Plenary Award Lectures

  • Leonard da Vinci Award

Prof. Koji Okamoto
 Nuclear Professional School, The University of Tokyo, Japan

 

Title: "Dynamic Quantitative Visualization"...... In Memorial to Prof. Yasuki Nakayama

In 2002, CMOS high-speed camera with 2kfps, 1Mpixel, opened the Dynamic Quantitative Visualization era. Now, we can measure the fields' information under high-temporal and high-spatial resolution. With reviewing the past 15 years development, the next 10 years revolution on flow visualization will be discussed.

 

 

  • Asanuma Award

Prof. Oleg Penyazkov
 Dep. of Physics and Chemistry of Nonequilibrium Media, A.V. Luikov Heat and Mass Transfer Institute, Minsk, Belarus

Title: Flow Visualization in Experimental High-Temperature Gas Dynamics

Qualitative and quantitative visualization techniques aimed to understanding experimental flow conditions in different high-temperature gasdynamic facilities are considered for reacting and non-reacting flow measurements. The collection of shadow, schlieren, interferometric, and self-luminous observations are presented for shock and detonation tubes, as well as for jets, combustion bombs, rapid compressed machines, low-and high-temperature plasma devices. Advantages and limitations on each of the methods are discussed, considering their efficiency, limitations, and ability to be combined with local flow measurements.

 

 

Keynote lectures

[KL01]

  • Jeffrey S. AllenDepartment of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, MI, USA

Title: Using High Speed, Reflective-Mode Confocal Microscopy to Observe and Measure Liquid Film Dynamics in Microchannel Two-Phase Flow

Optical microscopy has long provided a window into microscale thermal and fluid phenomena. Underlying microscopic optical imaging is the requirement that the illumination path be orthogonal to the viewing direction.  Various methods are used to ensure this requirement; methods such as matching refractive indices and epi-illumination. The presence of a gas-liquid interface in the optical path often results in distortion and diffraction that has frustrated quantitative measurements of multiphase flow in microsystems. A novel confocal system has been developed that allows for high speed optical slicing in regions not typically accessible to microscopy.  A swept-field confocal system has been modified to function in either fluorescence or reflective modes. The current system can optically slice at thicknesses as thin as 2 micrometers up to 500 frames per second. Liquid film thickness, interface shape, and particle velocimetry can be captured simultaneously near moving menisci and in high speed gas-liquid microchannel flows. The high-speed, reflective-mode confocal system will be discussed. In addition, the presentation will discuss the existence of a shock formation in thin liquid films in non-wetting microchannels will be examined. Confocal images simultaneously provide meniscus velocity, contact line and shock front along with velocities in the thin liquid film via particle tracking velocimetry.

    [KL02]
  • James T. Heineck, NASA Ames Research Center, Moffet Field, California, USA
  • Daniel W. Banks, NASA Armstrong Flight Research Center, Edwards, California, USA

Title:  Air-to-Air Background Oriented Schlieren

Air-to-air background oriented schlieren, or AirBOS, was developed to obtain high spatial resolution schlieren images of full-scale aircraft in supersonic flight.  The basis of the current technique utilizes a slow moving sensor aircraft outfitted with nadir view port mounted cameras, a supersonic aircraft passing beneath the sensor aircraft, and a desert floor as the speckle background. Image processing is more complex as compared to an equivalent static background BOS application.  This is due to the relative movement of the background caused by movements of the sensor aircraft and target aircraft.  This presentation will describe the system, flight planning, processing, and show results.

