Outputs (38)

On the asymmetric vortex evolution in the near wake behind polygonal cylinders in an incident flow (2024)
Journal Article
Cheng, H., Masoudi, E., Liu, Y., & Gan, L. (in press). On the asymmetric vortex evolution in the near wake behind polygonal cylinders in an incident flow. Ocean Engineering,

Asymmetric evolution of coherent vortices behind polygonal cylinders in an incident flow is studied using Proper Orthogonal Decomposition (POD) based phase averaging analysis. Flow around polygonal cylinders of side number $N\in[5,8]$ at Reynolds num... Read More about On the asymmetric vortex evolution in the near wake behind polygonal cylinders in an incident flow.

A Polynomial Model with Line-of-Sight Constraints for Lagrangian Particle Tracking Under Interface Refraction (2024)
Journal Article
Zeng, X., Qu, H., He, C., Liu, Y., & Gan, L. (2024). A Polynomial Model with Line-of-Sight Constraints for Lagrangian Particle Tracking Under Interface Refraction. Measurement Science and Technology, 35(6), Article 066011. https://doi.org/10.1088/1361-6501/ad34ec

This paper introduces an improvement of the "Shake-The-Box (STB)" (Schanz, Gesemann, and Schröder, Exp. Fluids 57.5, 2016) technique using the polynomial calibration model and the line-of-sight constraints (LOSC) to overcome the refractive interface... Read More about A Polynomial Model with Line-of-Sight Constraints for Lagrangian Particle Tracking Under Interface Refraction.

Formation and evolution of vortex rings with weak to moderate swirl (2023)
Journal Article
Ortega Chavez, R., Gan, L., & Gaskell, P. (2023). Formation and evolution of vortex rings with weak to moderate swirl. Journal of Fluid Mechanics, 967, Article A16

The formation of swirling vortex rings and their early time evolution, resulting from the controlled discharge of an incompressible, Newtonian fluid into a stationary equivalent fluid bulk, is explored for weak to moderate swirl number S∈[0,1]. Two... Read More about Formation and evolution of vortex rings with weak to moderate swirl.

Flow separation from polygonal cylinders in an incident flow (2023)
Journal Article
Masoudi, E., Sims-Williams, D., & Gan, L. (2023). Flow separation from polygonal cylinders in an incident flow. Physical Review Fluids, 8(1), Article 014701. https://doi.org/10.1103/physrevfluids.8.014701

In this paper, we carry out large eddy simulation of incident flow around polygonal cylinders of side number N = 5 − 8 at Reynolds number Re = 10 4 . In total, six incidence angles ( α ) are studied on each polygon between the face and the corner ori... Read More about Flow separation from polygonal cylinders in an incident flow.

Representative On-Road Aerodynamic Yaw Angle Distribution in China for Vehicle Development (2022)
Journal Article
Xiao, L., Wang, Q., Zhu, X., Bu, H., Huang, T., Yuan, X., …Sims-Williams, D. B. (2022). Representative On-Road Aerodynamic Yaw Angle Distribution in China for Vehicle Development. SAE International Journal of Passenger Vehicle Systems, 16(2), https://doi.org/10.4271/15-16-02-0008

Aerodynamic drag for road vehicles is most often assessed based on zero yaw conditions. The rise of electric vehicles in recent years put greater demand on how the vehicles perform in real-world conditions. Specifically, the aerodynamic drag performa... Read More about Representative On-Road Aerodynamic Yaw Angle Distribution in China for Vehicle Development.

Flow Enhancement of Tomographic Particle Image Velocimetry Measurements Using Sequential Data Assimilation (2022)
Journal Article
He, C., Wang, P., Liu, Y., & Gan, L. (2022). Flow Enhancement of Tomographic Particle Image Velocimetry Measurements Using Sequential Data Assimilation. Physics of Fluids, 34(3), Article 035101. https://doi.org/10.1063/5.0082460

Sequential data assimilation (DA) was performed on three-dimensional flow fields of a circular jet measured by tomography particle image velocimetry (tomo-PIV). The work focused on the in-depth analysis of the flow enhancement and the pressure determ... Read More about Flow Enhancement of Tomographic Particle Image Velocimetry Measurements Using Sequential Data Assimilation.

