B. Zang

B. Zang
University of Bristol | UB · Department of Aerospace Engineering

BEng, Ph.D

About

76
Publications
24,590
Reads
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413
Citations
Citations since 2017
71 Research Items
410 Citations
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
Introduction
Experimental aerodynamics and aeroacoustics, including the fundamental phenomenon in aerofoils and jets, with further interests in control strategies for noise mitigation. Besides the primary work, developing numerical method is another element of personal interest.

Publications

Publications (76)
Article
Full-text available
Numerical performance of rhoCentralFoam, a compressible solver in OpenFOAM, was studied by modeling round supersonic free jets with varying nozzle exit conditions through Reynolds-Averaged Navier-Stokes approach. To understand the behavior and accuracy of the solver, simulations were conducted at four different nozzle pressure ratios (i.e. NPR = 2....
Article
In this paper, a novel mapping approach through the use of adaptive mapping functions is introduced for high order weighted essentially non-oscillatory (WENO) methods. The new class of adaptive mapping functions are designed to adjust themselves to the solution based on a simple parameter calculated using the smoothness indicators that are readily...
Article
Full-text available
The present study concerns an experimental investigation of the aerodynamic and aeroacoustic characteristics of a sinusoidally oscillating NACA 0012 aerofoil. The experiments were conducted in an aeroacoustic wind tunnel with a uniquely designed Kevlar-walled test section. Prior to experiments, these Kevlar walls were calibrated carefully and shown...
Article
The present study experimentally investigates the effective reduction of wake-aerofoil interaction noise in a tandem aerofoil configuration using trailing-edge sawtooth serrations. The far-field noise results clearly show that at the ‘head-on’ wake impingement, the use of sawtooth serrations on the trailing-edge of the front aerofoil can lead to su...
Article
Full-text available
In this study, a new family of rational mapping functions gRM(ω,k,m,s) is introduced for seventh-order WENO schemes. gRM is a more general family of mapping functions, which includes other mapping functions such as gM and gIM as special cases. The mapped WENO scheme WENO-IM(2,0.1), which uses gIM, performs excellently at fifth order but rather poor...
Conference Paper
This paper discusses the wind tunnel test of a 37.5% scale model of a blended wing body unmanned aerial vehicle. The model was mounted on a fixed belly-fairing sting, and the pitch variation was facilitated via a linear actuator. The model and set-up were directly mounted on a force plate placed underneath the tunnel floor. Aerodynamic loads were a...
Conference Paper
Experiments were carried out within an aeroacoustic wind tunnel facility to investigate acoustic scattering and shielding effects of a propeller being placed above a semi-infinite flat plate. The position of the flat plate trailing edge was adjusted relative to the propeller which was tested in static conditions with a constant rotational rate of 5...
Article
This paper investigates the hydrodynamic near-field of a NACA 16-616 aerofoil over a range of angles-of-attack, encompassing the pre-stall, stall and post-stall flow regimes. In both the static pressure and the pressure fluctuation results, it is shown that each flow regime is easily distinguished, and it is further shown that each regime has diffe...
Conference Paper
This paper investigates the hydrodynamic near-field and predicted radiated acoustic far-field of three NACA-series airfoils, namely the NACA 16-616, NACA 16-506, and NACA 0024 profiles, over a range of angles of attack, encompassing the pre-stall, stall, and post-stall flow regimes. In both the static pressure and the pressure fluctuation results,...
Conference Paper
A series of experiments were conducted in an aeroacoustic wind tunnel facility to investigate the aerodynamic performance and noise characteristics of propellers with various modifications to its tip geometry. A baseline propeller was designed for static hover conditions. The blade was adapted with the intention to reduce, divert or eliminate the b...
Conference Paper
A set of experiments were carried out within an aeroacoustic wind tunnel facility to investigate parametrically the acoustic interactions of a propeller positioned above two flat plates of varying dimensions. A propeller was tested at a constant rotational rate of 7000 RPM in static conditions in three test configurations; an isolated propeller, a...
Conference Paper
This paper presents an experimental study on rod-airfoil interaction noise and the effectiveness of the application of leading-edge serrations as a passive control method for reducing the interaction noise. A rod with 10 mm diameter and a NACA 0012 airfoil has been set up in tandem configuration, with free-stream velocity varied from 8 m/s to 32 m/...
Conference Paper