    [KL03]
  • Han-Sheung ChuangDepartment of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan

 

Title:  Turning Brownian Motion from Noise to Signal: An Example of Rapid Anti-Microbial Susceptibility Testing by Diffusometric Immunosensing

Brownian motion has long been known as random noise. However, taking advantage of the Einstein relation, the particle diameter can be related to the diffusivity change. Optical diffusometry is used to detect the existence of microorganisms in this study. By mixing target bacteria, P. aeruginosa or S. aureus, with functionalized particles, the Brownian motion will be altered accordingly. The corresponding particle diffusivity can then serve as an indicator in relation to the concentration of the bacteria. The technique requires neither complicated fabrication nor sophisticated instruments. A limit of detection (LOD) as low as one bacterium was achieved. The result was further used to improve the anti-microbial susceptibility testing (AST). At last, the turnaround time for each AST measurement was successfully reduced from days to hours (~2 h) based on the proposed method. (MOST grant # 104-2221-E-006 -093 -MY3)

    [KL04]
  • Andrea IaniroBioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain

 

Title:  Advanced Techniques for the Investigation of Flow Field and Heat Transfer in impinging Jets

The complex flow structures of jets impinging at relatively short nozzle-to-plate distance motivated a huge number of studies in order to allow for the understanding of their thermo-fluid-dynamic features. The lecture will discuss some open points in the subject and the application of two relevant techniques of modern experimental thermo-fluids, namely infrared thermography and tomographic PIV. Tomographic PIV, if time resolved, allows to obtain fully 4D flow field information. The capabilities of IR thermography, well assessed for providing 2D maps of surface heat transfer distribution, are here pushed in the direction of obtaining information about the temporal variation of unsteady heat fluxes. The outcomes of the visualization and measurement capabilities of these techniques are discussed also in view of developing low order models via modal decomposition.

    [KL05]
  • Sukho Chung,  King Abdullah University of Science and Technology (KAUST), Saudi Arabia

 

Title:  Fuel density and electric field effects on small coflow flames

Flow characteristics in small coflow diffusion flames were investigated by adopting various laser diagnostic techniques including Mie scattering, PIV and PLIF. The buoyancy force exerted on fuel as well as on burnt gas significantly distorted near nozzle flow fields. For fuels with densities heavier than air, recirculation zones were formed close to the nozzle. When AC electric field was applied, the flow field drastically altered, leading to the formation of toroidal vortices near the nozzle rim. AC driven instabilities, such as an oscillation, pinch-off and spinning of flames were identified.

    [KL06]
  • Tomasz A. KowalewskiInstitute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland

 

Title: Experimental Challenges of Nano and Microfluidics  

Contemporary experiment in fluid mechanics evidently moves from large scale problems to micro or even nanoscale phenomena, to accomplish our desire to elucidate mechanisms driving living nature.  Visualization methods at such scales found new exciting approaches, some of them touching molecular limits, where assumption of continuous and deterministic description becomes questionable. At short time and length scales diffusion governed by Brownian motion becomes the most efficient transport mechanism. Whereas its analysis is apparently simple in case of ideal spherical objects, understanding complex behavior of long, deformable objects is far from being complete. Examples of experimental techniques allowing us to monitor and control behavior of single micro objects conveyed by flow will be given (NCN grant 2011/03/B/ST8/05481).

    [KL07]
  • Sang Joon LeeDepartment of Mechanical Engineering, POSTECH, Pohang, Korea

 

Title: Quantitative Visualization of Various Biofluid Flow Phenomena in Nature

Biological flows are vital for the conservation of life and indispensable commodity of living organisms. Morphological structures of living organisms and biological flow phenomena in nature have been evolved through long history. The basic biophysics of several biofluid flow phenomena were investigated experimentally using advanced flow visualization techniques, such as X-ray PIV, holographic PTV, and ultrasound speckle image velocimetry. The biological flows handled in this talk include liquid sucking phenomena of mosquitoes and butterflies, and sap flows in xylem vessels of vascular plants. Detailed understanding on these biofluid flow phenomena would be used to develop creative biomimetic technologies for practical applications in biomedical science, microfluidics and renewable energy.

