Jisheng Zhao

Jisheng Zhao
Monash University (Australia) · Department of Mechanical and Aerospace Engineering

PhD (Monash University)

About

65
Publications
12,878
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
796
Citations
Introduction
Dr Jisheng Zhao currently works in the Department of Mechanical and Aerospace Engineering, Monash University (Australia). Dr Zhao's research interests include fluid-structure interaction, flow-induced vibration of bluff bodies, control of flow-induced vibration, flow energy harvesting, vortex dynamics, wake transitions, aerodynamics of insect flights, aerodynamics of vehicles, aerodynamics of wind turbines, etc.
Additional affiliations
January 2015 - November 2017
Monash University (Australia)
Position
  • Research Associate

Publications

Publications (65)
Article
Full-text available
This study examines the influence of angle of attack of a square section cylinder on the cylinder’s flow-induced vibration, where the direction of the vibration is transverse to the oncoming flow. Our experiments, which traversed the velocity–angle of attack parameter space in considerable breadth and depth, show that a low-mass ratio body can unde...
Article
Full-text available
This study investigates the free transverse flow-induced vibration (FIV) of an elastically mounted low-mass-ratio square cylinder in a free stream, at three different incidence angles: 0, 20 and 45 degrees. This geometric setup presents a body with an angle of attack, sharp corners and some afterbody, and therefore is a generic body that can be use...
Article
Full-text available
This study investigates the nature of the dynamic response of an elastically mounted cylinder immersed in a free stream. A novel method is utilized, where the motion of the body during a free vibration experiment is accurately recorded, and then a second experiment is conducted where the cylinder is externally forced to follow this recorded traject...
Article
Full-text available
This study experimentally investigates the in-line flow-induced vibration (FIV) of an elastically mounted circular cylinder under forced axial rotation in a free stream. The present experiments characterise the structural vibration, fluid forces and wake structure of the fluid–structure system at a low mass ratio (the ratio of the total mass to the...
Article
Full-text available
While it has been known that an afterbody (i.e. the structural part of a bluff body downstream of the flow separation points) plays an important role affecting the wake characteristics and even may change the nature of the flow-induced vibration (FIV) of a structure, the question of whether an afterbody is essential for the occurrence of one partic...
Article
Full-text available
We present a decomposition of the streamwise fluid force for in-line vortex-induced vibration (VIV) to provide insight into how the wake drag acts as a driving force in fluid–structure interaction. This force decomposition is an extension of that proposed in the recent work of Konstantinidis et al. (J. Fluid Mech., vol. 907, 2021, p. A34), and is a...
Article
Two-dimensional numerical simulations of the flow around a NACA0012 profile at Reynolds number Re=5000 show that unsteady periodic flows reach different saturated states when increasing or decreasing the angle of attack between 7∘ and 8∘. Within this range, the lift signal shows co-existing periodic states and period-doubling, as the wake undergoes...
Article
The flow field and scalar concentration behind a sand dune-inspired jet-in-crossflow were measured to quantify the characteristics of flow and scalar mixing. The velocity was resolved from particle image velocimetry measurements, and the time-resolved concentration was simultaneously captured by planar laser-induced fluorescence. During the experim...
Article
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 influen...
Conference Paper
Full-text available
At Re = 5000, both experiments and two-dimensional simulations of a NACA0012 airfoil wake show that, as the angle-of-attack is increased, there is a steep rise in lift beyond approximately 5° as vortex shedding begins to occur. Simulations show that the unsteady flow displays different frequencies in its saturated state between 7° and 8° , although...
Article
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∕...
Article
In this work, we investigate the dynamics of vortex-induced vibration of an elastically mounted cylinder with very low values of mass and damping. We use two methods to investigate this canonical problem: first we calculate the instantaneous phase between the cylinder motion and the fluid forcing; second we decompose the total hydrodynamic force in...
Article
Full-text available
Feedback control of flow-induced vibration of a sphere - Volume 889 - T. McQueen, J. Zhao, J. Sheridan, M. C. Thompson
Article
