Fluctuation Measurements in the Turbulent Boundary Layer of a Supersonic Flow

Schreyer, Anne-Marie; Gaisbauer, U.; Krämer, Ewald

doi:10.1007/978-90-481-3723-7_102

Cited by 2 publications

(2 citation statements)

References 6 publications

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“…At the same time according to the relationship between the electron density fluctuations and the temperature fluctuations, the relationship of the conservative passive amount with the electron density fluctuations can be determined, and then the variance of the electron density relationship can be deduced [29], [30]. Owing to the lack of sufficient practical data on a specific reentry vehicle even in RAM project, the estimated normalized variance can be obtained only from the partial data from rocket plume.…”

Section: A Model For the Time-varying Electron Density Of A Dynamic mentioning

confidence: 99%

Adaptive Multistate Markov Channel Modeling Method for Reentry Dynamic Plasma Sheaths

Shi

Liu

Fang

et al. 2016

IEEE Trans. Plasma Sci.

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Channel modeling of a plasma sheath for hypersonic reentry vehicles is important in addressing reentry communication blackout issues. Given that the time-varying property of the transmission medium is caused by physical factors such as largescale flight conditions variation, especially angle of attack, and small-scale fluid turbulence, a new adaptive multistate Markov channel modeling method is proposed to present the dynamic effects of reentry plasma sheaths on wireless channels. First, a quasi-Gaussian function mathematical model for the electron density of a dynamic plasma sheath is established according to the variation frequency of the dynamic physical factors. Then, the time-varying attenuation is calculated by combining the quasi-static Monte Carlo and uniform hierarchical analytical methods for nonuniform electronic density distribution. Finally, a hidden Markov model is employed to model the channel characteristics of the dynamic plasma sheath, and a reversiblejump Markov chain Monte Carlo algorithm is used to adaptively estimate the channel parameters of the multistate Markov channel. Simulation results show that the first-order statistical properties of the proposed channel are in good agreement with the calculated variable attenuation of radio waves, and this method has the adaptive capacity to estimate the number of multiple states and the channel parameters in each state without a need for manual setting. IndexTerms-Dynamic plasma sheath, Markov channel, reversible-jump Markov chain Monte Carlo algorithm (RJ-MCMC).

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Section: A Model For the Time-varying Electron Density Of A Dynamic mentioning

confidence: 99%

Adaptive Multistate Markov Channel Modeling Method for Reentry Dynamic Plasma Sheaths

Shi

Liu

Fang

et al. 2016

IEEE Trans. Plasma Sci.

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show abstract

“…Relevant literatures imply that the time-varying rate can be as high as 100-200 kHz. [4][5][6][7] However, the degree of time variation and the specific time-varying law of the plasma parameters in the actual flight phase are not clear. The time-varying calculation of the plasma sheath involves the calculation of turbulence and time-consuming hydrodynamical simulations, which is a very complex and challenging subject, and there is no reliable calculation of the results as so far.…”

Section: Introductionmentioning

confidence: 99%

An integrative time-varying frequency detection and channel sounding method for dynamic plasma sheath

et al. 2018

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The plasma sheath-surrounded hypersonic vehicle is a dynamic and time-varying medium and it is almost impossible to calculate time-varying physical parameters directly. The in-fight detection of the time-varying degree is important to understand the dynamic nature of the physical parameters and their effect on re-entry communication. In this paper, a constant envelope zero autocorrelation (CAZAC) sequence based on time-varying frequency detection and channel sounding method is proposed to detect the plasma sheath electronic density time-varying property and wireless channel characteristic. The proposed method utilizes the CAZAC sequence, which has excellent autocorrelation and spread gain characteristics, to realize dynamic time-varying detection/channel sounding under low signal-to-noise ratio in the plasma sheath environment. Theoretical simulation under a typical time-varying radio channel shows that the proposed method is capable of detecting time-variation frequency up to 200 kHz and can trace the channel amplitude and phase in the time domain well under –10 dB. Experimental results conducted in the RF modulation discharge plasma device verified the time variation detection ability in practical dynamic plasma sheath. Meanwhile, nonlinear phenomenon of dynamic plasma sheath on communication signal is observed thorough channel sounding result.

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Fluctuation Measurements in the Turbulent Boundary Layer of a Supersonic Flow

Cited by 2 publications

References 6 publications

Adaptive Multistate Markov Channel Modeling Method for Reentry Dynamic Plasma Sheaths

Adaptive Multistate Markov Channel Modeling Method for Reentry Dynamic Plasma Sheaths

An integrative time-varying frequency detection and channel sounding method for dynamic plasma sheath

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