A review of experiments on stationary bluff-body wakes (2022)
Journal Article
Forouzi, B., He, S., Scarano, F., Gan, L., & Morton, C. (2022). A review of experiments on stationary bluff-body wakes. Physics of Fluids, 34(1), Article 011301. https://doi.org/10.1063/5.0077323

Experimental studies dealing with the wake of isolated stationary bluff-bodies are reviewed. After briefly recalling the pioneering works in this domain, the paper focuses on recent research conducted with the latest experimental methods and techniqu... Read More about A review of experiments on stationary bluff-body wakes.

Large Eddy Simulation of incident flows around polygonal cylinders (2021)
Journal Article
Masoudi, E., Gan, L., & Sims-Williams, D. (2021). Large Eddy Simulation of incident flows around polygonal cylinders. Physics of Fluids, 33(10), Article 105112. https://doi.org/10.1063/5.0063046

In this study, we carry out large eddy simulation (LES) of incident flow around polygonal cylinders of side number N = 5 − 8 at Reynolds number Re= 104 . In total, six incidence angles (α) are studied on each cylinder ranging from face to corner orie... Read More about Large Eddy Simulation of incident flows around polygonal cylinders.

Near wake flow features of polygonal cylinders in different incidence angles (2021)
Presentation / Conference
Masoudi, E., Gan, L., & Sims-Williams, D. (2021, September). Near wake flow features of polygonal cylinders in different incidence angles. Paper presented at UK Fluids Conference 2021, Online

In this study, large eddy simulation (LES) is used to simulate flow of incidence angle α around polygonal cylinders of side number N=5-8 at Reynolds number Re=10,000. Six incidence angles are studied on each cylinder, which covers the entire α spect... Read More about Near wake flow features of polygonal cylinders in different incidence angles.

Numerical investigation of shallow wake behind a patch of rigid emergent vegetation (2021)
Journal Article
Wang, J., Zhang, J., Liang, D., & Gan, L. (2021). Numerical investigation of shallow wake behind a patch of rigid emergent vegetation. Journal of Hydrodynamics, 33(4), 673-687. https://doi.org/10.1007/s42241-021-0071-3

The shallow water flow through and around a patch of rigid emergent vegetation was investigated numerically. The mean flow field and turbulent structures were studied, especially their dependence on the solid volume fraction (SVF) of the patch and th... Read More about Numerical investigation of shallow wake behind a patch of rigid emergent vegetation.

Diffraction waves on general two-legged rectangular floating breakwaters (2021)
Journal Article
Masoudi, E., & Gan, L. (2021). Diffraction waves on general two-legged rectangular floating breakwaters. Ocean Engineering, 235, https://doi.org/10.1016/j.oceaneng.2021.109420

In this paper, hydrodynamic characteristics of general two-dimensional rectangular floating breakwaters (FBs) with two legs in water of finite depth and infinite domain subjected to sinusoidal waves are studied using a numerical panel method. A param... Read More about Diffraction waves on general two-legged rectangular floating breakwaters.

Dynamics of the Jet Flow Issued from a Lobed Nozzle: Tomographic Particle Image Velocimetry Measurements (2021)
Journal Article
He, C., Liu, Y., & Gan, L. (2021). Dynamics of the Jet Flow Issued from a Lobed Nozzle: Tomographic Particle Image Velocimetry Measurements. International Journal of Heat and Fluid Flow, 89, Article 108795. https://doi.org/10.1016/j.ijheatfluidflow.2021.108795

This study focuses on the dynamics of the three-dimensional jet flow issued from a lobed nozzle. Flow field measurements were performed using a split-screen dual-camera tomographic particle image velocimetry (tomo-PIV) system. The lobed nozzle was co... Read More about Dynamics of the Jet Flow Issued from a Lobed Nozzle: Tomographic Particle Image Velocimetry Measurements.