The TNO type surface pressure spectrum models are used to represent the surface pressure spectrum beneath a turbulent boundary layer, with a focus on adverse pressure gradient airfoil flows and associated trailing edge noise prediction. The input for the models is provided via the Wall Modelled Large Eddy Simulation (WMLES) performed using the high...
Conference Paper
This paper presents an experimental study on the effectiveness of sinusoidal wavy-shaped and vibrissa-shaped cylinders as a passive control method on mitigating the aerodynamic noise of flow past a cylinder. A total of five differently-shaped cylinders with similar total volume, namely a circular cylinder with 22mm diameter, two sinusoidal wavy cyl...
Conference Paper
Accurate and efficient prediction of propeller aerodynamic and acoustic performance is of paramount importance to the analysis and design of various urban air mobility concepts emerging over the last decade. This paper presents the first exploratory effort in developing a data-driven framework to improve the prediction of propeller performance. In...
Conference Paper
The effects of a fixed splitter plate mounted on the downstream side of a circular cylinder to reduce aeolian tone is investigated experimentally. The diameter of the cylinder D is 22mm. Three parameters are considered: The length of the plates (L=0.5D, 1.0D, 1.5D), the thickness of the plates (h=1mm and 2mm), and the Reynolds numbers (Re = 2.18×〖1...
Article
This experimental study investigates the effect of biologically inspired finlets on the reduction of trailing-edge noise of a NACA 0012 airfoil. At a chord-based Reynolds number of 400,000, the far-field noise measurements show that the finlets are capable of reducing the trailing-edge noise effectively from 1000 to 4000 Hz with up to 6 dB reductio...
Article
Full-text available
A hybrid numerical flux scheme is proposed by adapting the carbuncle-free modified Harten-Lax-van Leer contact (HLLCM) scheme to smoothly revert to the Harten-Lax-van Leer contact (HLLC) scheme in regions of shear. This hybrid scheme, referred to as the HLLCT scheme, employs a novel, velocity-based shear sensor. In contrast to the non-local pressur...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2021-2538.vid Understanding of the turbulent flow generated by the flow past a bluff body, such as cylinder, is very pertinent to many modern engineering applications. This paper aims to investigate the effect of spanwise length of flow past a circular cylinder on the near-field aerodynamic charact...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2021-2263.vid In the present study, a range of different surface treatments is considered for the attenuation of flat plate trailing edge noise through reducing the power spectral density of the unsteady surface pressure fluctuations near the trailing edge. This approach is inspired by the recent s...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2021-2112.vid This study experimentally investigates the near-field flow characteristics associated with the capability for trailing edge noise reduction of a selected finlet surface treatment applied on a NACA 0012 airfoil. It continues from a previous study, in which a variation of finlet paramet...
Conference Paper
Full-text available
The present study investigates the near-field and wake characteristics of a NACA 0012 airfoil at stall condition, using compressible large eddy simulations (LES). The LES results are compared and validated directly with in-house experimental data with similar angle of attack, α = 14.5 • , chord length and trip configurations. The numerical results...
Article
Jet screech is an intense pure tone which has attracted decades of research interest due to its possible detrimental effect on engineering structures. Its modes and closure mechanisms have been investigated analytically, experimentally, and numerically; however, there are still outstanding questions regarding the generation and propagation of insta...
Article
Short-time Proper Orthogonal Decomposition (POD) is proposed as an image-based technique to study the transient jet screech characteristics of moderately under-expanded supersonic jets emanating from a circular baseline and two bevelled nozzles. Time-resolved schlieren imaging of turbulent flow structures were performed with an ultrahigh-speed schl...
Article
Collision of vortex rings upon V-walls - Volume 899 - T. H. New, J. Long, B. Zang, Shengxian Shi
Article
In aerodynamic and aeroacoustic research, pressure–velocity correlation and coherence have been increasingly utilised to identify and understand the motions of large-scale structures and their collective effects on the surface pressure fluctuations due to the boundary layer. Nevertheless, when a relatively sharp transition from turbulent boundary l...
Article
Passive noise control for a tandem NACA 65-710 airfoil configuration is experimentally investigated by applying leading-edge serrations on the rear airfoil. With a sliding side-plate mechanism that allows the rear airfoil to move in the vertical direction relative to the front airfoil, the position of maximum turbulence interaction noise is first i...
Conference Paper
Full-text available
The present study investigates the flow dynamics and self-noise generated by a highly instrumented NACA 65-410 airfoil, which aims to provide a better understanding of the near-field aerodynamic and aeroacoustic characteristics and their correlation with airfoil noise. The experiments have been carried out in an aeroacoustic wind tunnel at two mode...
