Perspective: The Experimentalist and the Problem of Turbulence in the Age of Supercomputers

Gharib, Morteza

doi:10.1115/1.2817368

Cited by 11 publications

(7 citation statements)

References 45 publications

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“…However, experience showed that in order to study new phenomena experiments are still the most economical approach. The CFD codes, once validated against experimental data, are the most effective tool for the production of data to build a comprehensive flow database (Gharib, 1996).…”

Section: Integrated Approach With Quantitative Flow Field Visualizatimentioning

confidence: 99%

Integrated approach to computational and experimental flow visualization of a double annular confined jet

Hazarika

Vucinic

2001

J Vis

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The cold flow of a prototype industrial burner in a cylindrical combustion chamber is investigated. Two concentric annular axial jets simulate this complex flow field, which is investigated using Laser Sheet flow Visualization (LSV), Digital Particle Image Velocimetry (DPIV), Laser Doppler Velocimetry (LDV) and Computational Fluid Dynamics (CFD). The aim is to advance the physical understanding of combustion chamber flow fields and to assist the development of CFD codes specialized in such flows. These simulations generate large amount of data for various measured and calculated quantities. Thus, visualization and comparison procedures are applied for the validation of obtained results. The study reported here is one of the experiments applied in the design of the Quantitative Flow Field Visualization (QFView) software, a web-based environment which supports distributed data access. The application of QFView data analysis greatly improved the understandings about the various transition regions of the flow under investigation.

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Section: Integrated Approach With Quantitative Flow Field Visualizatimentioning

confidence: 99%

Integrated approach to computational and experimental flow visualization of a double annular confined jet

Hazarika

Vucinic

2001

J Vis

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“…Yeh and Cummins 6 and Cummins et al 5 originated the idea of using the Doppler shift in the frequency of the light scattered by particles or molecules in the ow to measure the ow velocity. The Doppler shift equation is given by (1) where s is the unit vector toward the observer/detector, o is the unit vector in the propagation direction of the laser light, V is the velocity vector of the light-scattering uid element/particle, and k is the wavelength of the laser light (refer to Fig. 1).…”

Section: Doppler Shiftmentioning

confidence: 99%

Review of Planar Multiple-Component Velocimetry in High-Speed Flows

Samimy

Wernet

2000

AIAA Journal

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High-speed ows encountered in most applications typically have very high Reynolds numbers and are often highly turbulent. Even in a laboratory-scale high subsonic or supersonic (high-speed) ow, velocities could vary over 3 orders of magnitude, and the turbulence spatial and temporal scales could span over 4-5 orders of magnitude. Exploring detailed physics of such ows presents major challenges to both experimental and computational researchers. An ultimate velocimetry technique would provide detailed, accurate, volumetric, real-time velocity data in such ows. With that being the goal, currently there are two planar velocimetry techniques that are developing rapidly into very useful tools with the potential of providing accurate velocity information in high-speed ows. The techniques are planar Doppler velocimetry (PDV) and particle imaging velocimetry (PIV). Whereas PDV has been under development for a relatively short period of time and is becoming a powerful technique, more accurate in high-speed ows, PIV is an established technique in low-speed ows and is now breaking ground in high-speed ows. The purpose of this review is to provide detailed background on these two techniques, to discuss the strengths and constraints of each technique, and to outline the areas in need of further improvement and development. The aims are to assist the novice users in their proper usage and to help those who are in the process of deciding which technique is more appropriate in their speci c applications. Mohammad(Mo) Samimyis a Professor and Associate Chair of Mechanical Engineering at the Ohio State University. He received his Ph.D. in 1984 in mechanical engineering from the University of Illinois at Urbana. His current research interests are gas dynamics, compressible turbulence, optical diagnostics, ow control, and aeroacoustics. Dr. Samimyhas been a visiting research fellow at NASA John H. Glenn Research Center at Lewis Field, Wright Laboratories, NASA Ames/Stanford Center for Turbulence Research, and CEAT/LEA Laboratories at the University of Poitiers in France, and has lectured extensively in the United States and abroad. He was an Associate Editor of the Journal of Propulsion and Power, is currently an Associate Editor of the AIAA Journal, and the chair elect of the AIAA Aerodynamic Measurement Technology Technical Committee. Dr. Samimy is a fellow of the American Society of Mechanical Engineers, an Associate Fellow of AIAA, and author or coauthor of over 100 technical papers. Mark Wernet received his Ph.D. in 1989 in chemical engineering from Case Western Reserve University in Cleveland, Ohio. He has been at NASA John H. Glenn Research Center at Lewis Field since 1985 in the Optical Instrumentation Technology Branch. His primary areas of interest are in the application of laser anemometry (both laser Doppler velocimetry and time of ight) and digital particle image velocimetry in turbomachinery and in microgravity. Dr. Wernet is currently a member of the AIAA Aerodynamic Measurement Technology Technical Committee.

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“…Numerical or computational fluid dynamic (CFD) modelling schemes of full scale aircraft have advanced substantially since the 1970's but assumptions must still be made. For example, if a complete solution of the Navier Stokes equations was to be obtained, a direct numerical simulation (DNS) would be required where the mesh density scales with Reynolds number Re 9/4 [4]. Therefore, given large civilian aircraft have Reynolds numbers based on wing chord in excess of 10 million, three dimensional mesh sizes in excess of 1 x 10 15 cells would be needed for a DNS model.…”

Section: Introductionmentioning

confidence: 99%

Jetstream 31 national flying laboratory: Lift and drag measurement and modelling

Lawson

Jacques

Gautrey

et al. 2017

Aerospace Science and Technology

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Lift and drag flight test data is presented from the National Flying Laboratory Centre, Jetstream 31 aircraft. The aircraft has been modified as a flying classroom for completing flight test training courses, for engineering degree accreditation. The straight and level flight test data is compared to data from 10% and 17% scale wind tunnel models, a Reynolds Averaged Navier Stokes steady-state computational fluid dynamics model and an empirical model. Estimated standard errors in the flight test data are ±2.4% in lift coefficient, ±2.7% in drag coefficient. The flight test data also shows the aircraft to have a maximum lift to drag ratio of 10.5 at Mach 0.32, a zero lift drag coefficient of 0.0376 and an induced drag correction factor of 0.0607. When comparing the characteristics from the other models, the best overall comparison with the flight test data, in terms of lift coefficient, was with the empirical model. For the drag comparisons, all the models under predicted levels of drag by up to 43% when compared to the flight test data, with the best overall match between the flight test data and the 10% scale wind tunnel model. These discrepancies were attributed to various factors including zero lift drag Reynolds number effects, omission of a propeller system and surface excrescences on the models, as well as surface finish differences.

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Perspective: The Experimentalist and the Problem of Turbulence in the Age of Supercomputers

Abstract: Due to the rising capabilities of computational fluid mechanics ( CFD)

Cited by 11 publications

References 45 publications

Integrated approach to computational and experimental flow visualization of a double annular confined jet

Integrated approach to computational and experimental flow visualization of a double annular confined jet

Review of Planar Multiple-Component Velocimetry in High-Speed Flows

Jetstream 31 national flying laboratory: Lift and drag measurement and modelling

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