Bulletin of the American Physical Society
69th Annual Meeting of the APS Division of Fluid Dynamics
Volume 61, Number 20
Sunday–Tuesday, November 20–22, 2016; Portland, Oregon
Session M31: Experimental Techniques - General |
Hide Abstracts |
Chair: Shahram Pouya, Michigan State University Room: F152 |
Tuesday, November 22, 2016 8:00AM - 8:13AM |
M31.00001: Vorticity Measurement using LG Laser Beams with Orbital Angular Momentum Manoochehr Kooochesfahani, Shahram Pouya, Alireza Safaripour, Anton Ryabtsev, Marcos Dantus We present direct measurement of vorticity in a fluid flow based on angular velocity measurement of microparticles contained in the fluid. The method uses Laguerre-Gaussian (LG) laser beams that possess orbital angular momentum (OAM), a spatial (azimuthal) modulation of the beam phase front, and takes advantage of the rotational Doppler shift from microparticles intersecting the beam focus. Results are shown for the flow field of solid body rotation, where the flow vorticity is known precisely. [Preview Abstract] |
Tuesday, November 22, 2016 8:13AM - 8:26AM |
M31.00002: Viscous Drag Measurements using Three Diagnostics Jonathan Naughton, Eric DeMillard, James Crafton, Jessica Webb The measurement of viscous drag on surfaces is difficult due to the small forces involved compared to the pressure force. In addition, the different diagnostics used for measuring viscous drag often work only under a limited number of conditions. To address this issue, three different approaches for measuring viscous drag were evaluated: oil film interferometry, an integral momentum approach based on velocity profile measurements, and a novel drag balance. Oil film interferometry has been widely used for wall shear stress measurements, but only works on smooth surfaces with the appropriate optical properties. Integral momentum approaches should work on all surfaces, but are limited to two-dimensional flows and require the measurement of detailed velocity profiles. Force balances can also provide measurement on any surface, but are subject to misalignment and pressure gradient errors and provide no information about the flow over the surface. In this study, the three diagnostics were tested over a small region of a plate on which a two-dimensional turbulent boundary layer developed. Measurements were made on both smooth and rough surfaces. The strengths and weaknesses of each of the approaches and the benefits of the combined information they provide are discussed. [Preview Abstract] |
Tuesday, November 22, 2016 8:26AM - 8:39AM |
M31.00003: Inverse method for the instantaneous measure of wall shear rate magnitude and direction using electrodiffusion probes Marc-Etienne Lamarche-Gagnon, Jerome Vetel Several methods can be used when one needs to measure wall shear stress in a fluid flow. Yet, it is known that a precise shear measurement is seldom met, mostly when both time and space resolutions are required. The electrodiffusion method lies on the mass transfer between a redox couple contained in an electrolyte and an electrode flush mounted to a wall. Similarly to the heat transfer measured by a hot wire anemometer, the mass transfer can be related to the fluid's wall shear rate. When coupled with a numerical post-treatment by the so-called \textit{inverse method}, precise instantaneous wall shear rate measurements can be obtained. With further improvements, it has the potential to be effective in highly fluctuating three-dimensional flows.\\ We present developments of the inverse method to two-component shear rate measurements, that is shear magnitude and direction. This is achieved with the use of a three-segment electrodiffusion probe. Validation tests of the inverse method are performed in an oscillating plane Poiseuille flow at moderate pulse frequencies, which also includes reverse flow phases, and in the vicinity of a separation point where the wall shear stress experiences local inversion in a controlled separated flow. [Preview Abstract] |
Tuesday, November 22, 2016 8:39AM - 8:52AM |
M31.00004: Using Magnetic Resonance Imaging (MRI) to Investigate Scalar Contaminant Dispersion in an Urban Environment Joseph Cymerman Research in the past few decades on the dispersion of a scalar contaminant through an urban environment, with testing occurring in multiple cities worldwide, has mostly relied on point measurement systems. These models, which are strongly affected by the orientation of the buildings and environmental conditions, obtain relatively few data points and fail to achieve a robust understanding of the complex flow fields from an experimental perspective. A time-averaged MRI-based experimental measurement of the complete three-dimensional flow field has analyzed an array of buildings at two orientations in fully turbulent flow. The Reynolds number and upstream development match a series of tests conducted by both the ARL Atmospheric Sciences Branch and the Los Alamos National Laboratory for comparison, with several million measurements of each of the three components of the mean velocity across the full field. The water-based experimental measurements allow for the assessment of the geometric dispersion of the streamlines and a comparison with several computational models as a means of validation. [Preview Abstract] |
Tuesday, November 22, 2016 8:52AM - 9:05AM |
M31.00005: Characterization of a custom-built RF coil for a high-resolution phase-contrast magnetic resonance velocimeter Byungkuen Yang, Jee-Hyun Cho, Simon Song For the use of clinical purpose magnetic resonance velocimeter (MRV) is a versatile flow visualization technique in that it allows opaque flow, complex geometry, no use of tracer particles and facile fast non-invasive measurements of 3 dimensional and 3 component velocity vectors. However, the spatial resolution of a commercial MR machine is lower than optics-based techniques like PIV. On the other hand, the use of MRV for clinical purposes like cardiovascular flow visualization requires accurate measurements or estimations on wall shear stress (WSS) with a high spatial resolution. We developed a custom-built solenoid RF coil for phase-contrast (PC) MRV to improve its resolution. We compared signal-to-noise ratio, WSS estimations, partial volume effects near wall between the custom RF coil and a commercial coil. Also, a Hagen-Poiseuille flow was analyzed with the custom RF coil. [Preview Abstract] |
Tuesday, November 22, 2016 9:05AM - 9:18AM |