Conference Paper
Full-text available
The present study experimentally investigates a NACA 65-410 cambered airfoil under oscillating motions at moderate Reynolds number. Two oscillation frequencies were tested, which corresponded to a reduced frequency factor, below and above that representative of dynamic stall (i.e. kr > 0.05). Effects of the oscillation frequency, oscillation amplit...
Article
A quantitative rainbow schlieren study was conducted on an over-expanded jet at nozzle pressure ratio of 2.8, based on two different schlieren set-ups: the standard z-type and a single-mirror schlieren set-up. The technique used a single, weak focal-length lens placed in the field of view of the system to provide the calibration information require...
Conference Paper
Full-text available
This paper investigates the hydrodynamic near-field and acoustic far-field of a NACA 0012 airfoil undergoing dynamic stall. It is shown that the unsteady surface pressure fluctuation spectra can increase substantially when an airfoil experiences dynamic stall. Similarly, far-field noise increases have been observed, while the spanwise surface press...
Article
Full-text available
In this paper, a hybrid method suitable for solving the Euler equations using high order methods has been proposed. The method was implemented and validated with a seventh order WENO scheme in OpenFOAM®. The hybrid method combines a simple MUSCL-type flux approach and a characteristic flux approach. In the MUSCL-type flux approach, the inviscid flu...
Conference Paper
Full-text available
The effect of leading edge serrations on the surface pressure fluctuation spectra and boundary layer quantities of a NACA 0012 airfoil has been investigated experimentally, with an emphasis on reducing airfoil separation and stall noise. Five leading edge serration add-ons with various serration heights and wavelengths have been tested in conjuctio...
Conference Paper
Full-text available
Stall and separation noise can be major contributors to the noise emission of rotating blades, such as wind turbines, propellers and fans among others. Hence, this paper experimentally investigates the effects a separated boundary layer has on near-field flow structures, on turbulent surface pressure fluctuation statistics, and therefore on noise r...
Presentation
Full-text available
An experimental study has been conducted on the application of rainbow schlieren with a single-mirror schlieren system for the study of over- and moderately under-expanded jets.
Conference Paper
The formulation of rotated Riemann solvers proposed by Ren [1] is modified slightly through the introduction of a shock sensor to ensure that the rotated scheme is only applied near shocks. This modified formulation is applied with rotated HLLC scheme proposed by Huang, et al. [2] to demonstrate that restricting the action of the rotated scheme to...
Conference Paper
An experimental study has been conducted on the application of rainbow schlieren with a single-mirror schlieren system for the study of over-and under-expanded jets. The technique used a weak lens in the field-of-view to provide calibration information for the extraction of quantitative data. The calibration image required post-processing procedure...
Chapter
The present study numerically investigates supersonic jet flows issued at M = 1.45 from a beveled nozzle with 60° inclination. Utilizing rhoCentralFoam solver in OpenFOAM, unsteady Reynolds-averaged Navier-Stokes (RANS) simulations were performed with two nozzle pressure ratios (NPRs) of 2.8 and 4, corresponding to over- and under-expanded exit con...
Article
Detailed experimental comparisons had been conducted between calibrated and rainbow schlieren on perfectly- and under-expanded axisymmetric jets through a modified Z-type schlieren system. The techniques were implemented by using a weak lens in the field-of-view to provide calibration information for the extraction of quantitative density gradients...
Article
Full-text available
The near wake of a sinusoidal wavy cylinder is investigated using time-resolved particle image velocimetry (TR-PIV). The wavy cylinder has a large spanwise wavelength of six mean diameters. TR-PIV measurements are taken in three orthogonal planes in the near wake at a Reynolds number Re = 3.0 × 10³. Flow structures are documented in detail, in term...
Article
Full-text available
The double Mach reflection (DMR) problem is an important test case for the assessment of the resolution of Euler codes. The initial and boundary conditions specified in the conventional setup of the problem result in the formation of undesirable numerical artefacts which interfere with the solution. In this study, two alternative setups are propose...
Conference Paper
Full-text available
An experimental study on vortex-rings impacting upon V-shaped walls had been conducted using planar laser-induced fluorescence (PLIF) visualizations and time-resolved particle-image velocimetry (TR-PIV) measurements in a water tank. Generated via a "cylindrical slug" approach with a high-torque stepping motor and piston-cylinder setup, Re=1000 circ...