    [KL08]
  • Friedrich LeopoldFrench-German Research Institute of Saint-Louis (ISL), Saint-Louis, France
  • Maranori OtaFrench-German Research Institute of Saint-Louis (ISL), Saint-Louis, France


 

Title: Reconstruction of unsteady flows using the Colored Background Oriented Schlieren technique

 In this presentation the improved Background Oriented Schlieren technique called CBOS (Colored Background Oriented Schlieren) is described and used to reconstruct the density fields of three-dimensional flows. The Background Oriented Schlieren technique (BOS) allows the measurement of the light deflection caused by density gradients in a compressible flow. For this purpose the distortion of the image of a background pattern observed through the flow is used. In order to increase the performance of the conventional Background Oriented Schlieren technique, the monochromatic background is replaced by a colored dot pattern. The different colors are treated separately using suitable correlation algorithms. Therefore, the precision and the spatial resolution can be highly increased. Furthermore a special arrangement of the different colored dot patterns in the background allows astigmatism in the region with high density gradients to be overcome. For the first time an algebraic reconstruction technique (ART) is then used to reconstruct the density field of unsteady flows around a spike-tipped model from CBOS measurements. The obtained images reveal the interaction between the free-stream flow and the high-pressure region in front of the model, which leads to large-scale instabilities in the flow.

    [KL09]
  • Yingzheng LiuSchool of Mechanical Engineering, Shanghai Jiao Tong University, China

 


Title:
Wake dynamics behind bio-inspired cylindrical structures: POD and DMD analysis

Wake dynamics behind two bio-inspired cylindrical structures with capability of VIV suppression are given, i.e., a cactus-shaped cylinder, and a seal-vibrissa-shaped cylinder. In the cactus-shaped cylinder system, influences of the V-shaped grooves and spines on the wake are visualized by using TR-PIV. In the seal-vibrissa-shaped cylinder system, the lift / drag coefficients, and statistical quantities of the wake flow are compared with a smooth circular cylinder, an elliptical cylinder, and a wavy cylinder. Subsequently, PIV measurements in combination with POD and DMD analysis are made of the seal-vibrissa-shaped cylinder, showing a three-dimensional view of the unique unsteady behaviors in the near wake.

    [KL10]
  • Nenad Miljkovic,  Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, IL, USA
  • Evelyn N. Wang,  Department of Mechanical Engineering, MIT, MA, USA

 

 

Title: Droplet Visualizations on Nanoengineered Surfaces for Enhanced Energy Transfer

 

Nanoengineered surfaces offer new possibilities to manipulate fluidic and thermal transport processes for a variety of applications. In this talk, we will discuss fundamental studies and visualizations of droplet behavior on nanoengineered superhydrophobic surfaces, and the effect of manipulating these fluid-structure interactions for heat transfer, anti-icing, and self-cleaning applications. We elucidated the importance of structure geometry on droplet morphology, as well as growth and departure dynamics.  Furthermore, using high speed imaging with a novel focal-plane-shifting visualization technique, we have unveiled the key factors governing microscale droplet coalescence dynamics, droplet-surface adhesion, and departure directionality. Our studies provide key insights underlying the complex fluid-structure interactions for energy and momentum transfer enhancement and also offer a path to achieving increased efficiency in next generation energy systems.

    [KL11]
  • V. E. MosharovCentral Aero-Hydrodynamic Institute (TsAGI), Zhukovsky, Moscow reg., Russia

 


Title:
Surface flow visualization in large wind TUNNELs

The lecture presents methods of surface flow visualization are used in large transonic wind tunnel T-128. Pressure Sensitive Paint method yields pressure distribution on 3D model mesh and can be used for local loads calculation. Paint formulation includes two luminophors: sensitive and reference. Reference luminophor is used for pixel-by-pixel correction of excitation light intensity variations during the test. Shear stress sensitive Liquid Crystals are the best method to study a boundary layer transition on the metal models. Particle Image Surface Flow Visualization method yields surface streamlines. Model is covered by viscous oil containing luminescent particles. Images of the particle distribution on the model surface are processed similar to PIV method.