A 4D-flow cardiovascular magnetic resonance study of flow asymmetry and haemodynamic quantity correlations in the pulmonary artery (2021)
Journal Article
Gbinigie, H., Coats, L., Parikh, J., Hollingsworth, K., & Gan, L. (2021). A 4D-flow cardiovascular magnetic resonance study of flow asymmetry and haemodynamic quantity correlations in the pulmonary artery. Physiological Measurement, 42(2), Article 025005. https://doi.org/10.1088/1361-6579/abdf3b

Objective: In this paper we elucidate the asymmetric flow pattern and the haemodynamic quantity distributions and correlations in the pulmonary artery (PA) vasculature in healthy adults having structurally normal hearts, to provide reference on the f... Read More about A 4D-flow cardiovascular magnetic resonance study of flow asymmetry and haemodynamic quantity correlations in the pulmonary artery.

Diffraction waves on large aspect ratio rectangular submerged breakwaters (2020)
Journal Article
Masoudi, E., & Gan, L. (2020). Diffraction waves on large aspect ratio rectangular submerged breakwaters. Ocean Engineering, 209, Article 107474. https://doi.org/10.1016/j.oceaneng.2020.107474

In this paper, hydrodynamic characteristics of two-dimensional submerged breakwaters in water of finite depth and infinite domain interacting with sinusoidal waves are studied from both analytical and numerical approaches. Added mass and damping coef... Read More about Diffraction waves on large aspect ratio rectangular submerged breakwaters.

Dynamics of Compact Vortex Rings Generated by Axial Swirlers at Early Stage (2020)
Journal Article
He, C., Gan, L., & Liu, Y. (2020). Dynamics of Compact Vortex Rings Generated by Axial Swirlers at Early Stage. Physics of Fluids, 32(4), Article 045104. https://doi.org/10.1063/5.0004156

This work concentrates on the study of flow dynamics of swirl vortex rings at the Reynolds number Re = 20 000 using a combination of the planar- and stereo-particle image velocimetry (PIV) measurements and dynamic delayed detached-eddy simulation. Pa... Read More about Dynamics of Compact Vortex Rings Generated by Axial Swirlers at Early Stage.

A Particle Image Velocimetry study of dual-rotor counter-rotating wind turbine near wake (2020)
Journal Article
Hollands, E., He, C., & Gan, L. (2020). A Particle Image Velocimetry study of dual-rotor counter-rotating wind turbine near wake. Journal of Visualization, 23(3), 425-435. https://doi.org/10.1007/s12650-020-00643-0

This experimental work studied the flow characteristics in the near wake region behind dual-rotor wind turbines using two-dimensional particle image velocimetry. Two auxiliary rotors of 50% and 80% scale of the main rotor were installed upwind and op... Read More about A Particle Image Velocimetry study of dual-rotor counter-rotating wind turbine near wake.

Instantaneous Pressure Determination from Unsteady Velocity Fields Using Adjoint-based Sequential Data Assimilation (2020)
Journal Article
He, C., Liu, Y., & Gan, L. (2020). Instantaneous Pressure Determination from Unsteady Velocity Fields Using Adjoint-based Sequential Data Assimilation. Physics of Fluids, 32(3), Article 035101. https://doi.org/10.1063/1.5143760

A sequential data assimilation (DA) method is developed for pressure determination of turbulent velocity fields measured by particle image velocimetry (PIV), based on the unsteady adjoint formulation. A forcing term F, which is optimized using the ad... Read More about Instantaneous Pressure Determination from Unsteady Velocity Fields Using Adjoint-based Sequential Data Assimilation.

The role of flow rotation in the adult right atrium: a 4D flow cardiovascular magnetic resonance study (2020)
Journal Article
Dewhurst, P., Coats, L., Parikh, J. D., Hollingsworth, K. G., & Gan, L. (2020). The role of flow rotation in the adult right atrium: a 4D flow cardiovascular magnetic resonance study. Physiological Measurement, 41(3), Article 035007. https://doi.org/10.1088/1361-6579/ab7d77

Objective: In healthy adults, the right atrium (RA) serves as a reservoir for the systemic flow return from the superior vena cava (SVC) and inferior vena cava (IVC), preparing the two flows to be transferred to the right ventricle (RV) and pulmonary... Read More about The role of flow rotation in the adult right atrium: a 4D flow cardiovascular magnetic resonance study.

