High-performance flutter and post-flutter predictions are critical in the design of a vast range of nonlinear fluid-structural systems. However, these predictions are often unfeasible due to their high computational cost. Moreover, traditional methods for flutter and post-flutter predictions are model intrusive and limited to one varying parameter at a time. To address these shortcomings, this paper

The strip theory in hydrodynamics has been widely used for predicting complex vortex induced vibrations (VIV) behind bluff bodies, but the question of how accurate such predictions are has not been addressed adequately before. In order to corroborate the application of strip theory in VIV, we present a comparative study between free mono-frequency vibrations of a long flexible cylinder in both uniform

In this paper, we present a numerical study on the transverse flow-induced vibration (FIV) of an elastically mounted sphere in the vicinity of a free surface at subcritical Reynolds numbers. We assess the interaction dynamics and the vibration characteristics of fully submerged and piercing spheres that are free to vibrate in the transverse direction. We employ the recently developed three-dimensional

A 1D/3D Finite-Volume coupling is proposed for the Euler/Homogeneous Equilibrium Model equations. The present approach is based on the Finite-Volume framework making it possible to tackle general equations of state. A special attention is given to the conservation of mass, momentum and energy at the common 1D/3D interface. For fluid–structure interaction induced by fast-transient phenomena occurring

Based on a high-order implicit discontinuous Galerkin method, numerical simulations of a two-dimensional oscillating foil are performed to explore the origin of basic aspects of the flow such as the generation of interesting flow structures in the wake and the associated aerodynamic forces. Dimensional arguments suggest that the flow is characterized by non dimensional aerodynamic coefficients depending

Flow restricting orifices are important components for flow and pressure control in the oil, gas, and power generation industries. In many situations, the piping systems are operating under two-phase flow conditions. These orifices affect the redistribution of the two phases and induce vibrations in the piping structures. These vibrations often occur during a slug flow pattern and can severely affect

The paper is devoted to the study of hydrodynamics around long cantilever beams that perform flexural vibrations in first natural mode in a viscous incompressible fluid. The study is based on the numerical three-dimensional simulation of flows induced by vibrations. The fluid motion is described by the full non-stationary system of Navier–Stokes equations and the oscillation profile of the beam is

The compounding effects of panel flutter and oblique shock impingement are of great concern to the development of light-weight, high-speed vehicles. Shock-induced panel flutter response is investigated at M=2 and Re=120,000 using the Navier–Stokes equations closely coupled to the von-Kármán equations. A naturally occurring laminar inflow boundary layer and incident oblique shockwave are specified through

Vortex-induced vibration (VIV) of a flexible splitter plate attached to a square cylinder in laminar flow is investigated using fluid–structure interaction (FSI) simulation. The Reynolds number based on the edge length of the square cylinder (L) is fixed at Re = 100, while the structural parameters of the plate are set as ρp (density ratio) = 84.75, H/L (non-dimensional thickness) = 0.06, E (non-dimensional

A semi-analytical model of hydroelastic slamming for two-dimensional symmetric flexible bodies is presented in this paper. The hydrodynamic loads are computed using the analytical Modified Logvinovich Model (MLM) with account for elastic deflections of the body surface. The elastic deflections are described by the modal approach. The rigid and elastic motions of the body are computed at the same time

In this work, the fluid–structure interaction (FSI) problems have been studied by coupling the δ Smoothed Particle Hydrodynamics (δSPH) with the Smoothed Point Interpolation Method (SPIM), which is abbreviated as δSPH–SPIM coupled method. SPIM is used for structure dynamics owing to its good performance for large deformation analysis of solids. For the fluid solver, in order to further reduce the unphysical

Triple helical strakes have been proved to be highly effective in suppressing the vortex-induced vibration (VIV) of isolated riser. Nevertheless, when risers work in clusters, interference effect can give rise to more complicated flow-induced vibration (FIV) behaviors, which in turn will largely compromise the suppression efficiency of triple helical strakes. In this paper, an experimental investigation

The forewing and the hindwing of a dragonfly have different geometry that could be an evolutionary specialization for better aerodynamic performance via sophisticated wing pitch control. Under different extent of wing pitching by the wing root musculature, the fore- and hindwings could exhibit different shape deformation and aerodynamic characteristics as a result of passive shape deformation. We measured

The study of the dynamics of cantilevered thin flexible plates in reverse axial flow – also known as inverted flags – has become of significant interest, partly due to their energy harvesting potential. This paper presents fresh experimental results, aiming to enhance our understanding of the dynamics of inverted flags, particularly concerning stability and global dynamics sensitivity to various system

In this study, a practical approach to incorporate forward speed and hydro-elasticity effect in the frequency domain is developed. By utilizing the discrete-module-beam (DMB) method, flexible structures are partitioned into multiple rigid bodies that are connected by beam elements. The forward speed effect is taken into consideration in the multi-body hydrodynamics through the slender body and low

