Digital Strain and Temperature Imaging Technique

Marino, Robert; Westring, Brice; Laufer, Gabriel; Krauss, Roland H.; Whitehurst, R.

doi:10.2514/2.819

Cited by 15 publications

(8 citation statements)

References 10 publications

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“…Negligible unsteadiness was recorded by Finley in the single-cell jet pattern (the SPM jet structure) at high pressure ratios and the single-cell pattern was considered globally stable. McGhee [128], Karpman [147], and Nishida et al [139] F findings whereas an associated lateral asymmetric motion of the jet was also reported [144,148,155]. Debiève et al [148] pointed out that instability could become less intense is the opposing jet was at an angle with respect to the freestream.…”

Section: Studies On Flow Unsteadiness Associated With Counterflow Jetsmentioning

confidence: 99%

“…In addition, the location of reattachment is pushed outwards which weakens the reattachment shock and causes the reattachment pressure and heat flux peaks to drop. Meyers et al [144] showed that both skin friction drag and aeroheating reduction were correlated to larger jet size. Eventually, the overall drag and aeroheating on the vehicle are reduced [145,146].…”

Section: Principle Of Operation Of Counterflow Jetsmentioning

confidence: 99%

“…The first measure was the thrust coefficient of the jet defined as the jet thrust divided by the product of freestream dynamic pressure and reference area. It was introduced by Love [125] and later used by McGhee [128] and Meyers et al [144]. Pamadi [135] used exactly the same measure under a different name; the momentum coefficient.…”

Section: Measures Of Opposing Jet Strengthmentioning

confidence: 99%

“…More importantly, high pressure jets yield high retarding thrust (i.e., more drag). If sufficiently high, the drag reduction benefits can be overwhelmed by the retarding thrust and the opposing jet would act as a drag generator rather than reducer [128,135,144,155,160,164,193]. This was contradicted by the findings of Shang et al [136].…”

Section: Design Tradeoffs and Issues Of Practical Implementation Of Omentioning

confidence: 99%

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Forebody shock control devices for drag and aero-heating reduction: A comprehensive survey with a practical perspective

Ahmed

Qin

2020

Progress in Aerospace Sciences

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One key feature that distinguishes the flowfield around vehicles flying in supersonic and hypersonic regimes is the bow shock wave ahead of forebody. The severe drag and aeroheating impacting these vehicles can be significantly reduced if the bow shock wave ahead of the vehicles forebodies is controlled to yield weaker system of oblique shocks. Benefits of forebody shock control include increasing flight ranges, economizing fuel consumption, reducing dead weights, and thermally protecting forebody structure and onboard equipment. Forebody shock control that has been widely studied since the early 1900s is achievable in numerous techniques that vary according to the mechanism of control. While some of these techniques have already been implemented in real systems, other techniques involve serious complications and tough trade-offs. The present paper is intended to serve as the first comprehensive survey on the field of forebody shock control devices. The objectives of the present paper are multifold. The paper categorizes the various forebody shock control devices in a physics-based manner, explains the underlying physics for each device, and surveys the key studies and state-of-the-art knowledge. The paper also addresses the existing gaps in knowledge, highlights the existing systems implementing these devices, and discusses the associated practical implementation issues and design-tradeoffs. 2. Structural devices, the mechanical spikes: 2.1. Principle of operation of mechanical spikes Drag and Aeroheating Reduction Devices Fluidic Devices Opposing jets Structural Devices Mechanical spikes Energetic Devices Energy deposition Basic devices Structural-Fluidic Devices Structural-Energetic Devices Hybrid devices

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Section: Studies On Flow Unsteadiness Associated With Counterflow Jetsmentioning

confidence: 99%

Section: Principle Of Operation Of Counterflow Jetsmentioning

confidence: 99%

Section: Measures Of Opposing Jet Strengthmentioning

confidence: 99%

Section: Design Tradeoffs and Issues Of Practical Implementation Of Omentioning

confidence: 99%

See 2 more Smart Citations

Forebody shock control devices for drag and aero-heating reduction: A comprehensive survey with a practical perspective

Ahmed

Qin

2020

Progress in Aerospace Sciences

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“…The spectrally resolved technique [17,18] is based on monitoring the emission versus wavelength. A typical spectrum of Mg 4 FGeO 6 : Mn with a dispersion of 0.7 nm is shown in Fig.…”

Section: Fig 2 Phosphorescence Decays Measured At Different Temperatmentioning

confidence: 99%

Surface Temperature Measurement Of Flame Spread Using Thermographic Phosphors

Ohtani¹

2003

Fire Safety Science - Proceedings of the Seventh International

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A technique based on remote measurements of surface temperature in connection to fires is presented. Pulsed ultraviolet laser radiation at 266 nm and 7 ns duration was used to excite a thermographic phosphor, Mg 4 FGeO 6 : Mn, which was adapted on the surface of the investigated material. The laser-induced emission from the phosphor was recorded. A calibration of the phosphorescence lifetime and spectral properties against temperature allowed surface temperature measurements between 25°C and 500°C. The method was tested and compared with thermocouple measurements on burning materials such as lowdensity fiberboards and polymethylmetacrylate.

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Laser‐Induced Fluorescence Imaging

Allison

Partridge

2002

Encyclopedia of Imaging Science and Technology

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Fluorescence imaging is a tool of increasing importance in aerodynamics, fluid‐flow visualization, and nondestructive evaluation in a variety of industrial circumstances. It is a means for producing two‐dimensional images of real surfaces or fluid cross‐sectional areas that correspond to properties such as temperature or pressure. This article discusses three major laser‐induced fluorescence imaging techniques: Planar laser induced fluorescence; phosphor thermography are pressure‐sensitive paint. Since the 1980s, planar laser induced fluorescence (PLIF) has been used for combustion diagnostics and to characterize gas and liquid phase fluid‐flow situations. Depending on the application, the technique can determine species concentration, partial pressure, temperature, flow velocity, or flow distribution‐visualization. Phosphor thermography (PT) is used to image surface temperature distributions. Fluorescence imaging of aerodynamic surfaces coated with phosphor material for thermometry purposes dates back to the 1940s and development of the technique continues today. Imaging of fluorescence from pressure‐sensitive paint (PSP) is a third diagnostic approach to aerodynamic and propulsion research discussed here and it has received much attention during the past decade. These three methodologies appear to be the primary laser‐induced fluorescence imaging applications outside medicine and biology. PLIF is more developed than the PT or PSP applications.

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Digital Strain and Temperature Imaging Technique

Cited by 15 publications

References 10 publications

Forebody shock control devices for drag and aero-heating reduction: A comprehensive survey with a practical perspective

Forebody shock control devices for drag and aero-heating reduction: A comprehensive survey with a practical perspective

Surface Temperature Measurement Of Flame Spread Using Thermographic Phosphors

Laser‐Induced Fluorescence Imaging

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