P.-E. Roche
YOU?
Author Swipe
Disentangling temperature and Reynolds number effects in quantum turbulence Open
The interplay between viscous and frictional dissipation is key to understanding quantum turbulence dynamics in superfluid 4 He. Based on a coarse-grained two-fluid description, an original scale-by-scale energy budget that identifies each…
View article: Flight quotas outperform focused mitigation strategies in reducing the carbon footprint of academic travel
Flight quotas outperform focused mitigation strategies in reducing the carbon footprint of academic travel Open
The carbon footprint of academia has become a prominent concern and a burgeoning research area, with a notable focus on greenhouse gas emissions (GHG) from research-related travels. Mitigation strategies often promote alternatives, such as…
Second sound resonators and tweezers as vorticity or velocity probes: Fabrication, model, and method Open
An analytical model of open-cavity second sound resonators is presented and validated against simulations and experiments in superfluid helium using a new resonator design that achieves unprecedented resolution. The model incorporates diff…
Spatial distribution of the quantized vortices' tangle in thermally driven round jets of superfluid helium Open
Thermally driven flows of superfluid 4He display unique features, often related to the presence of quantized vortices—line singularities embedded in the liquid. Here, we focus on turbulent round jets, experimentally investigated using the …
Traveling for academic research : patterns, determinants and mitigation options Open
In the midst of climate change, academic travels - one salient aspect of the carbon footprint of research activities - are at the center of a growing concern. Mitigation options often focus on two dimensions : (i) decreasing the frequency …
Second sound resonators and tweezers as vorticity or velocity probes : fabrication, model and method Open
An analytical model of open-cavity second sound resonators is presented and validated against simulations and experiments in superfluid helium using a new resonator design that achieves unprecedented resolution. The model incorporates diff…
An open-source tool to assess the carbon footprint of research Open
The scrutiny over the carbon footprint of research and higher education has increased rapidly in the last few years. This has resulted in a series of publications providing various estimates of the carbon footprint of one or several resear…
Experimental signature of quantum turbulence in velocity spectra? Open
Velocity measurements in turbulent superfluid helium between co-rotating propellers are reported. The parameters are chosen such that the flow is fully turbulent, and its dissipative scales are partly resolved by the velocity sensors. This…
Local measurement of vortex statistics in quantum turbulence Open
The density fluctuations of quantum vortex lines are measured in a turbulent flow of superfluid He, at temperatures corresponding to superfluid fractions of 16%, 47% and 81%. The probe is a micro-fabricated second sound resonator allowing …
Cooling with a subsonic flow of quantum fluid Open
Miniature heaters are immersed in flows of quantum fluid and the efficiency\nof heat transfer is monitored versus velocity, superfluid fraction and time.\nThe fluid is $^4$He helium with a superfluid fraction varied from 71% down to\n0% an…
The ultimate state of convection: a unifying picture of very high Rayleigh numbers experiments Open
The long-standing puzzle of diverging heat transport measurements at very high Rayleigh numbers (Ra) is addressed by a simple model based on well-known properties of classical boundary layers. The transition to the ‘ultimate state’ of conv…
Nano-shaped hot-wire for ultra-high resolution anemometry in cryogenic helium Open
We present the principle, modeling, and the first implementation of a new type of high resolution hot-wire anemometer designed to operate at cryogenic temperatures and very high Reynolds numbers. Its spatial resolution of a few micrometers…
A local sensor for joint temperature and velocity measurements in turbulent flows Open
We present the principle for a micro-sensor aimed at measuring local correlations of turbulent velocity and temperature. The operating principle is versatile and can be adapted for various types of flow. It is based on a micro-machined can…
View article: Disproportionate entrance length in superfluid flows and the puzzle of counterflow instabilities
Disproportionate entrance length in superfluid flows and the puzzle of counterflow instabilities Open
International audience