 
    [KL12]
  • Nao NinomiyaDepartment of Optical Engineering, Utsunomiya University, Japan

 


Title:
Three-Dimensional Velocity Measurement by a Single Camera Observation using Digital Holography

Digital holography can capture the three-dimensional feature of an object.  But, it has been known that the resolution in the depth direction is very poor for the commonly used in-line holography.  Presently, the Doppler phase-shifting holography has been used for the three-dimensional measurement of dispersed objects.  This method extracts the signal of a fixed frequency caused by the Doppler beat between the object light and the reference light.  Thus, the longitudinal velocity of an object can be measured by the beat frequency.  At the same time, transverse velocities can also be measured by the ordinary PIV algorithm.

    [KL13]
  • Koichi NichinoDepartment of Mechanical Engineering, Yokohama National University, Japan

 

Title: Whole flow field measurement for the study of instability mechanisms of thermocapillary convection in microgravity experiments

Whole flow field measurement based on flow visualization and quantitative image data analysis has been exploited for the study of instability mechanisms of thermocapillary convection in large-scale liquid bridges formed in long-duration microgravity experiments on the International Space Station. All apparatuses on ISS were remotely controlled from the space center at Tsukuba, Japan. Three-dimensional particle tracking velocimetry with modified trajectory tracking algorithm was used to capture 3-D flow structures associated with propagation of hydrothermal waves. More detailed 3-D flow structures were extracted by applying a tomographic PIV technique to the particle images. The results obtained were compared with those predicted from the linear stability analysis and discussed in light of the effect of interfacial heat transfer on the instability mechanisms.

    [KL14]
  • Michael G. OlsenDepartment of Mechanical Engineering, Iowa State University, USA

Title: Flow Visualization and Measurement in Microscale and Macroscale Vortex Nanoprecipitation Reactors

Flash NanoPrecipitation (FNP) is a technique for manufacturing monodisperse functional nanoparticles. FNP has primarily been demonstrated in microscale mixing devices, and one promising reactor is the microscale Multi-Inlet Vortex Mixer (MIVM) in which tangential inlet streams mix and react in a cylindrical reactor.  Experiments were performed in the MIVM consisting of both confocal laser induced fluorescence and microscopic PIV measurements.  Because the small dimensions and small throughput of the microscale MIVM limits it to producing functional nanoparticles in small batch sizes, the feasibility of scaling up the FNP process to a macroscale MIVM capable of generating large quantities of functional nanoparticles has been investigated using both stereo PIV and PLIF.  Dynamic delayed detached eddy simulations were also performed and compared with the experimental results.

    [KL15]
  • Jun SakakibaraDepartment of Mechanical Engineering, Meiji University, Japan

 

Title: Visualization of Flow in Eye

The posterior chamber of the eye, which is a gap between the cornea and lens, is filled with water. This water is usually stationary, but may undergo rapid flow during cataract surgery, an operation to replace an opaque lens with an artificial lens. The interior surface of the cornea may consequently be influenced by the applied fluid forces. We measured velocity distribution of such a flow field simulated in a pig’s eye using stereo PIV, and estimated shear stress. In addition to the fluid forces, the cornea may be damaged by debris from the lens traveling through the gap. A specular microscope was used to visualize the alteration of cornea endothelial cells hit by debris.

    [KL16]
  • Andy Sarles Mechanical Engineering, University of Tennessee, USA

Title: Biomimetic membranes at liquid interfaces:  a path toward cell-inspired materials

In recent years there has been significant interest in using biological molecules, including functional proteins and peptides, for developing novel engineered materials and systems inspired by the diverse functionalities of cellular membranes in living organisms. We have developed fluidic techniques to assemble synthetic cell membranes at liquid interfaces using aqueous microdroplets in oil, and we employ experimental methods including imaging and electrical recordings to quantify the structural and transport properties of these nanometer-thick films. This work forms the basis for a new class of multifunctional soft material that mimics the compartmentalization of living cells.

