Hydrodynamics of random-organizing hyperuniform fluids

Lei, Qun-Li; Ni, Ran

doi:10.1073/pnas.1911596116

Cited by 71 publications

(54 citation statements)

References 63 publications

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“…In figure 2, we compare the simulation results to the predictions from the strong-contrast approximations [Eqs. (43) and (44) for local approximations, and Eqs. (51) and (52) for the nonlocal counterparts] as well as the Gaunaurd-Überall approximation (GUA) [(B.1) and (B.2)].…”

Section: Comparison Of Simulations To Various Approximationsmentioning

confidence: 99%

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Effective elastic wave characteristics of composite media

Kim

Torquato

2020

New J. Phys.

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We derive exact expressions for effective elastodynamic properties of two-phase composites in the long-wavelength (quasistatic) regime via homogenized constitutive relations that are local in space. This is accomplished by extending the "strong-contrast" expansion formalism that was previously applied to the static problem. These strong-contrast expansions explicitly incorporate complete microstructural information of the composite via an infinite set of n-point correlation functions. Utilizing the rapid-convergence properties of these series expansions (even for extreme contrast ratios), we extract accurate approximations that depend on the microstructure via the spectral density, which is easy to compute or measure for any composite. We also investigate the predictive power of modifications of such approximation formulas postulated elsewhere [J. Kim and S. Torquato, Proc. Nat. Acad. Sci. 117, 8764 (2020)] to extend their applicability beyond the quasistatic regime. The accuracy of these nonlocal microstructure-dependent approximations is validated by comparison to full-waveform simulation results for certain models of dispersions. We apply our formulas to a variety of models of nonhyperuniform and hyperuniform disordered composites. We demonstrate that hyperuniform systems are less lossy than their nonhyperuniform counterparts in the quasistatic regime, and stealthy hyperuniform media can be perfectly transparent for a wide range of wavenumbers. Finally, we discuss how to utilize our approximations for engineering composites with prescribed elastic wave characteristics.

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Section: Comparison Of Simulations To Various Approximationsmentioning

confidence: 99%

“…Comparison of the predictions of the local strong-contrast approximations [Eqs (43). and(44)], the nonlocal variants [Eqs (51). and(52)] and GUA [Eqs.…”

mentioning

confidence: 99%

Effective elastic wave characteristics of composite media

Kim

Torquato

2020

New J. Phys.

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“…Hyperuniform disorded (HUD) media are statistically isotropic and possess a constrained randomness such that density fluctuations on large scales behave more like those of ordered solids, rather than those of conventional amorphous materials. [27][28][29][30] HUD patterns naturally arise in many physical systems, from the mass distribution in the early universe, 31 structure of prime numbers, 32 hydrodynamics, 33 structure of amorphous ices, 34 sheared sedimenting suspensions, 35 to wave localisation 36 or colloidal packing. 37 When translated into photonic materials, HUDs exhibit large and robust photonic band gaps as in photonic crystals, but are both complete and isotropic.…”

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confidence: 99%

Over 65% sunlight absorption in a 1 μm Si slab with hyperuniform texture

Tavakoli¹,

Spalding²,

Koppejan³

et al. 2020

Preprint

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Thin, flexible and invisible solar cells will be an ubiquitous technology in the near future. Ultrathin crystalline silicon (c-Si) cells capitalise on the success of bulk silicon cells while being light-weight and mechanically flexible, but suffer from poor absorption and efficiency. Here we present a new family of surface texturing, based on correlated disordered hyperuniform patterns, capable of efficiently coupling the incident spectrum into the silicon slab optical modes. We experimentally demonstrate 66.5% solar light absorption in free-standing 1 µm c-Si layers by hyperuniform nanostructuring. The absorption equivalent photocurrent derived from our measurements is 26.3 mA/cm2, which is far above the highest found in literature for Si of similar thickness. Considering state-of-the-art Si PV technologies, the enhanced light trapping translates to a record efficiency above 15%. The light absorption can potentially be increased up to 33.8 mA/cm2 by incorporating a back-reflector and improved anti-reflection, for which we estimate a photovoltaic efficiency above 21% for 1 µm thick Si cells.

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“…Generally, this exponential value of the scaling law is used to describe the spatial-ordered features. It is called "hyperuniformity" when the exponent of the density fluctuation is less than −2.0, where the long-wavelength density fluctuations are suppressed [39]. In sum, the exponent of density fluctuation is also useful to quantify the spatial patterns between AC model and CH/CHPD models.…”

Section: Density Fluctuationmentioning

confidence: 99%

Quantitatively Inferring Three Mechanisms from the Spatiotemporal Patterns

Zhang

Liu

2020

Mathematics

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Although the diversity of spatial patterns has gained extensive attention on ecosystems, it is still a challenge to discern the underlying ecological processes and mechanisms. Dynamical system models, such partial differential equations (PDEs), are some of the most widely used frameworks to unravel the spatial pattern formation, and to explore the potential ecological processes and mechanisms. Here, comparing the similarity of patterned dynamics among Allen–Cahn (AC) model, Cahn–Hilliard (CH) model, and Cahn–Hilliard with population demographics (CHPD) model, we show that integrated spatiotemporal behaviors of the structure factors, the density-fluctuation scaling, the Lifshitz–Slyozov (LS) scaling, and the saturation status are useful indicators to infer the underlying ecological processes, even though they display the indistinguishable spatial patterns. First, there is a remarkable peak of structure factors of the CH model and CHPD model, but absent in AC model. Second, both CH and CHPD models reveal a hyperuniform behavior with scaling of −2.90 and −2.60, respectively, but AC model displays a random distribution with scaling of −1.91. Third, both AC and CH display uniform LS behaviors with slightly different scaling of 0.37 and 0.32, respectively, but CHPD model has scaling of 0.19 at short-time scales and saturation at long-time scales. In sum, we provide insights into the dynamical indicators/behaviors of spatial patterns, obtained from pure spatial data and spatiotemporal related data, and a potential application to infer ecological processes.

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Hydrodynamics of random-organizing hyperuniform fluids

Cited by 71 publications

References 63 publications

Effective elastic wave characteristics of composite media

Effective elastic wave characteristics of composite media

Over 65% sunlight absorption in a 1 μm Si slab with hyperuniform texture

Quantitatively Inferring Three Mechanisms from the Spatiotemporal Patterns

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