probability of iterative closest point (ICP) degeneracy, a frequent challenge in
most SLAM solutions. To overcome this limitation, this study proposes a method that actively adjusts the
imaging sonar
Address
Geonwoo Park: Division of Advanced Nuclear Engineering, Pohang University of Science and Technology (POSTECH),
77 Cheongam-ro, Nam-gu, Pohang-si, Gyeongbuk 37673, Republic of Korea
Dongsub Kim, Bonchul Ku, Seungwon Ham and Son-Cheol Yu: Department of Convergence IT Engineering, Pohang University of Science and Technology (POSTECH),
77 Cheongam-ro, Nam-gu, Pohang-si, Gyeongbuk 37673, Republic of Korea
Sungduk Kim and Jinbeom Kim: Maritime RD Center, LIG Nex1, 333 Pangyo-ro, Bundang-gu, Seongnam-si,
Gyeonggi-do 13488, Republic of Korea
Abstract
The hydrodynamic variations around floating structures in the naval ship applications are crucial
to study its stability and hull optimization. The choice of the hull shape is capital to reduce the dispenses
associated with energy. We address one-way fluid–structure interaction for a rigid (fixed) hull under a fluid
dynamics model. Structural dynamics are not solved. The developed model is based on the coupling
between Reynolds Averaged Navier-Stokes (RANS) equations and a k −e turbulence model. This model
extends naturally several models available in the literature including classical RANS models (steady and
unsteady) and several RANS based models that neglect the turbulence phenomena (including transport and
diffusion). The coupled RANS-based model is implemented numerically using finite element methods. We
have chosen a two-dimensional ship hull 2D model to show how modelling can address turbulent flows
around fixed structure. The numerical results obtained are encouraging and can allow us to study their
optimization for the preliminary phase with a certain precision.
Key Words
finite element methods; RANS-based model; rigid ship hull; tests simulation
Address
Jules Cesar Ketchakou: Mechanic and Materials Laboratory (LGMM) of National Higher Polytechnic school of Douala,
University of Douala, P.O.BOX 2107, Douala, Cameroon
Dianorre Tokoue Ngatcha, Ekmon Mbangue and Severin Nguiya: Mechanic and Materials Laboratory (LGMM) of National Higher Polytechnic school of Douala,
University of Douala, P.O.BOX 2107, Douala, Cameroon
Achille Pandong: Department of Marine and Port Engineering, National Higher Polytechnic school of Douala,
University of Douala, P.O.BOX 2107, Douala, Cameroon;
National Advanced School of Maritime and Ocean Science and Technology of University of Ebolowa,
Kribi, Cameroon
Abstract
The geometry of the underlip in onshore oscillating water column (OWC) systems is a key determinant of their hydrodynamic performance, directly influencing the wave-structure interactions and energy conversion efficiency. Recent advances in experimental hydrodynamics have highlighted the potential of geometric optimization; however, the specific influence of underlip configurations remains underexplored in the context of high-fidelity computational modeling. This study addresses this gap by
performing a systematic evaluation of multiple underlip geometries using computational fluid dynamics
(CFD) simulations. The analysis revealed that subtle geometric modifications could yield substantial
performance gains. Notably, the circular underlip configuration achieved the highest improvement,
enhancing the efficiency by 9.1% under a takeoff damping variation of 0.0079. This improvement was
attributed to its capacity to suppress turbulent kinetic energy generation during wave impact, thereby
reducing energy dissipation. The results present a novel, cost-effective design optimization pathway that
requires minimal structural modification, contributing to the growing body of research on hydrodynamic
enhancement strategies for OWC-based wave energy converters.
Key Words
computational fluid dynamic; hydrodynamic; oscillating water column; underlip
geometry; wave conversion energy
Address
Muhammad A. Bramantya and Heru S.B. Rocharjo: Department of Mechanical and Industrial Engineering, Faculty of Engineering, Gadjah Mada University, Jl. Grafika 2, Yogyakarta 55281, Indonesia
Ayodya P. Tenggara and Rahmawan Budiarto: Department of Nuclear Engineering and Engineering Physics, Faculty of Engineering,
Gadjah Mada University, Jl. Grafika 2, Yogyakarta 55281, Indonesia
Abstract
In the present study, the extended standard complex variable method (ESCVM) was proposed as
a robust method for calculating the analysis of design sensitivities, including the first and second order. The
standard complex variables method (SCVM) uses only the imaginary step for sensitivity analysis. In contrast,
the presented method applies both the imaginary and the real part to enhance the effectiveness of the
procedure. To illustrate this, the ESCVM is employed for the transited laminar incompressible flow. The
Navier-Stokes equations are solved using finite element analysis and the developed SCVM was then applied
to them. It has been shown that the first order (FO) sensitivity analysis is less susceptible to variations in the
step size for both the standard and extended SCVM. However, it is evident that, unlike the SCVM, the
extended SCVM was less dependent on the step size in estimating the second-order sensitivity (SO). This
ability can be seen as an improvement in the efficiency and robustness of the extended standard method for
complex variables.
Key Words
extended complex variables method; finite element analysis; incompressible laminar
flows; Navier-Stokes equations; sensitivities analysis
Address
Mojtaba Sheikhi Azqandi: 1Mechanical Engineering Department, University of Birjand, Birjand, Iran
Mahdi Hassanzadeh: Department of Mechanical Engineering, Go.C., Islamic Azad University, Gorgan, Iran
