• Exp. Fluids (IF 2.443) Pub Date : 2020-03-30
Thomas J. Lambert, Bojan Vukasinovic, Ari Glezer

Abstract The coupling between a pitching axisymmetric bluff body and its wake is modified in wind tunnel experiments using controlled interactions between fluidic actuators and the cross-flow over its aft end. The model trajectory is controlled using eight servo-controlled support wires with inline force transducers that are operated in closed loop with feedback from a motion analysis system which

更新日期：2020-03-31
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-27
M. M. Campagna, M. E. H. van Dongen, D. M. J. Smeulders

Abstract A novel design of a pulse expansion wave tube (PEWT) for the study of homogeneous nucleation in mixtures of vapours and gases is presented. The main difference with the previous design consists in a test section with flat walls, which avoid that optical windows and pressure transducers do affect the flow field locally. Additionally, the test section length is reduced by a factor two. The performance

更新日期：2020-03-27
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-25
Mark A. Brend, Paul A. Denman, Jon F. Carrotte

Abstract The three-dimensional flows within a full featured, unmodified annular gas turbine combustor have been investigated using a scanned stereoscopic PIV measurement technique. Volumetric measurements have been achieved by rigidly translating a stereoscopic PIV system to scan measurements around the combustor, permitting reconstruction of volumetric single-point statistics. Delivering the measurements

更新日期：2020-03-26
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-25
Robert B. Panco, Edward P. DeMauro

Abstract Experiments were performed within the Rutgers University Mach 3.4 supersonic wind tunnel to quantify the turbulent boundary layer in the test section, using stereoscopic particle image velocimetry (SPIV). Seeding of the tunnel was accomplished using atomized mineral oil, resulting in a Stokes number of 0.09. The Reynolds number based on momentum thickness and the friction-velocity Reynolds

更新日期：2020-03-26
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-23
Felix Greiffenhagen, Jakob Woisetschläger, Johannes Gürtler, Jürgen Czarske

The original published article contains error in equation and reference.

更新日期：2020-03-24
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-23
Connor C. McDougall, W. Schuyler Hinman, Craig T. Johansen, Brett F. Bathel, Jennifer A. Inman, Paul M. Danehy

Abstract Nitric oxide planar laser-induced fluorescence was performed to measure the wall-normal distribution of static temperature through a hypersonic boundary layer. A 10-degree half-angle wedge model was oriented at a 5-degree angle of attack in the NASA Langley 31-in Mach 10 facility, resulting in a 5-degree flow turning angle and an edge Mach number of 7.6. Nitric oxide was seeded through a spanwise

更新日期：2020-03-24
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-23
Lingrui Jiao, Xu Liu, Zheyu Shi, Weiguo Zhang, Lei Liang, Xi Chen, Qijun Zhao, Di Peng, Yingzheng Liu

Abstract Pressure-sensitive paint (PSP) has become an important technique for global pressure measurement on rotating surfaces such as helicopter rotor blades. Due to the temperature sensitivity of PSP, it is essential to apply accurate temperature correction method in PSP measurements. In previous studies, one-dimensional (1D) correction methods were generally adopted which only considered the radial

更新日期：2020-03-24
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-23
Sungmin Lee, Hakyoon Song, Gisu Park

Abstract Strut-support interference effects were investigated at a nominal Mach number of 6. Cylinder and rhombus models are used; moreover, models called half shock-bump (SB) and SB applied to the front and both sides of the shock-bump shape are used. This is beneficial for free-stream flow recovery around the model surface by bumping the compression and expansion waves at a unit Reynolds number of

更新日期：2020-03-24
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-19
Elliott W. Lewis, Timothy C. W. Lau, Zhiwei Sun, Zeyad T. Alwahabi, Graham J. Nathan

Abstract We present the use of two-colour toluene planar laser-induced fluorescence (LIF) to obtain spatially resolved measurements of the gas temperature ($$T_\mathrm{g}$$) in a particle-laden turbulent flow under sufficiently dense particle loading that the interference from laser interactions with the particles is significant. The effect of the ratio of volumetric flow rates of the particle phase

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-19
Kyungduck Yoon, Shijie Qin, Siyao Shao, Jiarong Hong

Abstract Our study provides the first experimental investigation of the internal flows of ventilated partial cavitation (VPC) formed by air injection behind a backward-facing step. The experiments are conducted using flow visualization and planar particle image velocimetry with fog particles for two different cavity regimes of VPC, i.e., open cavity (OC) and two-branch cavity (TBC), under various ranges

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-18
Johannes Palmer, Leif Schumacher, Manuel A. Reddemann, Valeri Kirsch, Reinhold Kneer

