This paper provides, for the first time, a physical explanation of the dynamic fluid–structure stability response of an unconventional aircraft configuration called PrandtlPlane, which has been recently acknowledged as a possible candidate to foster the ambition of a greener aviation. As observed in previous literature efforts on this configuration, flutter onset is significantly different when considering

This research is devoted to understanding the physical mechanism of cavitation erosion in liquid flows at the fundamental scale of cavitation bubble collapse. Cavitation bubbles form in a liquid when the pressure of the liquid decreases locally below the saturated vapor pressure pvsat. The bubbles grow due to low ambient pressure and collapse when the surrounding liquid pressure increases again above

Accurate wall-shear stress (WSS) in-vitro measurements within complex geometries such as the human aortic arch under pulsatile flow are still difficult to achieve, meanwhile such data are important for classifying impacts of prosthetic valves on aortic walls. Micro-cantilever beams can serve to sense the WSS in such flows for applications in in-vitro flow tester. However, within pulsatile flows and

Two vortex-induced vibration (VIV) events of the main girder of long-span bridges successively happened on the Yingwuzhou suspension bridge and Humen suspension bridge in China, 2020, and drew public attention. Especially for the Humen suspension bridge, the amplitude of VIV was so notable that the traffic was closed for 10 days. Generally, VIV is sensitive to the structural and ambient issues and

For a pair of elastically mounted circular cylinders in a tandem configuration, the downstream cylinder may experience the wake-induced vibration (WIV) due to the hydrodynamic excitation associated with the wake behind the upstream cylinder. In addition to WIV, the downstream cylinder may also be simultaneously subject to the vortex-induced vibration (VIV) due to the vortex shedding in its own wake

Natural gas pipeline aerial crossing (NGPAC), also called natural gas pipeline bridge, is an important structure for gas transmission pipelines crossing special areas that are not suitable for trenchless technologies. The typical types of large-scale NGPACs are suspension and cable-stayed pipeline bridges. During the pigging process, suspension and cable-stayed NGPACs prong to strong vibration and

To date, it has been shown that the vibration response of an elastically mounted sphere undergoing vortex-induced vibration (VIV) can be controlled by imposing rotary oscillations at frequencies close to the vibration frequency. Here, we demonstrate that rotary oscillations imposed at significantly higher frequencies can be used to directly influence shear-layer vortex shedding and consequently reduce

The objective of this paper is to investigate laminar-to-turbulent transition-induced vibration of a NACA66 hydrofoil section at 4°angle of attack and Re=450,000. Direct Numerical Simulation (DNS) is used to simulate the three-dimensional incompressible flow, and is coupled with an equation of motion for a rigid hydrofoil supported at the elastic axis by a torsional spring and damper. The coupled 1-DOF

Liquid steel storage tanks equipped with floating roofs are critical components of industrial facilities because they often store hazardous material. Major earthquakes have caused large vertical displacements of floating roofs. Consequently, roof failure and/or content loss has occurred, which has seriously endangered the surrounding environment and community. Therefore, research interest in this topic

The paper presents a 3D entirely Lagrangian meshfree solver for reproduction of fluid–structure interactions (FSI) corresponding to incompressible fluid flows and elastic structures. A projection-based particle method, namely, Moving Particle Semi-implicit (MPS), is coupled with a Hamiltonian particle-based structure model, referred to as Hamiltonian MPS (HMPS) structure model. The HMPS structure model

Two degree-of-freedom (2-DoF) flow-induced vibrations (FIV) of two rigidly coupled cylinders are numerically investigated at the Reynolds number of 3.6×106. Two-dimensional (2D) Unsteady Reynolds-Averaged Navier–Stokes (URANS) simulations are performed combined with the k−ω SST turbulence model. A low mass-damping system is considered with a mass ratio of 2 and a damping ratio of zero. The diameter

Freeplay-induced limit-cycle oscillations (LCOs) have been a subject of concern for decades This paper proposes a novel method named the dual quasi-harmonic balance (DQHB) method for obtaining quick estimations on LCO behaviors. Two quasi-harmonic motions based on eigenvalues of the underlying and overlying linear systems are constructed so that a three-domain LCO can be interpreted as a dynamic balance

The present work is devoted to providing a full version of theoretical model for three-dimensional (3D) oscillations of a cantilevered pipe conveying fluid under large deformation. The geometric nonlinearity of the pipe is exactly considered by using an exact expression for the curvature of the pipe centerline. By taking variation operations with translational displacements or bending angles as the

In the present study, a variable stiffness method (VSM) is revisited for aeroelastic computations with/without thermal effects. Unlike the traditional CFD/CSM coupling method (TM), which predicts aeroelastic responses by varying freestream conditions (e.g. freestream density, velocity), the freestream conditions in VSM can be fixed. The VSM is first verified theoretically and adopted to predict nonlinear

