Matching theory to characterize sound emission during vortex reconnection in quantum fluids

Proment, Davide; Krstulovic, Giorgio

doi:10.1103/physrevfluids.5.104701

Cited by 7 publications

(2 citation statements)

References 45 publications

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“…The behaviour of here is similar to that observed in experiments in classical fluids by Scheeler et al. (2014) and also simulations in superfluids by Proment & Krstulovic (2020). Before reconnection, continues to decrease.…”

Section: Topological Aspects Of Helicity Dynamicssupporting

confidence: 91%

Helicity dynamics in viscous vortex links

et al. 2022

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The dynamics of two slender Hopf-linked vortex rings at vortex Reynolds numbers ( $Re \equiv \varGamma /\nu, \mathrm {circulation/viscosity}$ ) $2000$ , $3000$ and $4000$ is studied using direct numerical simulations of the incompressible Navier–Stokes equations. Under self-induction, the initially perpendicularly placed vortex rings approach each other and reconnect to form two separate vortex rings. The leading ring is closely cuddled and further undergoes secondary reconnection to form two even smaller rings. At high $Re$ , the leading ring and the subsequent smaller rings are unstable and break up into turbulent clouds consisting of numerous even smaller-scale structures. Although the global helicity $H$ remains constant before reconnection, it increases and then rapidly decays during reconnection – both the growth and decay rates increase with $Re$ . In the two higher $Re$ (i.e. 3000 and 4000) cases, $H$ further rises after the first reconnection and reaches a quasi-plateau with the asymptotic value continuously increasing with $Re$ – suggesting that $H$ for viscous flows is not conserved at very high $Re$ . Further flow analysis demonstrates that significant numbers of positive and negative helical structures are simultaneously generated before and during reconnection, and their different decay rates is the main reason for the complex evolution of $H$ . By examining the topological aspects of the helicity dynamics, we find that, different from $H$ , the sum of link and writhe ( $L_k+W_r$ ) continuously drop during reconnection. Our results also clearly demonstrate that the twist, which increases with $Re$ , plays a significant role in the helicity dynamics, particularly at high $Re$ .

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Section: Topological Aspects Of Helicity Dynamicssupporting

confidence: 91%

Helicity dynamics in viscous vortex links

et al. 2022

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“…Here we have made the assumption that the energy flux in the Kolmogorov range is the same as in the Kelvin wave cascade. This strong assumption might be questioned as energy could be already dissipated into sound by vortex reconnections at different scales diminishing this value [22,53]. Such extra sinks of energy are difficult to quantify and we will not take them into account.…”

Section: A a Brief Overview Of Cascades In Quantum Turbulencementioning

confidence: 99%

Kolmogorov and Kelvin wave cascades in a generalized model for quantum turbulence

Müller

Krstulovic

2020

Phys. Rev. B

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We performed numerical simulations of decaying quantum turbulence by using a generalized Gross-Pitaevskii equation that includes a beyond mean field correction and a nonlocal interaction potential. The nonlocal potential is chosen in order to mimic He II by introducing a roton minimum in the excitation spectrum. We observe that at large scales the statistical behavior of the flow is independent of the interaction potential, but at scales smaller than the intervortex distance a Kelvin wave cascade is enhanced in the generalized model. In this range, the incompressible kinetic energy spectrum obeys the weak wave turbulence prediction for Kelvin wave cascade not only for the scaling with wave numbers but also for the energy flux and the intervortex distance.

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