The main cables of suspension bridges show various cross-sectional shapes with the evolution of construction phases, and they may suffer from severe galloping at certain conditions. The aim of this work is to provide a convenient tool for predicting the critical condition and galloping amplitude of main cables, and to explore the in-depth driving mechanism of nonlinear galloping. Firstly, a numerical

Microcapsules are liquid droplets enclosed by a thin elastic membrane. Being suspended in an external fluid, they undergo large deformations when flowing. Their deformation can be solved numerically, but the resolution of the fluid–structure interactions (FSI) requires extremely long computation times. This is a major constraint for instance when identifying the membrane mechanical properties from

A geometrically-exact nonlinear theory is developed for pipes conveying fluid based on the total momentum of the fluid and pipe. The proposed model accounts for geometric and kinematic nonlinearities of the pipe and inertial coupling between the pipe and internal flow. The fully nonlinear differential governing equations are derived based on the momentum balance of pipe and fluid in floating non-inertial

The effect of structural nonlinearity on vortex-induced vibration of a rigid circular cylinder has been studied computationally for a fixed mass ratio of m∗=2.546 at Re=150. The arrangement of the springs and damper is similar to setup for the Standard Linear Solid (SLS) model used to model a viscoelastic material. One linear spring is in series with the damper and another nonlinear spring is parallel

Maritime structures operating out at sea experience large changes in wetted area because of free surface waves. Although these conditions are typical for maritime applications, a fundamental experiment that includes a structure in the air–water interface undergoing transitions from dry to wet and back does not appear to exist. This paper aims to fill that knowledge gap. We present an experiment in

In recent years, high-mode vortex-induced vibration (VIV) of stay cables has been observed in some cable-stayed bridges. It can cause undue stress and fatigue in the anchorages at the deck and/or pylons and in the cables themselves. In this study, experimental investigations were performed to characterise and control the high-mode VIV of stay cables by using horizontal- and inclined-rigid-stay-cable

In this paper, a new layout optimization technique is integrated with a statistical modal energy distribution analysis (SmEdA) model to obtain the optimal layout of a porous sound-absorbing material for noise control in mid-frequency vibro-acoustic systems. The considered optimization problem is minimizing the total energy of the internal acoustic cavity within the prescribed frequency range by reasonably

In this paper, the results of an experimental investigation of the normal impact of grooved spheres on a calm water surface are presented. Particular attention is given to describe the air cavity formation when the number of grooves and the impact velocity change. All experimental tests are conducted in a constant surrounding fluid Bond number, Capillary length using grooved spheres with constant diameter

We present a numerical study on the fluid–structure interaction of an incompressible laminar flow around a slender blunt-based body implementing a rear cavity of flexible plates. The study focuses on the use of this type of device to control the wake dynamics and the aerodynamic forces acting on the body, as well as to harvest energy from the flow. To that aim, the effects on the plates flow-induced

This paper presents an arrangement of sub-surface fixed horizontal plates as an alternative to single long plates and conventional breakwaters. Through experimental tests in a wave flume, their capability as coastal protection elements was evaluated varying the number of plates and their spacing, as well as the roughness of their crowns by means of three different flexible covers. Due to the spatial

Salt marshes are a common feature in coastal regions and have been noted for their ability to attenuate wave energy, providing an important first line of coastal defense. Marsh plants usually consist of multiple leaves distributed along a central stem. This paper constructed a model predicting wave force on a marsh plant by modeling the reconfiguration of both the leaves and stem in waves. The individual

An experimental and computational investigation was conducted to study the interaction between bubbles generated by an underwater explosive (UNDEX) and a nearby steel plate structure. The experiments were performed for different standoff distances to investigate the interaction between the gas bubble and the rigid structure. High-speed photography was utilized to capture the underwater explosive gas

A new model for the simulation of large motions of porous tensile structures and their interaction with the surrounding fluid is developed in this paper. The discrete structure is represented by several non-linear elastic bars and knots connecting up to four bars. An implicit system of equations is derived from the fundamental relations of dynamics, kinematics and material and solved using an improved

The analysis of violent sloshing is of great interest for European aeroplane manufacturers. It has been widely reported that aircraft fuel sloshing significantly damps wing vibrations, but the complexity of the fluid–structure phenomena still demands further research. The aim of this work is to define an experimental methodology to quantify the sloshing force acting on a vertical Single Degree Of Freedom

A particular behaviour is observed in the pitch-heave stall flutter of a NACA0012 airfoil at transitional chord-based Reynolds numbers during lock-in. When the air speeds is such that the airfoil oscillates at the pitch structural natural frequency, and the structural natural frequencies of the two motions are close and their ratio ω̄ (= fh∕fθ) is smaller than 1, the system exhibits a beating phenomenon