Marine fouling is a major concern in marine aquaculture industry. It changes the flow field around the cage, reduces water exchange across the nets and affects the current/wave-induced forces acting on the structure. The current/wave forces induced to marine-fouled planar net panels were studied by previous researchers. The current paper reports the results of a series of small-scale physical model

The effect of Reynolds number on curves of the transverse-only motion amplitude of a circular cylinder with the body mass m∗=0.935 and the damping ratio ζ=0.00502 in the turbulent flow range is investigated systematically using a two-dimensional in-house code developed based on lattice Boltzmann method. Large eddy simulation is chosen as the turbulence model to describe viscous, incompressible and

Scaled model tests are an important step during the research and development of wave energy converters (WECs). While such scaled model tests in physical wave tanks are prone to undesired scaling effects due to e.g. mechanical artefacts and/or fluid effects, numerical wave tanks (NWTs) provide excellent tools for the analysis of WECs across a range of scales, overcoming the limitations of the physical

This paper addresses the case of a cylinder array in axial flow at Reynolds numbers from 60000 to 110000. A comprehensive experimental and numerical study of the steady fluid forces arising from a geometrical perturbation in the array arrangement is carried out and compared with a semi-empirical model from the literature. The test rig consists of a 3x3 confined cylinder bundle with a pitch-to-diameter

The hydrodynamic interactions between two pitching foils arranged in a side-by-side configuration are investigated numerically for a broad parameter space. This includes a range of Reynolds numbers between 1000 and 12 000, Strouhal numbers between 0.25 and 0.5, separation distances between 0.5c and 2c, and phase differences between 0° and 180°. The propulsive performance of side-by-side foils are compared

The dynamics of slosh induced wave systems in shallow water tanks is analyzed for various excitation conditions. Shake table experiments have been systematically performed to understand the complex interaction of multi-wave system under harmonic excitation. From the experiments, it was observed that, for relatively large excitation amplitudes, the hydraulic jumps emanated around the resonance region

This paper presents direct numerical simulations (DNS) on unsteady turbulent flow in a vibrating low-pressure turbine blade cascade to predict the flutter instabilities and explores the effects of blade oscillations on the flow structure and flow separation point. The spectral/hp element method is employed for the three-dimensional simulations of the domain. This method enables capturing more details

Airfoil stall plays a central role in the design of safe and efficient lifting surfaces. We typically distinguish between static and dynamic stall based on the unsteady rate of change of an airfoil’s angle of attack. Despite the somewhat misleading denotation, the force and flow development of an airfoil undergoing static stall are highly unsteady and the boundary with dynamic stall is not clearly

Insects are excellent fliers because of their ability to generate precise wing kinematics and deform their wings for the sufficient production of unsteady aerodynamic forces. Most of the previous studies on the effects of wing kinematics on the aerodynamics have been limited to the use of rigid wings, and leaves the contribution of wing flexibility unknown. Here, an experiment was conducted to investigate

In the present work, an efficient Reduced-Order Model is developed for the prediction of motion-induced unsteady pressure distributions. The model is trained on the basis of synthetic data generated by full-order Computational Fluid Dynamics (CFD) simulations. The nonlinear identification task is to predict a snapshot representing the pressure distribution for the current time step based on respective

A hydroelastic model is developed for the problem of linear wave interaction with a submerged horizontal flexible porous structure in three-dimensions. The generalized expansion formulae with orthogonal mode-coupling relations are derived by expanding Fourier cosine series in a channel width. Using eigensolutions, various aspects of hydroelastic wave behaviour in a channel with a porous plate submerged

The axial vibration of the liquid-filled pipes can be represented with a four-equation fluid–structure interaction (FSI) model. When distributed friction was neglected, this model could be solved with an exact solution without computational grid, while the only weakness was the high time cost. A fast meshless solution (FMS) developed earlier used the time-line interpolation rather than the recursive

The time domain state space model for describing an aeroelastic system has usually been obtained by using rational function approximations to write unsteady aerodynamics in the time domain. This strategy has been employed by many researchers because the standard form of unsteady aerodynamics is typically computed in the reduced frequency domain with explicit or implied transcendental functions, which

The unsteady characteristics for the water-skipping problem of a spinning stone, including the cavity dynamics, velocity field distribution, deviation and hydrodynamics, are investigated numerically for the stone with different attack angles and spinning velocities. A three-dimensional numerical model with six degrees of freedom is established based on the large eddy simulation (LES) model and the

In this paper the numerical simulations of the flow around an elastically-mounted circular cylinder with one degree of freedom (1-DOF) with small damping parameter and small mass ratio are presented. The simulations are performed for subcritical Reynolds numbers (2.0⋅103

