Begell House Inc.
Journal of Flow Visualization and Image Processing
JFV
1065-3090
19
4
2012
REVEALING ASCENDING BUBBLE-DRIVEN FLOW PATTERNS IN A LASER-ETCHED CHAMPAGNE GLASS BY MEANS OF PARTICLE IMAGE VELOCIMETRY (PIV)
279-289
10.1615/JFlowVisImageProc.2013005152
Fabien
Beaumont
Laboratoire de Thermomecanique GRESPI- EA4301, Universite de Reims, 51687 Reims cedex 2, France
Catalin
Popa
Laboratoire de Thermomecanique GRESPI- EA4301, Universite de Reims, 51687 Reims cedex 2, France
Gerard
Liger-Belair
Equipe Effervescence, Champagne et Applications/Groupe de Spectrometrie Moleculaire et Atmospherique UMR-CNRS7331, Universite de Reims, 51687 Reims cedex 2, France
Guillaume
Polidori
Laboratoire de Thermomecanique GRESPI- EA4301, Universite de Reims, 51687 Reims cedex 2, France
PIV
laser tomography
flow patterns
champagne
dissolved CO2
vortex
In this article, the Particle Image Velocimetry (PIV) technique was used in order to determine the velocity field of the ascending bubbles driven flow patterns in a glass being poured with champagne. Bubble nucleation and rise was induced at the bottom of the glass, on its axis of symmetry, from a ring-shaped etching done with adjoining laser beam points of impact. Both the velocity and vorticity fields were found to be in good agreement with previous qualitative flow visualizations as determined by means of laser tomography.
FLOW VISUALIZATION OF NATURAL CONVECTION IN A VERTICAL CHANNEL WITH ANTISYMMETRIC HEATING
291-308
10.1615/JFlowVisImageProc.2013008371
Derek
Roeleveld
Department of Mechanical & Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario, Canada M5B 2K3
David
Naylor
Department of Mechanical & Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario, Canada M5B 2K3
laser interferometry
temperature field visualization
flow field visualization
natural convection
vertical channel
antisymmetric heating
Flow- and temperature-field photographs were obtained for natural convection in a vertical channel with antisymmetric heating. The heating is antisymmetric when the hot wall is heated above the ambient temperature by the same amount that the cold wall is cooled below the ambient, producing equal but opposite buoyancy forces. These opposite buoyancy forces can cause instability inside the channel. So the flow- and temperature fields are of interest for validation of numerical modeling. The flow field was obtained by means of smoke flow visualization using a laser sheet and a Drager tube, which supplied the aerosol. A Mach−Zehnder interferometer was used to obtain the temperature field. Results were obtained over a range of aspect ratios and Rayleigh numbers ranging from a steady laminar to an unsteady turbulent flow.
FLOW VISUALIZATION APPROACH FOR PERIODICALLY REVERSED FLOWS
309-321
10.1615/JFlowVisImageProc.2014006575
Francisco
Botero
Department of Mechanical Engineering, Universidad EAFIT, Cr 49 No 7 sur 50, Medellin, Colombia
Sebastian
Guzman
Department of Mechanical Engineering, Universidad EAFIT, Cr 49 No 7 sur 50, Medellin, Colombia
Vlad
Hasmatuchi
Laboratory for Hydraulic Machines, Ecole Polytechnique Federale de Lausanne, Avenue de Cour 33 bis, CH-1007 Lausanne, Switzerland
Steven
Roth
Laboratory for Hydraulic Machines, Ecole Polytechnique Federale de Lausanne, Avenue de Cour 33 bis, CH-1007 Lausanne, Switzerland
Mohamed
Farhat
Laboratory for Hydraulic Machines, Ecole Polytechnique Federale de Lausanne, Avenue de Cour 33 bis, CH-1007 Lausanne, Switzerland
rotating stall
Francis-type pump-turbine
tuft visualization
An unconventional tuft visualization method, along with an image processing technique adapted to the flow conditions, is proposed and implemented on a reduced-scale model of a Francis-type reversible pump-turbine in three different turbine stages such as turbine mode, runaway mode, and turbine break mode. The main goal of this technique is to visualize the complex flow developed during a rotating stall phenomenon. Fluorescent monofilament wires along with high-speed image processing and pressure sensors were installed in the narrow and vaneless gap between the impeller blades and guide vanes. Pressure fluctuations were analyzed along with tuft visualization to describe the flow with and without a rotating stall. The implemented tuft visualization method gives an adjusted qualitative description of the undergoing phenomena, making different flow behaviors such as backflow, high turbulences, recirculation, etc., evident.