Presentation
Full-text available
The presentation referees on the latest results on the comparison of Calibrated and Rainbow Schlieren for use in the supersonic jet experiments conducted as part of the project "Novel non-intrusive measurements and simulations of supersonic flow and noise." Current results indicate that, for the schlieren system currently in use, Calibrated Schlier...
Conference Paper
Full-text available
An experimental study has been conducted comparing the use of Calibrated and Rainbow Schlieren on underexpanded asymmetric jets using a modified Z-type schlieren system in the campaign. A weak plano-convex lens was placed in the schlieren mirror field of view just upstream of the jet nozzle lip to provide the calibration information necessary for t...
Conference Paper
Full-text available
In this study, a new family of rational mapping functions g RM (ω; k, m, s) is introduced for seventh order WENO schemes. gRM is a more general family of mapping functions which includes other mapping functions such as gM [1] and gIM [2] as special cases. The mapped WENO scheme WENO-IM(2,0.1) which uses gIM(ω; 2, 0.1) performs excellently at fifth...
Data
Vortex-ring collision Re=4000 D=1d (half-speed)
Data
Vortex-ring collision Re=4000 D=2d (half-speed)
Data
Vortex-ring collision Re=4000 D=4d (half-speed)
Article
Full-text available
Vortical structures and behaviour associated with vortex-ring collisions upon round cylinders with different cylinder-to-vortex-ring diameter ratios were studied using laser-induced fluorescence and time-resolved particle-image velocimetry techniques. Circular vortex rings of Reynolds number 4000 and three diameter ratios of $D/d=1$ , 2 and 4 were...
Conference Paper
Full-text available
Experimental work on calibrated Schlieren has been conducted on a baseline axisymmetric and an asymmetric supersonic jet operating at a nozzle pressure ratio of 5. The technique was implemented with a weak lens in the field-of-view to provide calibration information to enable extraction of quantitative flow data, and a 6 th-order polynomial curve-f...
Conference Paper
Full-text available
The present study numerically investigates supersonic jet flows issued at M=1.45 from a beveled nozzle with 60deg inclination. Utilizing rhoCentralFoam solver in OpenFOAM, unsteady Reynolds-averaged Navier-Stokes (RANS) simulations were performed with two nozzle pressures ratios (NPR) of 2.8 and 4, corresponding to over-and under-expanded exit cond...
Article
Full-text available
The present study examines the near-field flow developments and dynamics of parallel twin jets in cross-flow (TJICF) configured with jet-to-jet separation distances of 1.5 to 3 jet diameters (D) and velocity ratios of 2, 4, and 6. Both laser-induced fluorescence and particle-image velocimetry measurements were made along the streamwise and cross-st...
Conference Paper
Full-text available
The present paper reports upon a numerical study on an underexpanded supersonic jet at Mach=1.45 through the use of OpenFOAM® and subsequent comparisons to results obtained through a commercial CFD solver. Results from 2D and 3D unsteady RANS simulations exhibit very good agreements between the two solvers in terms of the jet exit velocity profiles...
Article
Full-text available
Flow behaviour of a hydrofoil with leading-edge tubercles was experimentally studied using particle image velocimetry technique at a Reynolds number of Re=1.4×104. Four angles-of-attack of α=0°, 10°, 15° and 20° were considered. Proper orthogonal decomposition (POD) technique was used to analyse the instantaneous velocity fields and derive informat...
Article
Full-text available
This paper reports upon a laser-induced fluorescence visualization and time-resolved particle image velocimetry study to resolve the detailed dynamics associated with Re = 2000 and 4000 circular vortex rings colliding with 30°–75° inclined surfaces. Two-dimensional visualization results show that larger inclination angles lead to increasingly rapid...
Article
Full-text available
An experimental study has been conducted on tandem twin jets in cross-flow (JICF) in close proximity to investigate the relationships between their trajectories, separation distances and velocity ratios. Results show that the front and rear jets, each with initially distinct jet trajectory, merge into a single trajectory shortly after they exhaust...
Article
Experiments on twin circular free jets with separation-distances of 1.5, 2.0 and 3.0 jet diameters (D) have been conducted using time-resolved particle-image velocimetry technique. Mean velocity results show that the merging of inner shear layers of the twin jets occurs nearer to the jet exit surface as the separation-distance decreases. Along the...
Conference Paper
Full-text available
The present paper studies the near-field flow structures and dynamics for the jet-in-cross-flow phenomenon involving two circular jets aligned in tandem configuration. To investigate the effects of jet-to-cross-flow velocity-ratio and jet-to-jet separation distance on the vortical behaviours of the twin jets and to compare them with that of the sin...

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