The problem of vehicle window dewing not only affects the occupants’ comfort, but also interferes with the driver's sight and potentially threatens the safety of driving as well as electronic equipment in the vehicle. Therefore, analyzing the condensation process inside the cabin is of great practical concern to improve driving comfort and safety....
Article
Full-text available
Flow-induced vibrations of a pitching and plunging airfoil
Article
Full-text available
Flapping wings of insects can follow various complex-motion waveforms, influencing the flow structures over a wing and consequently the aerodynamic performance. However, most studies of insect-wing models incorporate either simple harmonic or robofly-like motion waveforms. The effects of other waveforms appear to be under-explored. Motivated by thi...
Article
The wing aspect ratio (AR), that is, the ratio of the wingspan to the mean wing chord, is the most important geometrical parameter describing an insect wing. While studies have shown that a change in AR affects the flow structure as well as the aerodynamic force components on wings, the reasons behind the wide variety of aspect ratios observed in n...
Conference Paper
A study has been conducted to investigate the effect of angle of attack (α) on the hydrodynamic performance and wake structure of a static NACA0012 hydrofoil in a free-stream flow at low Reynolds number (Re). The investigation employed water-channel experiments and in-house numerical simulations (based on an immersed interface method) over the angl...
Article
Full-text available
In the context of flow-induced vibration, the component of the hydrodynamic coefficient in-phase with the velocity of an oscillating body, Cv, can be termed “positive excitation” or “negative damping” if Cv > 0. While this empirical approach is of long standing in the literature it does not account for distinct physical mechanisms that can be assoc...
Article
This study experimentally investigates the transverse flow-induced vibration (FIV) of an elastically mounted cube at three different incidence angles of α=0∘, 20∘ and 45∘, corresponding to two centreplane mirror-symmetric cases and one asymmetric case. The FIV response is characterised by analysing the vibration amplitude and frequency responses, t...
Conference Paper
Full-text available
The flow over an insect wing can be highly influenced by the wing aspect ratio (A), affecting the aerodynamic forces. Previous studies present apparently contradictory effects of A, creating a challenge in selecting the optimum A in the design of insect-inspired micro air vehicles. Some recent studies indicate that the A-effects are coupled with th...
Preprint
Full-text available
We investigate vortex-induced vibration of an elastically mounted cylinder with very low mass and damping using a decomposition of the total fluid force into drag and lift components that act along and normal to, respectively, the instantaneous effective angle of attack as the cylinder oscillates transversely to the free stream. Initially, we consi...
Article
Full-text available
Wing shape is an important factor affecting the aerodynamic performance of wings of monocopters and flapping-wing micro air vehicles. Here, an evolutionary structural optimisation method is adapted to optimise wing shape to enhance the lift force due to aerodynamic pressure on the wing surfaces. The pressure distribution is observed to vary with th...
Article
This study reports on an experimental investigation of the effect of mass ratio on the transverse flow-induced vibration (FIV) response of an elastically mounted square cylinder placed at three different incidence angles: two symmetric with respect to the centreplane, α=0° and 45°; and one asymmetric at 20°. These three angles display different dom...
Article
A new class of vibrations has been discovered where the vibrations are induced by forced sinusoidal rotary oscillation of a sphere. They have been termed Rotary-Induced Vibrations (RIV). RIV is observed only for selected forcing parameters, where the vibrations are locked to the forcing frequency. For these cases, the vibration amplitude increases...
Conference Paper
Full-text available
Rotating bluff bodies are known to experience a side force due to a well-known phenomenon called the Mag-nus effect. The Magnus effect is evident in many sports (cricket, soccer, baseball, and football), where spinning balls are known to change their trajectories dramatically. In this study, we have experimentally investigated the effect of imposed...
Article
While the flow-induced vibration (FIV) of a circular cylinder has been characterised in considerable detail, the FIV of elliptical cylinders has not received similar attention. This study investigates the dynamic response of elastically-mounted elliptical cylinders with various cross-sectional aspect ratios (or elliptical ratios) in a free stream....