STRUCTURES OF A VISCOUS-WAVE FLOW AROUND A LARGE-DIAMETER CIRCULAR CYLINDER
323-354
10.1615/JFlowVisImageProc.2014010739
Giancarlo
Alfonsi
Fluid Dynamics Laboratory, Universita della Calabria, Via P. Bucci 42b, 87036 Rende (Cosenza), Italy
Agostino
Lauria
Fluid Dynamics Laboratory, Universita della Calabria, Via P. Bucci 42b, 87036 Rende, Cosenza, Italy
Leonardo
Primavera
Fluid Dynamics Laboratory, Universita della Calabria, Via P. Bucci, Cubo 42b, 87036 Rende (Cosenza), Italy
diffraction of water waves
surface-piercing vertical circular cylinder
primitive-variables Navier-Stokes equations
direct numerical simulation
swirling-strength criterion for extraction of vortical structures
An analysis of the phenomenon of diffraction of viscous (water) waves caused by a large-diameter, surface-piercing vertical circular cylinder is performed. The three-dimensional time-dependent Navier−Stokes equations in primitive variables (velocity−pressure formulation) are considered for numerical simulation of the given wave case, and (for the first time at the best of the authors' knowledge) an approach followed is that of the Direct Numerical Simulation (DNS), with no models being used in the calculations for the fluctuating portion of the velocity field. The results obtained in terms of the wave runup and in-line force are compared with those given by the close-form velocity-potential solution for the same wave case and, with those given by the numerical integration of the primitive-variable Euler equations, as well as with data of experimental nature obtained by other authors. For further investigation of the flow fields, the swirling-strength criterion for flow-structure extraction is applied to the computed velocity fields, so unveiling a complex configuration of the viscous-flow structures in the vicinity of the cylinder external wall.
COMBINED SPIV-PLIF AND ORTHOGONAL PLIF MEASUREMENTS: MIXING IN A PULSED JET IN CROSSFLOW
355-382
10.1615/JFlowVisImageProc.2014005042
Lionel
Thomas
Institut Pprime, CNRS. Universite de Poitiers. ENSMA. UPR 3346, Departement Fluides, Thermique, Combustion, Branche Fluides. Axe HydEE, SP2MI Teleport 2, Boulevard Marie et Pierre Curie. BP 30179, F86962 FUTUROSCOPE CHASSENEUIL Cedex
R.
Vernet
Institut Pprime, CNRS. Universite de Poitiers. ENSMA. UPR 3346, Departement Fluides, Thermique, Combustion, Branche Fluides. Axe HydEE, SP2MI Teleport 2, Boulevard Marie et Pierre Curie. BP 30179, F86962 FUTUROSCOPE CHASSENEUIL Cedex
Camilo C. M.
Rindt
Eindhoven University of Technology, Department of Mechanical Engineering, P.O.Box 513, 5600MB Eindhoven, The Netherlands
L.
David
Laboratoire d'Etudes Aerodynamiques (LEA), UMR CNRS 6609, Blv. Marie & Pierre Curie, B.P. 30179, 86962 Futuroscope Chasseneuil Cedex, France
combined measurements
PLIF
SPIV
pulsed jet in cross flow
mixing
A simultaneous SPIV-PLIF measurement in water is used to study a pulsed jet in a crossflow. In the longitudinal plane of symmetry of the flow, the velocity fields are measured using Stereoscopic Particle Image Velocimetry (SPIV) and the concentration fields with Planar Laser Induced Fluorescence (PLIF). At the same time, a PLIF measurement is carried out in an orthogonal plane. To take into account the PLIF error sources (spatio-temporal laser intensity variations and out-of-plane fluorescence due to SPIV particles seeding), a special data processing technique has been developed. It allows the study of mixing at an early stage of the development of a pulsed jet in a crossflow. The studied jet is characterized by the Reynolds number Rej = 500 based on the mean jet velocity Uj = 1.67 cm/s, velocity ratio R = 1, sinusoidal forcing amplitude ratio Aj = 2, and the stroke ratio Sr = 2.23.