The effect of length and stiffness of an attached flexible foil on the flow field of a square cylinder is studied. The intermediate Reynolds numbers are considered in the study. For flow diagnosis, particle image velocimetry, constant temperature anemometry, and flow visualization techniques are used. The increase in the length of the foil modifies the Strouhal frequency and mean drag coefficient non-monotonically

Combined variable rotor speed and active blade twist helicopter technologies have the potential to reduce the environmental and acoustic impact of modern rotorcraft. This paper explores the aeroacoustics, environmental and ground noise impact of combined variable rotor speed and active blade twist helicopter rotors, optimized for simultaneous mitigation of source noise and NOx emissions. An integrated

The presented investigation is motivated by the need to uncover connections between underlying rotor fluid–structure interactions and vortex dynamics to fatigue performance and characterization of flexible rotor blades, their hub, and their supporting superstructure. Towards this effort, temporal stability characteristics of tip vortices shed from flexible rotor blades are investigated numerically

The system under consideration comprises a flexible pipe and a rigid outer tube; the pipe and tube are concentric and vertically cantilevered from their top ends in a large water-filled cylindrical tank. The space between the pipe and tube forms an annulus around the upper portion of the pipe. The working fluid is water. The fluid enters the annulus from its top end with flow velocity Uo and is discharged

This paper presents the development of a numerical model for violent hydrodynamics of free-surface flows interacting with flexible structures using the meshless smoothed particle hydrodynamics (SPH) method accelerated with a graphics processing unit (GPU). The present work implements a unified SPH framework to solve both the fluid and structural dynamics within the open-source SPH code DualSPHysics

Four data-driven low-order modeling approaches, Dynamic mode decomposition (DMD) and three other variations (optimal mode decomposition, total-least-squares DMD and high-order DMD), are used to capture the spatio-temporal evolution of fluid–structure interactions. These methods are applied to experimental data obtained in a flow over a flexible membrane wing and its elastic deformation. Spectral coherence

Based on a fully nonlinear time-domain higher-order boundary element method (HOBEM), the present paper investigates a semi-circular floating body entering obliquely into Stokes wave with air entrapment. In this model, a fifth-order analytical solution is used to simulate the Stokes wave as incident boundary condition. A long and thin jet layer is simulated and assumed to separate from wetted body surface

Experiments on oblique water entry of high-speed projectiles are performed to investigate cavity evolution and impact loads. The nose shape determines the cavity behavior and consequently affects the load characteristics. Each projectile used in the experiments has a truncated-cone head and a cylindrical body. The geometry of the truncated cone is defined by two dimensionless parameters. We adopt 40

Flexible thin manufactures (sheets) are used in numerous engineering applications. In their manufacturing processes, the sheets are subjected to a fluid flow, and external disturbances can induce vibrations. The vibrations cause severe damage to the sheets. Therefore, an in-depth understanding of the vibration characteristics and excitation mechanism of a sheet in a fluid flow is essential. In this

The peak loads experienced by aircraft of all scales will typically be during gusts, turbulence or extreme manoeuvres. Understanding the aerodynamic response to these transient disturbances is therefore crucial, particularly when Leading-Edge Vortices (LEVs) occur. This fundamental study investigates the aerodynamic response to a wide range of transient plunging motions. The peak loads exhibited a

The structural motion and unsteady aerodynamic loads of a pitching airfoil model that features an actuated trailing edge flap are determined experimentally using a single measurement and data processing system. This integrated approach provides an alternative to the coordinated use of multiple measurement systems for simultaneous position and flow field measurements in large-scale fluid–structure interaction

Transverse vortex-induced vibration (VIV) of a two-dimensional, elliptic cylinder with various aspect ratios and stiffness is studied. The cylinder is elastically mounted and heated, and the flow direction is aligned with the direction of the thermal-induced buoyancy force. The transverse VIV can be suppressed as the thermal control parameter, the Richardson number (Ri), increases. Complete suppression

The drag–thrusttransition and wake structures of a pitching foil undergoing asymmetric sinusoidal oscillation are numerically investigated for foil thickness-based Strouhal number StD = 0.1–0.3 and amplitude ratio AD = 0.5–2.0. The asymmetry in the oscillation is introduced by making one half-stroke (e.g. from the lower extreme to the upper extreme) faster than the other. The results reveal that the

The study of the free swimming of undulating bodies in an otherwise quiescent fluid has always encountered serious difficulties for several reasons. When considering the full system, given by the body and the unbounded surrounding fluid, the absence of external forces leads to a subtle interaction problem dominated, at least at steady state conditions, by the equilibrium of strictly related internal

Damping screens are often installed within a tuned liquid damper (TLD) to increase the energy dissipation beyond what the sloshing liquid alone can provide. Many numerical models exist to study the response of a TLD; however, there are often associated limitations on fluid depth or excitation amplitude. The smoothed particle hydrodynamics (SPH) method can capture the fully nonlinear TLD response without

