Journal ArticleDOI
Quantification of aero-optical phase distortion using the small-aperture beam technique
Eric J. Jumper,Ronald J. Hugo +1 more
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TLDR
In this paper, a small-aperture beam technique was proposed for quantifying the instantaneous optical wave front distortions imposed by propagation through an optically active, turbulent flowfield.Abstract:
We discuss the small-aperture beam technique, a new way of experimentally quantifying the instantaneous optical wave front distortions imposed by propagation through an optically active, turbulent flowfield. We lay out the theoretical basis for the technique and the relationship of the measured jitter of a small-aperture probe beam to optical path difference. A numerical simulation of a two-dimensional heated jet is used to explore the validity of using beam-jitter signals from multiple probe beams to obtain optical path difference in a flow region where eddy production constitutes the major character of the turbulent flowfield.read more
Citations
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Journal ArticleDOI
Recent advances in aero-optics
TL;DR: A brief discussion of the traditional approach to quantifying aero-optic interactions is given in this paper, where the authors review how the development of high-speed wavefront sensors over the past 10 years has impacted the fluid-dynamics and optics fields.
Journal ArticleDOI
The optical distortion mechanism in a nearly incompressible free shear layer
TL;DR: In this paper, the authors examined the mechanisms which produce a variable-density field (and accompanying index-of-refraction field) in a nearly incompressible shear-layer flow.
Journal ArticleDOI
Flow structure and optical beam propagation in high-Reynolds-number gas-phase shear layers and jets
TL;DR: In this paper, the structure of the scalar index-of-refraction field generated by turbulent, gas-phase, incompressible and compressible shear layers and incompressibly jets, and on associated beam-propagation aero-optical phenomena was investigated.
Journal ArticleDOI
Aero-Optical and Flow Measurements Over a Flat-Windowed Turret
TL;DR: In this paper, an extensive investigation of the aberrating character of optical distortions over a hemisphere-on-cylinder turret with a window was performed using a two-dimensional wave frontsensor and a Malley probe.
Journal ArticleDOI
Physics and Measurement of Aero-Optical Effects: Past and Present
TL;DR: A review of the early and present periods of research in aero-optics can be found in this article, which traces the activities and developments associated with both periods but particularly focuses on the development of modern high-bandwidth wavefront sensors used in the present research period.
References
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Book
The Structure of Turbulent Shear Flow
TL;DR: In this paper, the authors present a method to find the optimal set of words for a given sentence in a sentence using the Bibliogr. Index Reference Record created on 2004-09-07, modified on 2016-08-08
Book
Principles of Adaptive Optics
TL;DR: This chapter discusses the development of Adaptive Optics Imaging Systems, which combines Nonlinear Optics with Linear Analysis of Random Wavefronts, and its applications in Wavefront Reconstruction and System Engineering.
Journal ArticleDOI
A Theory of Radio Scattering in the Troposphere
Henry G. Booker,W. E. Gordon +1 more
TL;DR: In this paper, the theory of scattering by a turbulent medium is applied to scattering of radio waves in the troposphere, where energy is received by diffraction round the curved surface of the earth (modified as appropriate by atmospheric refraction), and by scattering from turbulence in the region of high field strength above the horizon.
Journal ArticleDOI
Self-excited oscillations and mixing in a heated round jet
TL;DR: In this article, an axisymmetric hot-air jet discharging into cold ambient air is investigated experimentally and it is demonstrated by several different experiments that, for sufficiently low Reynolds number and a ratio of jet exit to ambient density below approximately 0.7, global oscillations of the "jet column" become self-excited, a behaviour which is related to local absolute instability in the potential core region.
Journal ArticleDOI
Effect of turbulent fluctuations in an optically active fluid medium.
TL;DR: In this paper, the effect of a beam traversing an optically active medium of turbulent fluctuations of the index of refraction in the medium is investigated theoretically, and the general far-field case is solved by integration of the wave equation with both gain and fluctuations of index refraction, simplified by neglecting the Laplacian of the fluctuating part of the electric field.