Article
This study reports an experimental investigation on the flow-induced vibration (FIV) of elastically mounted rectangular cylinders with high-side-ratio in free-stream flow. The side ratio (σ), defined as the ratio of the cross-flow side width (h) to the streamwise side width (b) of the cylinder, namely σ=h∕b, was varied from 2.0 to 5.0. The fluid–st...
Article
The individual and combined influences of aspect ratio ( $A$ ), Reynolds number ( $Re$ ) and Rossby number ( $Ro$ ) on the leading-edge vortex (LEV) of a rotating wing of insect-like planform are investigated numerically. A previous study from our group has determined the wingspan to be an appropriate length scale governing the large-scale LEV stru...
Article
This experimental study investigates the effect of imposed rotary oscillation on the flow-induced vibration of a sphere that is elastically mounted in the cross-flow direction, employing simultaneous displacement, force and vorticity measurements. The response is studied over a wide range of forcing parameters, including the frequency ratio $f_{R}$...
Article
Full-text available
This study investigates the effect of angle of attack on flow-induced vibrations (FIVs) of sharp-edged rectangular cylinders. In particular, the effect of the afterbody of a rectangular cross-section with low mass ratio and the side ratio ranging from 0.67 to 1.5 is analysed by changing the angle of attack with respect to the oncoming free-stream....
Article
Full-text available
The flow-induced vibration response of a square cross-sectional cylinder with low mass and damping ratio is analysed using continuous wavelet transforms (CWT) for three representative angles of attack of the cylinder to the incoming flow. The amplitude and frequency responses over a range of flow velocities map out multiple regimes (branches) of os...
Article
The effect of damping on vortex-induced vibration (VIV) of a circular cylinder with a fixed mass ratio ($m^* = 3.0$) was studied through water-channel experiments. An eddy-current-based damping mechanism was constructed to provide controlled and adjustable damping values. It consisted of a permanent magnet connected to the cylinder that moves paral...
Article
Full-text available
The present experimental investigation characterises the dynamic response and wake structure of a sinusoidally rotating circular cylinder with a low mass ratio (defined as the ratio of the total oscillating mass to the displaced fluid mass) undergoing cross-stream flow-induced vibration (FIV). The study covers a wide parameter space spanning the fo...
Article
Results are presented from an experimental investigation into the effects of proximity to a free surface on vortex-induced vibration (VIV) experienced by fully and semi-submerged spheres that are free to oscillate in the cross-flow direction. The VIV response is studied over a wide range of reduced velocities: $3\leqslant U^{\ast }\leqslant 20$ , c...
Article
Full-text available
Stable attachment of a leading-edge vortex (LEV) plays a key role in generating the high lift on rotating wings with a central body. The central body size can affect the LEV structure broadly in two ways. First, an overall change in the size changes the Reynolds number, which is known to have an influence on the LEV structure. Second, it may affect...
Poster
Full-text available
Discrepancies exist in the effects of aspect ratio on the lift coefficient (CL) of insect wings reported in past studies. CL is found to be affected by the aspect ratio, Reynolds number and Rossby number - studied over a large parameter space. The large scale vortex structure over a wing is found to scale with the wing span. The Reynolds number and...
Article
Vortex-induced vibration (VIV) of a sphere represents one of the most generic fundamental fluid–structure interaction problems. Since vortex-induced vibration can lead to structural failure, numerous studies have focused on understanding the underlying principles of VIV and its suppression. This paper reports on an experimental investigation of the...
Article
Full-text available
While flow-induced vibration of bluff bodies has been extensively studied over the last half-century, only limited attention has been given to flow-induced vibration of elastically mounted rotating cylinders. Since recent low-Reynolds-number numerical work suggests that rotation can enhance or suppress the natural oscillatory response, the former c...
Conference Paper
Full-text available
Time-resolved measurements of the fluid forces acting on a circular cylinder undergoing vortex-induced vibration were conducted using a two-component force balance simultaneously with the displacement of the cylinder. The measured forces were analyzed into a component acting along the instantaneous direction of the relative velocity between the osc...