This paper reports the numerical results of the flow-induced vibration (FIV) of a trapezoidal cylinder with base length ratio of 0.3 placed at various flow orientations. Three typical attack angles (θ) of 0° (shorter base facing flow), 90° and 180° are examined in the computations that carried out for a reduced velocity range of Ur=2–20 at a low Reynolds number of 150. The vortex-induced vibration

In order to better understand the mechanism of panel flutter at low supersonic speeds, and to study the viscous effect on flutter boundary and flutter type, a coupled computational fluid dynamics and computational structure dynamics (CFD/CSD) methodology has been adopted. Detailed modal stability analyses have been conducted through the higher-order dynamic mode decomposition (HODMD) method, which

The control performance of a streamwise-oriented dielectric barrier discharge (DBD) plasma actuator, a set of plasma streamwise vortex generators (PSVGs), and a hybrid actuator of the plasma actuator and PSVGs on the reduction in bluff body flow separation, vortex-induced vibration (VIV), and wake fluctuation is experimentally investigated. Experiments are conducted in a low-speed and low-turbulence

Researchers, through time, have been conducted a series of theoretical and experimental measures on the glaze icing phenomena, but very few literatures can be found to quantify the effects of cylinder oscillation on the evolution of water films and ice shapes, and further to characterize aerodynamic characteristics during the glaze ice accretion process. A preliminary study is carried out to demonstrate

The dynamics of a cantilevered plate driven by a train of tangentially-advecting vortex rings is significantly impacted by two temporal parameters, namely the Strouhal number and the frequency ratio. The former relates the vortex ring advection time-scale to the fundamental period of the vibrating structure, while the latter relates the vortex production frequency to the structural fundamental frequency

For smart system designs based on elastic structures, buckled elastic sheets where both edges are clamped have gained significant attention as they exhibit interesting dynamic behaviors, namely, snap-through motion. In this study, the critical conditions and post-equilibrium responses of tandem buckled sheets under unbounded uniform flow are investigated experimentally to understand the mutual interactions

To investigate the characteristics of vortex-induced vibration (VIV) of the twin-box girder, we carried out the VIV wind tunnel tests. The VIV of the twin-box girder occurs in the range of 4.680≤ Ur ≤6.113, with the maximum dimensionless VIV displacement RMS(y)/D=0.03308 at reduced velocity at Ur=5.949. It is interesting that the VIV suddenly disappears at Ur=6.276 at the loading stage, and the large

We present results from two-dimensional numerical simulations based on Immersed Boundary Method (IBM) of a cylinder in uniform fluid flow attached to bistable springs undergoing Vortex-Induced Vibrations (VIV). The elastic spring potential for the bistable springs, consisting of two potential wells, is completely defined by the spacing between the potential minima and the depth of the potential wells

Flow-induced vibration of a flexible cylinder placed in the wake of a stationary rigid cylinder is studied, experimentally. The flexible cylinder with an aspect ratio of 47 and a mass ratio of 120 was held fixed at both ends and placed horizontally in the wake of the upstream rigid cylinder in the test-section of a subsonic wind tunnel. The dynamic response of the cylinder is studied in both the streamwise

This paper extends the Eulerian–Lagrangian–Lagrangian (ELL) method to solve the three-dimensional (3D) fluid–structure interaction (FSI) problems with flexible thin solids. The continuum-based (CB) shell element is adopted to model the flexible, thin-shell structure that undergoes large deformation. Several benchmarking problems, including a 3D cylinder-beam problem, vertical beam bending, and flapping

Water entry of vertical cylindrical shell is a nonlinear and unsteady process that involves the coupling of multiphase flow. In this paper, a numerical simulation of the water entry of vertical cylindrical shell is carried out with an objective to examine the physical mechanism of flow characteristics due to the effect of inner diameter. The numerical results are validated and verified against the

Numerical simulations of flow-induced vibration of a near-wall circular cylinder with a small gap (e) to diameter (D) ratio (e∕D=0.1) at low Reynolds numbers 55≤Re≤200 (based on the incoming velocity U∞ and the diameter D) are performed using a finite volume method by means of modified OpenFOAM codes. As the cylinder is very close to the wall, remeshing is regularly applied during the body oscillation

In this paper, a numerical method is presented to study the dynamic behaviour of an isotropic rectangular plate subjected to aerodynamic loads induced by parallel supersonic airflow. A finite element model, based on bi-dimensional polynomial displacement functions and linear Piston theory, is used to study the dynamic behaviour of the solid plate coupled with aerodynamic loads. The developed approach

The present paper is dedicated to the development of a numerical model for the water impact of two-dimensional (2D) and axisymmetric bodies with imposed motion. The work is a first step towards the implementation of a 2D+t procedure to be used for the analysis of aircraft ditching. The problem is investigated under the assumptions of an inviscid and incompressible fluid, which is modeled by a potential