Evolution of superfluid turbulence in thermal counterflow

Martin, K. P.; Tough, J. T.

doi:10.1103/physrevb.27.2788

Cited by 71 publications

(74 citation statements)

References 30 publications

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“…6(b). Our data again follow the calculated normal-fluid velocity, except below a transition heat flux at about 50 mW=cm 2 , which may correspond to the onset of quantum turbulence [19,20,24]. It is likely that, in the small heat flux regime, both the superfluid and the normal fluid are in a laminar flow state.…”

Section: Prl 105 045301 (2010) P H Y S I C a L R E V I E W L E T T Esupporting

confidence: 51%

“…At low heat fluxes, however, many molecules decayed radiatively before they could reach the observation region. The flow of the normal fluid was studied at heat fluxes that ranged from 160 to 1000 mW=cm 2 , above the onset heat flux for quantum turbulence (about 20 mW=cm 2 ) observed in channels with similar geometry [19,20]. An intensified CCD camera was used to record the fluorescent light from the line of excited molecules.…”

Section: Selected For a Viewpoint In Physics P H Y S I C A L R E V I mentioning

confidence: 99%

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Laminar, turbulent, or doubly turbulent?

Barenghi¹

2010

Physics

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Heat is transferred in superfluid 4 He via a process known as thermal counterflow. It has been known for many years that above a critical heat current the superfluid component in this counterflow becomes turbulent. It has been suspected that the normal-fluid component may become turbulent as well, but experimental verification is difficult without a technique for visualizing the flow. Here we report a series of visualization studies on the normal-fluid component in a thermal counterflow performed by imaging the motion of seeded metastable helium molecules using a laser-induced-fluorescence technique. We present evidence that the flow of the normal fluid is indeed turbulent at relatively large velocities. Thermal counterflow in which both components are turbulent presents us with a theoretically challenging type of turbulent behavior that is new to physics. DOI: 10.1103/PhysRevLett.105.045301 PACS numbers: 67.25.dk, 29.40.Gx, 47.27.Ài The superfluid phase of liquid 4 He exhibits two-fluid behavior [1]: a normal fluid, carrying all the thermal energy, coexists with a superfluid component. The proportion of superfluid falls from unity to zero as the temperature T rises from zero to the transition [1]. In a thermal counterflow, the normal-fluid velocity v n is related to the heat flux q by q ¼ STv n ;( 1) where is the total density and S is the entropy per unit mass [1]. Above a certain critical heat flux, superflow is known to become turbulent. This quantum turbulence takes the form of a disorganized tangle of quantized vortex lines [2,3]. A mutual friction force between the two fluids arises through the interaction between the quantized vortices and the normal fluid [4]. This type of quantum turbulence is maintained by the relative motion of the two fluids, through processes that are reasonably well understood [2,3]. Features in the observed relation between vortex density and heat flux suggest that the normal fluid may also become turbulent, and mutual friction has been shown theoretically to induce an instability in the laminar flow of the normal fluid [5]. Satisfactory evidence for such normalfluid turbulence can come only from a visualization of the normal-fluid flow. Techniques for such visualization have recently started to be developed. Turbulence in both fluids has been observed in other types of flow in liquid helium [6], such as that behind a moving grid [7]. But in those cases the two fluids are not forced to have any relative motion and behave like a single classical fluid, exhibiting a Kolmogorov energy spectrum [1]. Simultaneous turbulence in both fluids in a counterflow must be different, and it would be a type of turbulence that is new to physics. Past experiments on the visualization of thermal counterflow have used micron-sized tracer particles formed from polymer spheres or solid hydrogen, and they have been based on either particle image velocimetry [8] or particle tracking techniques [9]. The particle image velocimetry data obtained at large heat fluxes are hard to interpret since micron-s...

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Section: Prl 105 045301 (2010) P H Y S I C a L R E V I E W L E T T Esupporting

confidence: 51%

Section: Selected For a Viewpoint In Physics P H Y S I C A L R E V I mentioning

confidence: 99%

Laminar, turbulent, or doubly turbulent?

Barenghi¹

2010

Physics

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“…Unfortunately, there are not enough papers dealing with parallelepiped counterflow channels. In [17] Ladner and Tough consider four long channels with a rectangular 10b × b cross section with b = 0.0098 cm, b = 0.0047 cm, b = 0.0032 cm and b = 0.0091 cm in the range of temperatures 1.2 K to 1.8 K. According to their results, they found only one state of quantum turbulence (the TIII turbulent regime), which reveals that rectangular channel is simpler than quantum turbulence in cylindrical channel, where two kinds of turbulence have been detected [32,34].…”

Section: Discussionmentioning

confidence: 94%

“…The second solution is stable for q > q c1 = ρsST ρ βκω α 0 d , and in Ref. [34] it is seen that it has two different regimes, namely a TI turbulence and TII turbulence flow. In a channel with a rectangular cross section with high aspect ratio, instead, just one status was revealed, which suggests that the turbulence in these kind of channels is simpler than the one in the cylindrical channels.…”

Section: Turbulent Regime (Gorter-mellinck)mentioning

confidence: 99%

Effective thermal conductivity of superfluid helium: laminar, turbulent and ballistic regimes

Sciacca

Galantucci

2016

Communications in Applied and Industrial Mathematics

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“…We have commented this aspect with detail in [23] and we summarize it in Figure 2, where we have plotted the dimensionless quantity Lr 2 in terms of the dimensionless heat flux α 0 Γ, with α 0 ≡ [30] for γ , and from [31] for the ratio γ /γ .…”

Section: Diffusion Contributionmentioning

confidence: 99%

Inhomogeneous vortex tangles in counterflow superfluid turbulence: flow in convergent channels

Saluto¹,

Mongiovı̀

2016

Communications in Applied and Industrial Mathematics

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We investigate the evolution equation for the average vortex length per unit volume L of superfluid turbulence in inhomogeneous flows. Inhomogeneities in line density L and in counterflow velocity V may contribute to vortex diffusion, vortex formation and vortex destruction. We explore two different families of contributions: those arising from a second order expansion of the Vinen equation itself, and those which are not related to the original Vinen equation but must be stated by adding to it second-order terms obtained from dimensional analysis or other physical arguments.

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Evolution of superfluid turbulence in thermal counterflow

Cited by 71 publications

References 30 publications

Laminar, turbulent, or doubly turbulent?

Laminar, turbulent, or doubly turbulent?

Effective thermal conductivity of superfluid helium: laminar, turbulent and ballistic regimes

Inhomogeneous vortex tangles in counterflow superfluid turbulence: flow in convergent channels

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