M31.00006: Visualization of vacuum cleaner-induced flow in a carpet by using magnetic resonance velocimetry Jeesoo Lee, Simon Song Understanding characteristics of in-carpet flow induced by a vacuum cleaner nozzle is important to improve the design and performance of the cleaner nozzle. However, optical visualization techniques like PIV are limited to uncover the flow details because a carpet is opaque porous media. We have visualized a mean flow field in a cut-pile type carpet by magnetic resonance velocimetry. The flow was generated by a static vacuum cleaner nozzle, and the working fluid is a copper sulfate aqueous solution. Three dimensional, three component velocity vectors were obtained in a measurement domain of 336 x 128 x 14 mm3 covering the entire nozzle span and a 7-mm thick carpet below the nozzle. The voxel size was 1 x 1 x 0.5 (depthwise) mm3. Based on the visualization data, the permeability, the Forchheimer coefficient and pressure distribution were calculated for the carpet. [Preview Abstract] |
Tuesday, November 22, 2016 9:18AM - 9:31AM |
M31.00007: An experimental validation of the influence of flow profiles and stratified two-phase flow to Lorentz force velocimetry for weakly conducting fluids Andreas Wiederhold, Reschad Ebert, Christian Resagk We report about the feasibility of Lorentz force velocimetry (LFV) for various flow profiles. LFV is a contactless non-invasive technique to measure flow velocity and has been developed in the last years in our institute. This method is advantageous if the fluid is hot, aggressive or opaque like glass melts or liquid metal flows. The conducted experiments shall prove an increased versatility for industrial applications of this method. For the force measurement we use an electromagnetic force compensation balance. As electrolyte salty water is used with an electrical conductivity in the range of 0.035 which corresponds to tap water up to 20 Sm$^{-1}$. Because the conductivity is six orders less than that of liquid metals, here the challenging bottleneck is the resolution of the measurement system. The results show only a slight influence in the force signal at symmetric and strongly asymmetric flow profiles. Furthermore we report about the application of LFV to stratified two-phase flows. We show that it is possible to detect interface instabilities, which is important for the dimensioning of liquid metal batteries. [Preview Abstract] |
Tuesday, November 22, 2016 9:31AM - 9:44AM |
M31.00008: Rheoscopic Fluids in a Post-Kalliroscope World Daniel Borrero-Echeverry, Christopher J. Crowley In rheoscopic flow visualization the working fluid is seeded with small plate-shaped particles, which preferentially align in the flow due to their anisotropy. This leads to preferential light scattering, which highlights qualitatively different regions of the flow. For the past four decades, the gold standard in rheoscopic flow visualization has been Kalliroscope, a commercial product consisting of crystalline guanine particles. Guanine is a shiny compound extracted from fish scales and has traditionally been used in cosmetics to provide a pearlescent effect. It stands out among other options for rheoscopic flow visualization (e.g., aluminum flakes or coated mica particles) due to its relatively good density match with water. Guanine extraction, however, is an expensive process and as the cosmetics industry has adopted less expensive alternatives, commercial guanine production has dropped, leading to the closure of the Kalliroscope Corporation in 2014. In this talk, we discuss our recent discovery of a rheoscopic fluid based on stearic acid crystals, which has an overall performance similar to, and in some cases superior to, Kalliroscope. This rheoscopic fluid can be extracted from household items making it very inexpensive and readily accessible to researchers around the world. [Preview Abstract] |
Tuesday, November 22, 2016 9:44AM - 9:57AM |
M31.00009: Modeling Shock Train Leading Edge Detection in Dual-Mode Scramjets Foluso Ladeinde, Zhipeng Lou, Wenhai Li The objective of this study is to accurately model the detection of shock train leading edge (STLE) in dual-mode scramjet (DMSJ) engines intended for hypersonic flight in air-breathing propulsion systems. The associated vehicles have applications in military warfare and intelligence, and there is commercial interest as well. Shock trains are of interest because they play a significant role in the inability of a DMSJ engine to develop the required propulsive force. The experimental approach to STLE detection has received some attention; as have numerical calculations. However, virtually all of the numerical work focus on mechanically- (i.e., pressure-) generated shock trains, which are much easier to model relative to the phenomenon in the real system where the shock trains are generated by combustion. A focus on combustion, as in the present studies, enables the investigation of the effects of equivalence ratio, which, together with the Mach number, constitutes an important parameter determining mode transition. The various numerical approaches implemented in our work will be reported, with result comparisons to experimental data. The development of an STLE detection procedure in an a priori manner will also be discussed. [Preview Abstract] |
Tuesday, November 22, 2016 9:57AM - 10:10AM |
M31.00010: High speed velocimetry and concentration measurements in a microfluidic mixer using fluorescence confocal microscopy Venkatesh Inguva, Blair Perot, Sagar Kathuria, Jonathan Rothstein, Osman Bilsel This work experimentally examines the performance of a quasi-turbulent micro-mixer that was designed to produce rapid mixing for protein-folding experiments. The original design of the mixer was performed using Direct Numerical Simulation (DNS) of the flow field and LES of the high Sc number scalar field representing the protein. The experimental work is designed to validate the DNS results. Both the velocity field and the protein concentration require validation. Different experiments were carried out to measure these two quantities. Concentration measurements are performed using a 488nm continuous wave laser coupled with a confocal microscope to measure fluorescence intensity during mixing. This is calibrated using the case where no mixing occurs. The velocity measurements use a novel high speed velocimetry technique capable of measuring speeds on the order of 10 m/s in a micro channel. The technique involves creating a pulsed confocal volume from a Ti-Sapphire laser with a pulse width of 260ns and observing the decay of fluorescence due to the fluid motion. Results from both experiments will be presented along with a comparison to the DNS results. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2025 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700