The paper performs simulation of a rectangular plate excited by turbulent channel flow at friction Reynolds numbers of 180 and 400. The fluid–structure interaction is assumed to be one-way coupled, i.e, the fluid affects the solid and not vice versa. We solve the incompressible Navier–Stokes equations using finite volume direct numerical simulation in the fluid domain. In the solid domain, we solve

Buoyancy modules are essential parts in the offshore oil and gas drilling and production practices. They provide weight compensation for the riser and help avoid excessive top tension exerted by the floating platform. However, the deployment of buoyancy modules with larger diameter than the bare riser may alter the geometric shape of the riser system and greatly influence the hydrodynamic performance

Three-dimensional numerical simulations are carried out to study the hydrodynamic performance and flow features of a bio-inspired underwater propulsor. The propulsor is constituted by a passive pitching panel. The leading edge of the panel is prescribed under a periodic heaving motion while the panel pitches passively due to the employing of a stiffness-lumped torsional spring at the leading edge.

This paper reports on an extensive numerical investigation of the effects of pivot location and mass ratio (m∗= solid/fluid mass) on flow-induced vibration (FIV) of a foil undergoing fully passive two-degree-of-freedom (2-DOF) plunging and pitching motion in a two-dimensional free-stream flow. Here, the normalised pivot location is defined by x=xp∕c, with c the foil length and xp the distance to the

This study is motivated by the non-linear behavior of the lift response of a pitching airfoil with a small amplitude and frequency where a linear behavior is expected. The validated γ−Reθ transition model coupled with k−ωSST (shear stress transport) turbulence model was utilized to solve the unsteady Reynolds-averaged Navier–Stokes (URANS) equations for a harmonically pitching NACA 0012 at Reynolds

The prediction of the penetration of three-dimensional (3D) shaped charge into steel plates is a challenging task. In this paper, the smoothed particle hydrodynamics (SPH) method is applied to simulate the jet formation generated by the shaped charge detonation and its damage to steel plates. The Jones–Wilkins–Lee (JWL) equation of state (EOS), Tillotson EOS, and elastic–perfectly plastic constitutive

High-performance aircraft often suffer from the consequences of tail buffeting at moderate subsonic Mach numbers and medium to high angles of attack. The impact of the aircraft’s highly unsteady flow field on the tails can result in significant structural fatigue and degraded handling qualities. Various methods have been developed to predict tail buffeting. Stochastic response methods are among frequently

The paper presents a wave basin experiment of a direct-driven point-absorber wave energy converter moving in six degrees of freedom. The goal of the work is to study the dynamics and energy absorption of the wave energy converter, and to verify under which conditions numerical models restricted to heave can capture the behaviour of a point-absorber moving in six degrees of freedom. Several regular

Current trends in the aircraft industry involve higher aspect-ratio wings made of lighter materials. These trends seek to reduce fuel emissions and increase flight efficiency by reducing drag to lift ratio and overall weight, respectively, of the aircraft. This results in reduced structural stiffness and coupling between the aeroelastic modes and flight dynamics. The flutter phenomenon is of particular

Landing gear doors on aircraft have experienced flutter during preliminary flight testing. While designs vary widely, landing gear doors are typically plate-like structures with a relatively rigid actuator attached to their inside surface. To better understand the aeroelasticity of landing gear doors, this study investigates the aeroelastic stability of an idealized model. The model consists of a hinged

When elastic spheres enter the water from air, the fluid–structure interaction becomes a complex problem characterized by large deformations. This paper focuses on the deformation behaviors of elastic spheres during water entry. Based on a strong coupling method, a numerical approach to the water entry of elastic spheres is established and validated using the experimental data. In addition to the descriptions

For a long-span suspension bridge, the suspender cables in the rear of tower often incur violent vibrations, owing to the wake effect of the upstream tower. In this study, an experimental investigation on the dynamic response of a suspender cable model was conducted, and an analytic model for the wake-induced vibration (WIV) of a suspender cable was proposed. The Xihoumen Bridge was selected as a prototype

In this paper, the sound generated by three-dimensional flexible flapping wings during hovering flight is numerically studied by using an immersed boundary method. The wing shape, prescribed motion of the wing leading edge, Reynolds number, wing-to-fluid mass ratio and wing flexibility are systematically examined. The numerical results show that these governing parameters have a significant influence

In this paper, a hybrid scheme, Fluid–Fluid–Elastic Structure (FFES) model was developed in the time domain to address the wave breaking impact on the structure. The model is developed based on the partitioned approach with different governing equations that describe various regions of the model domain. The fluid–fluid model denotes that two different fluid models were used to describe fluid in the