Abstract The relatively new thermometry technique “pulsed 2cLIF with MDR-enhanced energy transfer” is tested for the first time on micro-droplet streams in a heated air flow. The method allows simultaneous measurements of the droplet internal temperature-field, droplet size and droplet velocity. Plausibility of the measurement results is evaluated by comparing results of various experimental conditions

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-17
Shivam Barwey, Harish Ganesh, Malik Hassanaly, Venkat Raman, Steven Ceccio

Abstract Time-resolved X-ray densitometry void fraction measurements and accompanying acoustic emissions have revealed that partial cavity shedding on a hydrofoil can be multimodal, with spontaneous changes in shedding sequence (referred to here as cavitation style) for fixed inlet flow conditions. These spontaneous, intermittent transitions between two physically different shedding styles are examined

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-16
David Huynh, Beverley McKeon

Abstract A series of experiments have been performed to study the response of a compliant (gelatin) surface to a turbulent boundary layer that has been forced by dynamic roughness. Through the synthetic flow structure generated by dynamic roughness, this work reduces the complexity of the fluid–structural problem in order to develop a fundamental framework with which to study flow control mechanisms

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-16
Nicole Mehr, Clément Roques, Yves Méheust, Skip Rochefort, John S. Selker

Abstract Unexpected interface complexities were found resulting from the miscible displacement of saltwater by a miscible shear-thinning solution (xanthan gum) in a radial Hele-Shaw cell, for both convergent and divergent flow. Such complex patterns have not been described before for either Newtonian or non-Newtonian solutions. A more viscous solution was injected into the cell to displace a less viscous

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-16
G. Dolfo, J. Vigué, D. Lhuillier

Abstract Stokes calculated the force exerted by the surrounding fluid on a sphere and on a cylinder in oscillating motion. Although these results are valid only if the Reynolds number Re is very small, $${\text {Re}}\ll 1$$, all the tests on macroscopic spheres have been made with Re larger than 20. Here, we describe an experiment which measures the drag force on an oscillating sphere with small values

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-16

Abstract Non-circular jets, particularly elongated jets and jets with sharp corners, are of interest due to their enhanced large- and small-scale mixing and combustion stability. Non-circular jet geometries such as elliptic, triangular, rectangular, and square have been extensively studied. The non-uniform curvature and elongated design of elliptic and rectangular jets has been shown to facilitate

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-09
Patrick Russell, James Venning, Bryce W. Pearce, Paul A. Brandner

Abstract Calibration of the Mie Scattering Imaging (MSI) technique for microbubble size and concentration measurement in hydrodynamic test facilities is investigated. Monodisperse bubbles are generated by a microfluidic ‘T’ junction, and individual bubbles simultaneously imaged with shadowgraphy and MSI. Nominal bubble diameters between 30 and $$150\,\upmu{\hbox {m}}$$ were tested. The influence of

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-09
Lee J. Mears, Andrew Baldwin, Mohd Y. Ali, Rajan Kumar, Farrukh S. Alvi

Abstract Strong crossflow and swept separation are key aspects of the flow dynamics of 3-D shock wave/boundary layer interactions. This study explores the global surface pressure field beneath the canonical interaction produced by a sharp fin with deflection angle $$15^\circ$$ with a turbulent incoming boundary in a Mach 2 freestream flow. This corresponds to an interaction of moderate strength, and

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-05
S. Amir Bahrani, Nicolas Périnet, Maxime Costalonga, Laurent Royon, Philippe Brunet

Abstract We study the secondary time-averaged flow (streaming) generated by an oscillating cylinder immersed within a fluid, under high amplitude forcing so that inertial effects are significant. This streaming is decomposed into a viscous boundary layer flow where vorticity is created, and an outer flow of larger size. We operate under conditions of relatively low viscosity, so that the boundary layer

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-03
Girish K. Jankee, Bharathram Ganapathisubramani

Abstract Pixel locking in stereoscopic particle image velocimetry (SPIV) is often overlooked, albeit the existence of studies demonstrating an influence on turbulent statistics. Such a bias error occurs when the seeding particles have an image diameter in the range of 1–2 pixels. Together with the advent of superior cameras and more powerful lasers, new image-processing techniques enable large field

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-03
Abhishek Mishra, Harekrishna Yadav, Lyazid Djenidi, Amit Agrawal

Abstract An experimental study has been performed by using particle image velocimetry to investigate the effect of nozzle-to-plate separation distance (L) and jet impingement angle on the flow characteristics of an obliquely inclined submerged water jet. Measurements were taken for L = 1D, 2D, 4D and 6D (where D is the diameter of the nozzle) for the jet impingement angle (θ) of 45° and 26°, and the

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-02
Davide Gatti, Lars von Deyn, Pourya Forooghi, Bettina Frohnapfel

