MHz-rate nitric oxide planar laser-induced fluorescence imaging in a Mach 10 hypersonic wind tunnel
Naibo Jiang,Matt Webster,Walter R. Lempert,Joseph D. Miller,Terrence R. Meyer,Christopher B. Ivey,Paul M. Danehy +6 more
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Nitric oxide planar laser-induced fluorescence (NO PLIF) imaging at repetition rates as high as 1 MHz is demonstrated in the NASA Langley 31 in.Abstract:
Nitric oxide planar laser-induced fluorescence (NO PLIF) imaging at repetition rates as high as 1MHz is demonstrated in the NASA Langley 31 in. Mach 10 hypersonic wind tunnel. Approximately 200 time-correlated image sequences of between 10 and 20 individual frames were obtained over eight days of wind tunnel testing spanning two entries in March and September of 2009. The image sequences presented were obtained from the boundary layer of a 20° flat plate model, in which transition was induced using a variety of different shaped protuberances, including a cylinder and a triangle. The high-speed image sequences captured a variety of laminar and transitional flow phenomena, ranging from mostly laminar flow, typically at a lower Reynolds number and/or in the near wall region of the model, to highly transitional flow in which the temporal evolution and progression of characteristic streak instabilities and/or corkscrew-shaped vortices could be clearly identified.read more
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50-kHz-rate 2D imaging of temperature and H2O concentration at the exhaust plane of a J85 engine using hyperspectral tomography.
Lin Ma,Xuesong Li,Scott T. Sanders,Andrew W. Caswell,Sukesh Roy,David H. Plemmons,James R. Gord +6 more
TL;DR: A novel laser diagnostic technique, named hyperspectral tomography (HT), enables simultaneous 2-dimensional imaging of temperature and water-vapor concentration at 225 spatial grid points with a temporal response up to 50 kHz for high-speed reactive flows.
Journal ArticleDOI
High speed imaging in fundamental and applied combustion research
TL;DR: High-speed imaging of turbulent flames and internal combustion engines allowed capturing and identifying detrimental conditions that might be rare in occurrence and defining in leading to failure, such as small variations in boundary conditions, e.g. flow patterns or the formation of a fuel spray, might lead to combustion failures that can range from acoustic noise in a jet flame, a misfire in an automobile engine, to lean-blowout of an aircraft gas turbine engine; from nuisance to catastrophe.
Journal ArticleDOI
Review of ultra-high repetition rate laser diagnostics for fluid dynamic measurements
TL;DR: The pulse burst laser system as mentioned in this paper produces high repetition rate output by slicing the output of a low power continuous wave laser and passing the resulting burst of pulses through a series of pulsed Nd:YAG amplifiers.
Journal ArticleDOI
Premixed flames subjected to extreme turbulence: Some questions and recent answers
James F. Driscoll,Jacqueline H. Chen,Aaron W. Skiba,Aaron W. Skiba,Campbell D. Carter,Evatt R. Hawkes,Haiou Wang +6 more
TL;DR: A review of recent experimental and DNS results that have been obtained for the range of extreme turbulence, and it includes a discussion of cases that agree or disagree with predictions is provided in this article.
Proceedings ArticleDOI
Application of the Cross Wavelet Transform and Wavelet Coherence to OH-PLIF in Bluff-Body Stabilized Flames
TL;DR: In this paper, the authors employ the continuous wavelet transform (CWT) to characterize and quantify the nature of shedding in bluff body stabilized flames and evaluate the potential for utilizing advanced numerical tools for extracting information about coherent structure dynamics in complex reacting flows.
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Megahertz Pulse-Burst Laser and Visualization of Shock-Wave/Boundary-Layer Interaction
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High repetition rate planar laser induced fluorescence of OH in a turbulent non-premixed flame
TL;DR: In this article, a planar laser induced fluorescence (PLIF) imaging of the OH radical is presented in a turbulent non-premixed methane-air flame, which can be resolved sequentially at several kHz repetition rates.