In this study, numerical methods are developed to simulate thermomechanical processes, taking into account both the fluid flows in the molten pool and the deformations of the solid parts. The methods are based on a new strategy of solid/fluid coupling. They allow to simulate the formation of the molten pool by taking into account the fluid flows through both effects of the surface tension (“curvature

The vortex induced vibration (VIV) mitigation on a circular cylinder with low mass ratio (i.e. the ratio of structural to displaced fluid mass) parameter and moderate Reynolds numbers through a nonlinear energy sink (NES) is investigated numerically as basis for applications on dynamics of spar platform, marine tunnel or risers used in the ocean engineering industry. The Reynolds-Averaged-Navier–Stokes

This paper presents the numerical study on the flight behaviour of spherical compact debris in a tornado-like wind field. The tornado-like vortex corresponding to a swirl ratio of 0.7 was generated using Large-eddy Simulation and the trajectories of 2250 individual debris particles placed in the flow were computed using Lagrangian-particle tracking. The debris corresponded to five groups (A, B1, B2

This paper studies the presence of the bistable flow activity around inclined cable models. It presents results from wind tunnel test on static original High-Density Polyethylene cable covers in a range of Reynolds numbers from the subcritical to the critical regime, inclined at angles of 90°(vertical), 60°and 45°. It has already been shown that, in the critical regime, turbulent transition in the

This paper presents a parametric study on a forced pitching hydrofoil. The non-dimensional frequency (Strouhal number, Std) and amplitude ratio (A∗) of the hydrofoil pitching are varied as 0.21 ≤ Std ≤ 0.33 and 0.55 ≤ A∗ ≤ 0.8, respectively. The numerical solution of the problem is obtained using unsteady Navier–Stokes equations. Coefficients of thrust, power, and efficiency of the hydrofoil are calculated

When a solid sphere exits water at a given velocity, the liquid column is pulled out of a liquid reservoir. The present study focuses on the dynamic deformation of the liquid column and on the identification of the liquid column regime on the Weber number and dimensionless time (We-t*) map. The three-dimensional model of water exit has been established on the basis of the lattice Boltzmann method.

The response of a NACA0012 airfoil impacted by vortical gusts is investigated performing Direct Numerical Simulations of the two-dimensional incompressible flow. Taylor vortices of different diameter and intensity located at different vertical separations with respect to the airfoil are deployed in the free stream. These vortices, which are characterized by its compact distribution of vorticity, are

Fall of open tori horizontally dropped in quiescent water is experimentally investigated. The fall is controlled by the Galileo number, the torus aspect ratio and the solid to fluid density ratio. The dependence of the descent velocity and of the drag coefficient on the control parameters is first analyzed. As the control parameters are varied, vertical translation, zigzagging and spiraling descent

A study is performed numerically to understand the effect of incident turbulence intensity Tu (0%–10%) on flow-induced vibration of an isolated elastic cylinder subjected to an axial tubular flow. The cylinder fix-supported at both ends is free to vibrate laterally. Large eddy simulation and the two-way coupled CFD-CSM calculation are employed to capture the characteristics of turbulent flow and fluid–structure

The generalized aerodynamic force (GAF) matrix is derived for the Unsteady Vortex Lattice Method (UVLM) without the assumption of out-of-plane dynamics. As a result, the approach naturally includes in-plane motion and forces unlike the doublet lattice method (DLM). The derived UVLM GAF is therefore applicable to industry-standard techniques for aeroelastic stability analyses, such as the p–k method

As is well known, gust responses of an elastic aircraft can be predicted by both time-domain and frequency-domain methods. The frequency-domain method can produce accurate predictions as long as the obtained aerodynamic data in frequency-domain is accurate. The time-domain method might involve the problem of degraded accuracy due to the modeling errors resulting from the rational function approximation

Complete analytical solution for the normally incident water wave scattering by a porous flexible vertical elastic plate or tensioned membrane is found. The physical problem in a half-plane is reduced to a couple of equivalent quarter-plane problems by allowing incident waves from either direction of the structure. In the same way, quarter-plane boundary value problems are posed for solid wave potentials

The present work is an experimental study of two oscillating rigid plates placed in side-by-side configuration, hinged at their leading edges, subjected to low subsonic flow. This problem is investigated using smoke-wire flow visualization, hot-wire anemometry, and time resolved particle image velocimetry. It is found that beyond a critical Reynolds number, the plates set into oscillatory motion. This

This paper analyzes the influence of turbulence on a wake-oscillator model. Turbulence is introduced by randomizing the model proposed by Facchinetti et al. under the quasi-steady assumption. A multiple scale analysis of the deterministic model shows that the response is governed by a dimensionless group D, expressed as a function of the amplitudes of the forcing terms in the two governing equations