Article
The structural response and energy extraction of a foil undergoing two-degree-of-freedom fully passive flapping motions in a two-dimensional flow are numerically investigated at Re=400. The simulations of the fluid–structure interaction were conducted using the Immersed Boundary Method (IB Method). In the parametric space of flow reduced velocity a...
Conference Paper
Full-text available
The stable attachment of a leading-edge vortex (LEV) is responsible for the high lift observed from insect wings. In experiments, we study the flow structure over a model wing mounted on a central body. The diameter of the central body and the change in Rossby number (Ro) due to placement of the wing root away from the centre can affect the flow st...
Article
In the vehicle industry, thermal balance experiments have been extensively conducted on engines to determine energy distribution from fuel to engine power. The temperature differences between the hot and cold sides of the vehicular heat exchanger are the key parameters used to calculate the heat quantity. However, in certain gas–liquid heat exchang...
Presentation
Full-text available
This study investigates experimentally the transverse vortex-induced vibration of an elastically mounted low-mass-ratio circular cylinder in a free stream. Here, the focus is on the upper response branch where the vibration is chaotic according to previous studies. Auto- and cross-power spectra of the transverse displacement and force were computed...
Conference Paper
This study investigates experimentally the transverse vortex-induced vibration of an elastically mounted low-mass-ratio circular cylinder in a free stream. Here, the focus is on the upper response branch where the vibration is chaotic according to previous studies. Auto-and cross-power spectra of the transverse displacement and force were computed...
Poster
Full-text available
Stable attachment of the Leading Edge Vortex (LEV) is a peculiar aspect of aerodynamics of flapping wings of insects providing much higher lift than that from the aircraft wings. Parameters such as wing aspect ratio (AR), Reynolds number (Re), advance ratio and wing flexibility play an important role in determining the stability of a LEV. In our pr...
Conference Paper
Stable attachment of the Leading Edge Vortex (LEV) is responsible for stable flight in insects. The LEV structure over a flapping insect wing is influenced by several geometrical and kinematic parameters. In our study, it is shown that a change in the wing Reynolds number (Re) affects the LEV structure. A comparison with previous numerical results...
Conference Paper
Full-text available
The present study aims at describing the evolution of the dynamical response observed for a rectangular section of side ratio (SR) 1.5 tested in a low mass ratio (m *) range. The transition between very low to higher m * regimes for these reference sections has not been documented yet in the reference literature. A wide experimental campaign was pe...
Conference Paper
Full-text available
The present study aims at describing the evolution of the dynamical response observed for a rectangular section of side ratio (SR) 1.5 tested in a low mass ratio (m *) range. The transition between very low to higher m * regimes for these reference sections has not been documented yet in the reference literature. A wide experimental campaign was pe...
Conference Paper
An experimental investigation has been carried out in a water channel on the transverse flow-induced vibration of a square cross-section cylinder at two different angles of incidence to the free-stream, α= 0◦(square) and 45◦(diamond). The oscillation amplitude and frequency response of the cylinder were measured over a range of reduced velocity, U∗...
Article
Full-text available
An experimental investigation has been carried out in a water channel on the transverse flow-induced vibration of a square cross-section cylinder at two different angles of incidence to the free-stream, α 0 H (square) and 45 H (diamond). The os-cillation amplitude and frequency response of the cylinder were measured over a range of reduced velocity...
Article
Vortex-induced vibration (VIV) occurs when vortex shedding from a body results in fluctuating forces that, in turn, cause the body to vibrate. This can result in undesired large-amplitude vibrations leading to structural damage or catastrophic failure. While much has been done on the VIV of a circular cylinder less has been done on other canonical...

Network

Cited By

Projects

Projects (3)
Project
The project aims at elucidating the complex dynamics encountered in vortex-induced vibration, which is one of the basic mechanisms of flow-induced vibration due to crossflow over bluff bodies.
Project
To study different geometrical and kinematic parameters that affect the insect wing aerodynamics.