Experimental study of swirling flow characteristics in a semi cylinder vortex cooling configuration (2020)
Journal Article
Fan, X., He, C., Gan, L., Li, L., & Du, C. (2020). Experimental study of swirling flow characteristics in a semi cylinder vortex cooling configuration. Experimental Thermal and Fluid Science, 113, Article 110036. https://doi.org/10.1016/j.expthermflusci.2019.110036

This study utilised planar Particle Image Velocimetry (PIV) to investigate the flow characteristics in a semi cylindrical confinement with 2 jet inlets. The water based experimental study aims to understand the basic flow behaviour in a gas turbine l... Read More about Experimental study of swirling flow characteristics in a semi cylinder vortex cooling configuration.

The formation and evolution of turbulent swirling vortex rings generated by axial swirlers (2019)
Journal Article
He, C., Gan, L., & Liu, Y. (2020). The formation and evolution of turbulent swirling vortex rings generated by axial swirlers. Flow, Turbulence and Combustion, 104(4), 795-816. https://doi.org/10.1007/s10494-019-00076-2

The present work investigates the formation process and early stage evolution of turbulent swirling vortex rings, by using planar Particle Image Velocimetry (PIV) and Large Eddy Simulation (LES). Vortex rings are produced in a piston-nozzle arrangeme... Read More about The formation and evolution of turbulent swirling vortex rings generated by axial swirlers.

Scaling of the time-mean characteristics in the polygonal cylinder near-wake (2019)
Journal Article
Wang, Q., Xu, S., Gan, L., Zhang, W., & Zhou, Y. (2019). Scaling of the time-mean characteristics in the polygonal cylinder near-wake. Experiments in Fluids, 60, Article 181. https://doi.org/10.1007/s00348-019-2835-x

The near wake of the polygonal cylinder with the side number N = 3 ~ ∞ is systematically studied based on particle image velocimetry (PIV) and load-cell measurements. Each cylinder is examined for two orientations, with either one leading side or lea... Read More about Scaling of the time-mean characteristics in the polygonal cylinder near-wake.

Vortex evolution in the near wake behind polygonal cylinders (2019)
Journal Article
Wang, Q., Gan, L., Xu, S., & Zhou, Y. (2020). Vortex evolution in the near wake behind polygonal cylinders. Experimental Thermal and Fluid Science, 110, Article 109940. https://doi.org/10.1016/j.expthermflusci.2019.109940

The near wake of the polygonal cylinder with the side number N = 3~∞ is systematically studied using particle image velocimetry (PIV) at Re = 1.6 × 104. The proper orthogonal decomposition (POD) analysis is carried out to extract the large-scale cohe... Read More about Vortex evolution in the near wake behind polygonal cylinders.

Non-hydrostatic modelling of shallow water flow around a circular array of emergent cylinders (2019)
Journal Article
Wang, J., Zhang, J., Liang, D., & Gan, L. (2020). Non-hydrostatic modelling of shallow water flow around a circular array of emergent cylinders. Journal of Hydroinformatics, 22(1), 20-32. https://doi.org/10.2166/hydro.2019.018

This paper focuses on the investigation of the wake flow around a circular patch of cylinders with different solid volume fractions (SVF). The wake flow pattern was found to be dependent on the SVF and the flow stability factor S. A non-hydrostatic m... Read More about Non-hydrostatic modelling of shallow water flow around a circular array of emergent cylinders.

Wake modes behind a streamwisely-oscillating cylinder at constant and ramping frequencies (2019)
Journal Article
Hu, Z., Liu, J., Gan, L., & Xu, S. (2019). Wake modes behind a streamwisely-oscillating cylinder at constant and ramping frequencies. Journal of Visualization, 22(3), 505-527. https://doi.org/10.1007/s12650-019-00554-9

studied at Reynolds number Re = 360–460 which are observed by laser-induced fluorescence flow visualization technique. The forcing frequency fe ranges from 0 to 6.85 fs , where fs is the vortex shedding frequency behind a stationary cylinder, and the... Read More about Wake modes behind a streamwisely-oscillating cylinder at constant and ramping frequencies.