    [KL17]
  • Fulvio ScaranoAerospace Engineering Department, TU Delft, Delft, The Netherlands

 

Title: The expanding dimensions of Particle Image Velocimetry

Particle Image Velocimetry embeds the power of visualization and the rigour of quantitative measurements. The current state-of-the-art features three-dimensional and time-resolved measurements (4D) for a better understanding of complex and turbulent flows. The availability of 4D data not only allows the study of vortex topology and its dynamics such as in jets, wakes or boundary layers. The measurements envelope is now expanding towards the pressure field, inferred with the use the flow governing equations. The lecture will finally survey the exciting developments of 4D-PIV in wind tunnels using sub-millimetre Helium-filled soap bubbles. These large scale experiments are at a time bringing the PIV technique closer to the needs of industrial applications and inspire students with a powerful flow visualization experience.

    [KL18]
  • Andreas SchroderGerman Aerospace Center, Institute of Aerodynamics and Flow Technology, Göttingen, Germany

 

Title: Shake-The-Box: 3D Lagrangian tracking for turbulence characterization at high particle image densities   

Shake-The-Box (STB) is a novel time-resolved 3D Lagrangian particle tracking method for densely seeded flows. The STB algorithm has been developed at DLR Göttingen in the past two years and uses the prediction of 3D particle distributions for each subsequent time-step as a mean to seize the temporal domain for accurate track reconstructions based on time series of particle images from few camera projections. Exploiting the temporal information enables the processing of densely seeded flows (up to and beyond 0.1 particles per pixel with a nearly complete suppression of ghost particles). From resulting 3D acceleration fields the unsteady 3D pressure distributions can be calculated.The STB method has been applied to wall bounded turbulence in air and water and to a m³-scale experiment using Helium–Filled-Soap-Bubbles (HFSB) as tracers. The results demonstrate that with STB valuable data for turbulence characterization with outstanding temporal and spatial resolution especially in (wall bounded) shear flow can be obtained.

 

    [KL19]
  • Gary SettlesMechanical and Nuclear Engineering, Pennsylvania State University, USA

Title: Recent development in schlieren and shadowgraph techniques 

The most important development in schlieren and shadowgraph techniques in the last 15 years is BOS, which requires computer processing of images pairs. But high-speed digital cameras and the ready availability of customized image processing, especially using MATLAB, also provides velocimetry of turbulent refractive flows, pseudo-streak imaging of time-dependent phenomena, and other quantitative applications of these formerly-qualitative visualization methods.  Examples include optical flow algorithms applied to BOS and to the velocimetry of turbulent jets, pseudo-streak imaging of explosions, digital color schlieren, and the rendering of CFD results as gradient and Laplacian images: computed schlieren and shadowgraphy.

    [KL20]
  • Friedrich SeilerInstitute for Fluid Mechanics, University of Karlsruhe, Germany


Title:
Mach waves occuring over a backward facing edge in supersonic flow 

At the University of New South Wales, Australia, the supersonic flow over a cavity was investigated in a wind tunnel at Mach numbers 2 and 3. High-speed schlieren visualizations show that the incoming boundary layer separates and forms a shear layer over the cavity. This shear layer emits Mach waves into the cavity and the free stream. A theory recently developed for describing the Mach wave dynamics from supersonic jets is applied for calculating the Mach waves occurring over and within the cavity flow. In addition, numerical LES-calculations are performed for comparison at the French-German Research Institute of Saint-Louis, France.

    [KL21]
  • Beric W. SkewsUniversity of the Witwatersrand, Johannesburg, South Africa

 


Title:
Shock wave flows using symmetry   

 

The use of a symmetry plane, such as to study shock wave reflection between two wedges, is common, and can be extended to more complex studies of steady and unsteady flows. Issues such as the effect of aspect ratio, dynamic pitch, and the influence of body shape and curvature, are pertinent. In the unsteady case, use of symmetry can remove the effects of a boundary layer, extend diffraction studies beyond two-dimensions, study focussing effects in a cavity, and effectively increase the apparent height of a test channel. The case of axisymmetric flow is more common and some unusual cases will also be illustrated.