Abstract Trapezoidal riblets are experimentally investigated in both their drag-reducing and drag-increasing regimes in an air turbulent channel flow facility. The nondimensional riblet spacing $$s^+$$ and height $$h^+$$ in viscous units are varied by changing the bulk Reynolds number in the range $$5 \times 10^3<{\mathrm{Re}}_b<8.5 \times 10^4$$. The change in skin-friction drag is accurately measured

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-02
Muchen Xu, Blaine Arihara, Hao Tong, Ning Yu, Yuta Ujiie, Chang-Jin Kim

Abstract Accurate measurement of shear stress on a solid surface is a crucial but challenging task in fluid mechanics. Different sensors are usually used for different experimental settings: water channel, wind tunnel, towing tank, watercraft, aircraft, etc. This paper presents a direct shear sensor designed to work for varying test objects and flow conditions. Designed to compare two different sample

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-02
H. Mirsandi, W. J. Smit, G. Kong, M. W. Baltussen, E. A. J. F. Peters, J. A. M. Kuipers

Abstract The formation of gas bubbles by submerged orifices is a fundamental process encountered in various industrial applications. The dynamics of the contact line and the contact angle may have a significant influence on the detached bubble size depending on the wettability of the system. In this study, the influence of wetting conditions on the dynamics of bubble formation from a submerged orifice

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-02
Liang Qin, Yang Xiang, Haiyan Lin, Hong Liu

Abstract Particle image velocimetry experiments were carried out to investigate the formation and dynamics of compressible vortex rings (CVRs) generated by a shock tube apparatus. Five shock Mach numbers ($$M_\mathrm{s}$$) including $$M_\mathrm{s}=\,1.28$$, 1.39, 1.48, 1.56, and 1.59 are designed to generate the three typical CVRs including shock-free CVRs, CVRs with embedded shock, and CVRs with embedded

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-02
J. Lunte, E. Schülein

Abstract Wall shear stress and wall streamline direction measurements were conducted on a generic delta wing model to demonstrate the potential of the white-light oil-film interferometry in three-dimensional flows. With the proposed algorithm, an automatic oil-film thickness calculation is possible and yields reproducible and plausible wall shear stress distributions on the leeward side of the delta

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-02
David MacLucas, Beric Skews, Harald Kleine

Abstract The interaction of a plane shock wave in air with concave profiles has been used in the past mainly to understand the nature of shock wave focusing. The current study examines the complex two-dimensional flow field resulting from the interaction of a plane shock wave entering a symmetrical cavity with curved walls. Of particular interest are the development of reflection patterns of the incident

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2020-03-02
Samuel J. Grauer, Adam M. Steinberg

Abstract We propose a novel approach to background-oriented schlieren (BOS) tomography (BOST) that unifies the deflection sensing and reconstruction algorithms. BOS is a 2D flow visualization technique that renders light deflections due to refraction in the fluid. Simultaneous BOS measurements from unique views can be reconstructed by tomography to estimate the fluid’s 3D refractive index field. The

更新日期：2020-03-20
• Exp. Fluids (IF 2.443) Pub Date : 2019-11-28
Felix Greiffenhagen,Jakob Woisetschläger,Johannes Gürtler,Jürgen Czarske

Abstract Modern, lean and premixed gas turbine combustion concepts for low NOx emissions are prone to combustion instabilities. In a previous work it was shown that laser interferometric vibrometry (LIV) can be used to record global as well as local heat release fluctuations in swirl-stabilized premixed methane flames quantitatively, if other effects influencing density are small. In this work a newly

更新日期：2019-11-28
• Exp. Fluids (IF 2.443) Pub Date : 2019-11-21
Melissa C Brindise,Margaret M Busse,Pavlos P Vlachos

Optical imaging is commonly used to investigate biological flows and cardiovascular disease using compliant silicone polydimethysiloxane (PDMS) Sylgard 184 geometries. However, selecting the working fluid with blood density and viscosity, and PDMS index of refraction (RI) for such experiments is challenging. Currently, water-glycerol is commonly used and sodium iodide (NaI) often added to increase

更新日期：2019-11-01
• Exp. Fluids (IF 2.443) Pub Date : 2019-03-19
J W Van der Kindere,A Laskari,B Ganapathisubramani,R de Kat

Abstract In this study, we quantify the accuracy of a simple pressure estimation method from 2D snapshot PIV in attached and separated flows. Particle image velocimetry (PIV) offers the possibility to acquire a field of pressure instead of point measurements. Multiple methods may be used to obtain pressure from PIV measurements, however, the current state-of-the-art requires expensive equipment and

更新日期：2019-11-01
• Exp. Fluids (IF 2.443) Pub Date : 2014-07-30

The aortic sinus vortex is a classical flow structure of significant importance to aortic valve dynamics and the initiation and progression of calific aortic valve disease. We characterize the spatio-temporal characteristics of aortic sinus voxtex dynamics in relation to the viscosity of blood analog solution as well as heart rate. High resolution time-resolved (2KHz) particle image velocimetry was