Data assimilation and resolvent analysis of turbulent flow behind a wall-proximity rib (2019)
Journal Article
He, C., Liu, Y., Gan, L., & Lesshafft, L. (2019). Data assimilation and resolvent analysis of turbulent flow behind a wall-proximity rib. Physics of Fluids, 31(2), Article 025118. https://doi.org/10.1063/1.5074151

This study aims to detect the unsteady features of the turbulent flow behind a wall-proximity rib using resolvent analysis, based on the mean flow field determined using an adjoint-based data assimilation (ABDA) model. The rib is located at gap ratio... Read More about Data assimilation and resolvent analysis of turbulent flow behind a wall-proximity rib.

A data assimilation model for turbulent flows using continuous adjoint formulation (2018)
Journal Article
He, C., Liu, Y., & Gan, L. (2018). A data assimilation model for turbulent flows using continuous adjoint formulation. Physics of Fluids, 30(10), Article 105108. https://doi.org/10.1063/1.5048727

A generalized data assimilation model for turbulent flows using the continuous adjoint formulation is proposed. Within this formulation, the Spalart–Allmaras turbulence model is modified by adding a correction function β as a spatially varying coeffi... Read More about A data assimilation model for turbulent flows using continuous adjoint formulation.

The size and lifetime of organised eddies in a non-solid-body rotating turbulence experiment (2018)
Journal Article
Gan, L., & Maffioli, A. (2018). The size and lifetime of organised eddies in a non-solid-body rotating turbulence experiment. European Journal of Mechanics - B/Fluids, 74, 41-49. https://doi.org/10.1016/j.euromechflu.2018.10.026

This paper follows our previous study of forced non-solid-body rotating turbulence and summarises results on the eddy size and lifetime in the same flow. The experiment is conducted in a dodecagonal tank (Rt ≈ 1m in radius and 2m in height) and the b... Read More about The size and lifetime of organised eddies in a non-solid-body rotating turbulence experiment.

Experimental study of flow around polygonal cylinders (2016)
Journal Article
Xu, S., Zhang, W., Gan, L., Li, M., & Zhou, Y. (2017). Experimental study of flow around polygonal cylinders. Journal of Fluid Mechanics, 812, 251-278. https://doi.org/10.1017/jfm.2016.801

The wake of polygonal cylinders with side number N=2∼∞N=2∼∞ is systematically studied based on fluid force, hot-wire, particle image velocimetry and flow visualisation measurements. Each cylinder is examined for two orientations, with a flat surface... Read More about Experimental study of flow around polygonal cylinders.

Flow interaction between a streamwise oscillating cylinder and a downstream stationary cylinder (2016)
Journal Article
Xu, S., Gan, L., & Zhou, Y. (2016). Flow interaction between a streamwise oscillating cylinder and a downstream stationary cylinder. Experiments in Fluids, 57(11), Article 173. https://doi.org/10.1007/s00348-016-2265-y

In this paper, we present some experimental results about the physical effects of a cylinder’s streamwise oscillation motion on a downstream one in a tandem arrangement. The upstream cylinder undergoes a controlled simple harmonic oscillation at ampl... Read More about Flow interaction between a streamwise oscillating cylinder and a downstream stationary cylinder.

Evolution of turbulence and in-plane vortices in the near field flow behind multi-scale planar grids (2016)
Journal Article
Gan, L., & Krogstad, P. (2016). Evolution of turbulence and in-plane vortices in the near field flow behind multi-scale planar grids. Physics of Fluids, 28(8), Article 085101. https://doi.org/10.1063/1.4960025

In this experimental work, we carry out detailed two-dimensional particle image velocimetry investigations for the near field wakes behind a conventional and two multi-scale planar grids, using stitched camera fields of view. Statistical independent... Read More about Evolution of turbulence and in-plane vortices in the near field flow behind multi-scale planar grids.

Transient growth associated with secondary vortices in ground/vortex interactions (2016)
Journal Article
Stuart, T., Mao, X., & Gan, L. (2016). Transient growth associated with secondary vortices in ground/vortex interactions. AIAA Journal, 54(6), 1901-1906. https://doi.org/10.2514/1.j054484

The interaction of an isolated trailing vortex and the ground is investigated. An unsteady unperturbed flow is first calculated through a two-dimensional direct numerical simulation and then used as base flow for linear transient growth studies. The... Read More about Transient growth associated with secondary vortices in ground/vortex interactions.

