Unveiling the spectrum of electrohydrodynamic turbulence in dust storms

Zhang, Huan; Zhou, Youhe

doi:10.1038/s41467-023-36041-x

Cited by 16 publications

(12 citation statements)

References 55 publications

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“…Upon meticulous examination of our data, we observe that our electrohydrodynamic power spectrum exhibits a scaling behaviour consistent with the Kolmogorov power law within the intermediate scales of frequency. This observation is consistent with the recent field measurements of dust storms on Earth as cited in Zhang and Zhou (2023), and it underscores the relevance and significance of our findings. This similarity between the electric field dynamics in our dust storms and other studied systems underscores the potential universality of this scaling behaviour.…”

Section: Resultssupporting

confidence: 93%

Turbulence-induced electrical discharges in charged particle-laden Martian boundary layers

Rahman,

Saieed,

Hickey

2023

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Martian dust storms in the planetary boundary layer share many qualitative similarities to terrestrial sandstorms. Both of these turbulence-driven, particle-laden boundary layer flows are known to generate electric fields due to the transport of differentially charged particles; this charge separation can be strong enough to lead to dielectric breakdown in the form of sparks or lightning. Using wall-modelled large-eddy simulations supplemented with conservation of equations for the charged particle transport, representative simulations of neutrally stable Martian and terrestrial particle-laden boundary layer flows are compared. The simulations, albeit canonical in nature, provide evidence to support previous observations of the less frequent occurrence of lightning on Mars but a higher occurrence of localised electric discharge events due to the much lower breakdown potential. The rarefied Martian atmosphere impedes charged particle transport, resulting in a weaker electric field than the equivalent terrestrial sandstorm. The lower drag force in the rarefied Martian atmosphere means that the electrostatic force plays a more significant role in the particle transport, which results in a self-regulation of the electric field. The strongest Martian dust storms show evidence of significant breakdown events and these discharge events only occur very close to the ground despite the very large boundary layer on Mars.

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Section: Resultssupporting

confidence: 93%

Turbulence-induced electrical discharges in charged particle-laden Martian boundary layers

Rahman,

Saieed,

Hickey

2023

Flow

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“…Since the upper bounds of the inertial ranges for the PM10 dust concentration and three components of electric field are nearly equal, only τ IR ez are shown herein. It is noteworthy that the upper bounds τ IR e are found to be approximately one order of magnitude larger than τ IR f , as previously reported by Zhang & Zhou (2023).…”

Section: Descriptions Of the Datasetssupporting

confidence: 85%

“…The upper bounds of the inertial ranges of the streamwise wind velocity and wall-normal electric field are determined using a method based on a best fit of their power spectral densities, below which the spectral indexes are within of (see Kasper et al. 2021; Zhang & Zhou 2023). The main parameters of the selected datasets are given in table 1.…”

Section: Methodsmentioning

confidence: 99%

“…The estimations of Kolmogorov time scales τ η = (ν/ε) 1/2 are implemented by determining the turbulent kinetic energy dissipation rate ε from the Kolmogorov 4/5 law in the inertial range (Kolmogorov 1941;Pope 2000;Xie & Bühler 2019). The upper bounds of the inertial ranges of the streamwise wind velocity τ IR f and wall-normal electric field τ IR ez are determined using a method based on a best fit of their power spectral densities, below which the spectral indexes are within ±10 % of −5/3 (see Kasper et al 2021;Zhang & Zhou 2023). The main parameters of the selected datasets are given in table 1.…”

Section: Descriptions Of the Datasetsmentioning

confidence: 99%

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Multifield intermittency of dust storm turbulence in the atmospheric surface layer