更新日期：2019-11-01
• Exp. Fluids (IF 2.443) Pub Date : 2012-01-01
Matteo Novara,Fulvio Scarano

The motion tracking enhancement technique (MTE) is a recently introduced method to improve the accuracy of tomographic PIV measurements at seeding density higher than currently practiced. The working principle is based on the fact that the particle field and its projections are correlated between the two exposures. Therefore, information from subsequent exposures can be shared within the tomographic

更新日期：2019-11-01
• Exp. Fluids (IF 2.443) Pub Date : 2012-01-01
Fulvio Scarano,Peter Moore

A numerical implementation of the advection equation is proposed to increase the temporal resolution of PIV time series. The method is based on the principle that velocity fluctuations are transported passively, similar to Taylor's hypothesis of frozen turbulence. In the present work, the advection model is extended to unsteady three-dimensional flows. The main objective of the method is that of lowering

更新日期：2019-11-01
• Exp. Fluids (IF 2.443) Pub Date : 2011-11-01
In Mei Sou,John S Allen,Christopher N Layman,Chittaranjan Ray

Subsurface coherent structures and surface temperatures are investigated using simultaneous measurements of particle image velocimetry (PIV) and infrared (IR) thermography. Results for coherent structures from acoustic streaming and associated heating transfer in a rectangular tank with an acoustic horn mounted horizontally at the sidewall are presented. An observed vortex pair develops and propagates

更新日期：2019-11-01
• Exp. Fluids (IF 2.443) Pub Date : 2011-05-01
Damien Garcia

Post-processing of PIV (particle image velocimetry) data typically contains three following stages: validation of the raw data, replacement of spurious and missing vectors, and some smoothing. A robust post-processing technique that carries out these steps simultaneously is proposed. The new all-in-one method (DCT-PLS), based on a penalized least squares approach (PLS), combines the use of the discrete

更新日期：2019-11-01
• Exp. Fluids (IF 2.443) Pub Date : 2009-08-01
Eiichiro Yamaguchi,Bradford J Smith,Donald P Gaver

Microscale particle image velocimetry (μ-PIV) measurements of ensemble flow fields surrounding a steadily-migrating semi-infinite bubble through the novel adaptation of a computer controlled linear motor flow control system. The system was programmed to generate a square wave velocity input in order to produce accurate constant bubble propagation repeatedly and effectively through a fused glass capillary

更新日期：2019-11-01
• Exp. Fluids (IF 2.443) Pub Date : 2009-05-01
James R Usherwood

The aerodynamic forces acting on a revolving dried pigeon wing and a flat card replica were measured with a propeller rig, effectively simulating a wing in continual downstroke. Two methods were adopted: direct measurement of the reaction vertical force and torque via a forceplate, and a map of the pressures along and across the wing measured with differential pressure sensors. Wings were tested at

更新日期：2019-11-01
• Exp. Fluids (IF 2.443) Pub Date : 2008-12-01
David H Frakes,Kerem Pekkan,Lakshmi P Dasi,Hiroumi D Kitajima,Diane de Zelicourt,Hwa Liang Leo,Josie Carberry,Kartik Sundareswaran,Helene Simon,Ajit P Yoganathan

Complex applications in fluid dynamics research often require more highly resolved velocity data than direct measurements or simulations provide. The advent of stereo PIV and PCMR techniques has advanced the state-of-the-art in flow velocity measurement, but 3D spatial resolution remains limited. Here a new technique is proposed for velocity data interpolation to address this problem. The new method

更新日期：2019-11-01
• Exp. Fluids (IF 2.443) Pub Date : 2008-09-01
James H J Buchholz,Richard P Clark,Alexander J Smits

An apparatus is described for the measurement of unsteady thrust and propulsive efficiency produced by biologically inspired oscillating hydrodynamic propulsors. Force measurement is achieved using a strain-gauge-based force transducer, augmented with a lever to amplify or attenuate the applied force and control the measurement sensitivity and natural frequency of vibration. The lever can be used to

更新日期：2019-11-01
• Exp. Fluids (IF 2.443) Pub Date : 2007-11-01
Marcus Hultmark,Megan Leftwich,Alexander J Smits

Experiments are reported on the hydrodynamics of a swimming robotic lamprey under conditions of steady swimming and where the thrust exceeds the drag. The motion of the robot was based on the swimming of live lampreys, which is described by an equation similar to that developed for the American eel by Tytell and Lauder (J Exp Biol 207:1825-1841, 2004). For steady swimming, the wake structure closely

更新日期：2019-11-01
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