An experimental investigation of forced steady rotating turbulence (2016)
Journal Article
Gan, L., Baqui, B., & Maffioli, A. (2016). An experimental investigation of forced steady rotating turbulence. European Journal of Mechanics - B/Fluids, 58, 59-69. https://doi.org/10.1016/j.euromechflu.2016.03.005

This paper presents some of the principal findings of an experimental investigation of forced statistically steady turbulence in a rapidly rotating background. The experiment is conducted in a large cylindrical mixing tank and bulk rotation is produc... Read More about An experimental investigation of forced steady rotating turbulence.

Detection of passive scalar interface directly from PIV particle images in inhomogeneous turbulent flows (2016)
Journal Article
Gan, L. (2016). Detection of passive scalar interface directly from PIV particle images in inhomogeneous turbulent flows. Flow, Turbulence and Combustion, 97(1), 141-170. https://doi.org/10.1007/s10494-015-9691-4

This article proposes a technique to estimate the cross-sectional scalar interface (outer boundary) in an inhomogeneous turbulent flow from a conditioned particle image velocimetry (PIV) experiment, which is suitable for medium to high Reynolds numbe... Read More about Detection of passive scalar interface directly from PIV particle images in inhomogeneous turbulent flows.

Invariants of the reduced velocity gradient tensor in turbulent flows (2013)
Journal Article
Cardesa, J., Mistry, D., Gan, L., & Dawson, J. (2013). Invariants of the reduced velocity gradient tensor in turbulent flows. Journal of Fluid Mechanics, 716, 597-615. https://doi.org/10.1017/jfm.2012.558

In this paper we examine the invariants p and q of the reduced 2×2 velocity gradient tensor (VGT) formed from a two-dimensional (2D) slice of an incompressible three-dimensional (3D) flow. Using data from both 2D particle image velocimetry (PIV) m... Read More about Invariants of the reduced velocity gradient tensor in turbulent flows.

On the drag of turbulent vortex rings (2012)
Journal Article
Gan, L., Dawson, J., & Nickels, T. (2012). On the drag of turbulent vortex rings. Journal of Fluid Mechanics, 709, 85-105. https://doi.org/10.1017/jfm.2012.322

In this paper the pressure field during the early development of turbulent vortex rings at two Reynolds numbers is determined using temporally resolved two-dimensional and stereoscopic particle image velocimetry (PIV). The pressure gradient terms are... Read More about On the drag of turbulent vortex rings.

Stereoscopic PIV and Its Applications on Reconstruction Three-Dimensional Flow Field (2012)
Book Chapter
Gan, L. (2012). Stereoscopic PIV and Its Applications on Reconstruction Three-Dimensional Flow Field. In G. Cavazzini (Ed.), The Particle Image Velocimetry - Characteristics, Limits and Possible Applications. https://doi.org/10.5772/48017

Various concepts involving in the stereoscopic PIV are very briefly summarised in this section. For more details, readers are recommended to read Lavision (2007); Prasad (2000); Raffel et al. (2007). Stereoscopic PIV adopts two digital cameras viewin... Read More about Stereoscopic PIV and Its Applications on Reconstruction Three-Dimensional Flow Field.

An experimental study of a turbulent vortex ring: a three-dimensional representation (2011)
Journal Article
Gan, L., Dawson, J., & Nickels, T. (2011). An experimental study of a turbulent vortex ring: a three-dimensional representation. Experiments in Fluids, 51(6), 1493-1507. https://doi.org/10.1007/s00348-011-1156-5

An experimental study of turbulent vortex rings during their early development (2010)
Journal Article
GAN, L., & Nickels, T. (2010). An experimental study of turbulent vortex rings during their early development. Journal of Fluid Mechanics, 649, 467-496. https://doi.org/10.1017/s0022112009993971

In this paper, the early development of turbulent vortex rings at two Reynolds numbers is studied using two-dimensional and stereoscopic particle image velocimetry (PIV). In the late 1980s, a similarity theory of turbulent vortex rings was proposed a... Read More about An experimental study of turbulent vortex rings during their early development.