     [KL22]
  • Hyung Jin SungKAIST, Deajeon, Korea

 


Title:
Acousto-thermo-microfluidics   

The interaction of external fields with the microfluids have been advantageous. We have been studying the interaction of acoustic waves with fluids at the microscale, and have demonstrated potential to efficiently handle suspended micro-objects. The surface acoustic waves (SAWs) are produced on a piezoelectric substrate using an interdigitated transducer. The SAWs have been used to separate particles of different sizes and mix fluids at desired concentration. Recently, the SAWs have been used to interact with a polymer material to realize an acoutothermal mircoheater. The microheater is used to demonstrate fast DNA amplification (rapid thermal cycles in PCR) and one-shot DNA melting-curve analysis. A thermochromic display has also been realized using the acoustothermal heating mechanism.

    [KL23]
  • Jinjun WangKey Laboratory of Fluid Mechanics, Beijing University of Aeronautics and Astronautics, China

Title: Vortex Induced Laminar Boundary Layer Transition on a Flat Plate with Zero-Pressure Gradient

The influence of a circular cylinder wake on a zero-pressure-gradient flat plate laminar boundary layer is experimentally investigated using hydrogen bubble visualization and particle image velocimetry technique. A different bypass transition route from the Klebanoff mode is revealed. This transition scenario is mainly characterized with the generation of secondary transverse vortical structures near the flat plate surface and its evolution. Lagrangian coherent structures (LCS) are revealed quantitatively with finite time Lyapunov exponents (FTLE) fields derived from the PIV data. The boundary layer bypass transition control using synthetic jet at the rear stagnation point of the cylinder is explored, and an attempt is made to explain the mechanism of the control.

    [KL24]
  • Steve WereleyMechanical Engineering, Purdue University, USA

 

Title: Visualizing Microscale Electrothermal Vortices

The field of electrokinetics has seen tremendous growth in recent years due to developments in fabricating micro and nanoscale devices as well as improvements in qualitative flow visualization and quantitative flow measurement.  This talk will cross-cut through several projects in my research group to discuss the visualization and measurement approaches in electrothermally-driven vortices.  These vortices are driven by the interaction of a temperature gradient in the fluid and an electric field.  Because they are 3D vortices and observation is typically performed with a single line of sight, flow behavior can be difficult to infer.  We have pioneered several approaches to visualizing and measuring such flows including 3D Micro-PIV as well as optical flow sectioning along lines of symmetry.

    [KL25]
  • Corey WilsonCollege of Marine Engineering, Dalian Maritime University, Dalian, China
  • Hongbin MaDepartment of Mechanical & Aerospace Engineering, University of Missouri, MO, USA

 

Title: Neutron radiography for observation of oscillating heat pipes

 

The fluid dynamics of an oscillating heat pipe are difficult to observe due to the metallic envelope used in its construction.  Observation of the flow typically requires glass or plastic windows, however this alters the contact angle, wetting characteristics, and thermal characteristics of the flow.  Due to the chaotic nature of the flow, these resulting flow patterns can be different than a normal heat pipe.  Neutron radiography was developed as a way to observation of hydrogen rich molecules within metallic envelopes.  Utilizing neutron radiography we were able to investigate flow characteristics of a train of liquid plugs and vapor bubbles in capillaries including vapor bubble generation, liquid plug distribution, liquid vapor interface, and frequency and amplitude.  This will significantly help to better understand fluid flow and heat transfer occurring in an oscillating heat pipe and design the highly efficient cooling systems of oscillating heat pipes.

 



ISFV17 Website. Last update: June 15, 2016.