2023

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Dust storms are typical dispersed two-phase atmospheric turbulence involving electrified charged dust particles. Previous observations have demonstrated that clean-air atmospheric turbulence is strongly intermittent. However, the intermittency of the wind velocity, concentration of dust particles with a diameter smaller than $10\ \mathrm {\mu }{\rm m}$ (PM10) and electric fields, known as multifield intermittency, has not been reported or characterized yet. Here, we quantify the small-scale multifield intermittency of dust storms using datasets obtained from the Qingtu Lake Observation Array and a wavelet-based data analysis technique. The results indicate that the probability density functions of the multifield increments are scale dependent, and the scaling exponents of the multifield structure functions exhibit anomalous scaling, suggesting that the multiple fields in dust storms are also highly intermittent. Specifically, the wind velocity during dust storms appears to be more intermittent as compared with clean-air conditions. Among the multiple fields, the small-scale intermittency is strongest for PM10 dust concentration, moderate for electric fields and weakest for wind velocity. Furthermore, the anomalous scaling of multiple fields is well described by the hierarchical structure theory of turbulence. It is theoretically predicted that the wind velocity displays a one-dimensional filamentary structure, while the PM10 dust concentration and electric fields display two-dimensional sheet-like structures. Finally, after removing the coherent components of the observed time series by the proposed wavelet conditioning statistics, Kolmogorov linear scaling is recovered for the multiple fields, suggesting that small-scale multifield intermittency is caused by the presence of small-scale coherent structures.

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“…2018) and pneumatic powder transports (Nifuku & Katoh 2003; Grosshans & Papalexandris 2016) in industrial processes, and sand saltation (Schmidt, Schmidt & Dent 1998; Zheng, Huang & Zhou 2003), dust storms (Yair et al. 2016; Zhang & Zheng 2018; Zhang & Zhou 2020, 2023) and volcanic eruptions (Mather & Harrison 2006; Méndez Harper & Dufek 2016) in atmospheric flows. Field and laboratory measurements regarding these phenomena have shown that the mean electric field produced by charged particles can reach strengths of several hundred kilovolts per metre, so that the inter-particle electrostatic force is comparable with the particle's gravitational force and thus affects the particle behaviour considerably (Renno & Kok 2008).…”

Section: Introductionmentioning

confidence: 99%

How electrostatic forces affect particle behaviour in turbulent channel flows

2023

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In dispersed two-phase flows, particle electrification is a prevalent phenomenon that plays a crucial role in particle transport. However, the influences of electrostatic forces on particle behaviour in wall-bounded turbulent flows, especially in bidisperse cases, is not well understood. In this study, using direct numerical simulations based on a coupled Eulerian–Lagrangian point-particle approach at friction Reynolds number $Re_\tau =550$ , we demonstrate that when the electrostatic Stokes number is of the order of $O(10^{-1})$ , electrostatic forces could considerably alter particle behaviour in both monodisperse and bidisperse particle-laden turbulent channel flows. Specifically, the wall-normal profiles of the particle concentration are determined by the competition of turbophoresis, biased sampling and electrostatic effects. The electrostatic forces are found to reduce the concentrations of lighter particles by electrostatic drift directly, whereas they alter those of heavier particles by strengthening turbophoresis indirectly. With increasing electrical charge, the dynamics of the lighter particles remains approximately unchanged, but that of the heavier particles is modulated significantly due to their relatively strong particle–electrostatic interaction. In the near-wall region, electrostatic forces tend to homogenize the distribution of lighter particles in the spanwise direction by inhibiting the formation and destruction of particle clusterings and voids, thereby maintaining the anisotropic streaky clusterings. Furthermore, even though the clustering dynamics remains unchanged, the spatial extents of the clusterings at the channel centreline are suppressed (enhanced) by a factor of two, probably due to the remarkable reduction (increase) of particle concentration in this layer.

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Unveiling the spectrum of electrohydrodynamic turbulence in dust storms

Cited by 16 publications

References 55 publications

Turbulence-induced electrical discharges in charged particle-laden Martian boundary layers

Turbulence-induced electrical discharges in charged particle-laden Martian boundary layers

Multifield intermittency of dust storm turbulence in the atmospheric surface layer

How electrostatic forces affect particle behaviour in turbulent channel flows

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