Search arXiv⌕ Search

arXiv · 2610.15462

Local sensing of gas microflows using a levitated nanoparticle

Abstract

Local measurements of gas flow in microscale geometries remain challenging due to the difficulty of micromechanical sensors implantation. Here, we use a levitated nanoparticle as a minimally invasive probe to map, with high spatial resolution, both the local pressure and velocity gas flow for a canonical example - a micropipe subjected to a pressure gradient. This technique enables characterization of nonequilibrium gas transport across several flow regimes, from slip flow to free-molecular flow. We directly observe the emergence of a nonlinear pressure distribution at large pressure ratios and obtain agreement with kinetic-theory predictions and Direct Simulation Monte Carlo calculations. These results introduce levitated nanoparticles as powerful and reconfigurable probes for microchannel gas sensing, with applications in microtechnology, micro-chemistry, and bioengineering.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Maxime Debiossac, David Grass, Daniel R. Ladiges, John E. Sader, Markus Aspelmeyer, Nikolai Kiesel. 2026-10-11. Local sensing of gas microflows using a levitated nanoparticle. https://arxiv.org/abs/2610.15462

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

An Omni-Temporal Framework for Hydrodynamic Dispersion and Reaction in Porous Media

Many applications involve porous-media transport driven on time scales comparable to the pore-scale diffusion time, for which classical pseudo-steady dispersion models based on time-invariant transport coefficients may become inaccurate. While frequency-dependent dispersion has been studied in non-reactive porous media, a corresponding framework that simultaneously accounts for advection, diffusion, and heterogeneous interfacial reaction remains lacking. We address this gap by introducing an omni-temporal framework based on volume averaging of the frequency-domain pore-scale advection-diffusion equation subject to a Robin boundary condition spanning the full range of interfacial reactivity. The resulting upscaled formulation yields four frequency-dependent transfer functions: a dispersion tensor, an advection-suppression vector, a spectral Sherwood number, and a reactivity-bias vector, with the reactivity-bias vector introduced here for the first time. Analytical solutions for fully developed flow between parallel plates and through circular tubes reveal distinct kinetics- and diffusion-limited regimes, including capacitive and semi-infinite Warburg-type frequency responses. Comparisons of transient breakthrough curves with direct numerical simulations demonstrate substantial improvement over conventional pseudo-steady dispersion, particularly for short-duration pulses. Application to a periodic array of square rods under cross flow further demonstrates the frameworks applicability beyond canonical geometries.

physics.flu-dyn↗

Comparative Numerical Study of Film Cooling Strategies for Thermal Protection of a Kerosene-Fueled Oblique Detonation Combustor

Thermal protection remains a major challenge for oblique detonation engines (ODEs), whose combustors combine intense heat release, anchored on oblique detonation waves (ODWs). This study numerically investigates the effects of coolant type and mass flow rate on the flow structure, thermal environment and propulsion performance of a film-cooled kerosene-air ODE combustor at Mach 10 and 15 km altitude. Three active cooling strategies are compared under identical conditions: air film cooling, gaseous-kerosene film cooling, and liquid-kerosene mist cooling. Stable, wall-attached oblique-detonation propagation and the canonical wave structure are maintained, with the wave-coolant interaction depending systematically on the coolant medium. Air injection causes the greatest disturbance to the initiation region and downstream wave interactions, yielding the largest propulsion penalty. The cooling strategies substantially reduce the near-wall thermal load but produce distinct wall-temperature distributions. Gaseous-kerosene cooling yields a spatially periodic response from the discrete injection slots, whereas liquid-kerosene mist cooling gives a smoother and lower near-wall temperature through two-phase mixing and phase-change heat absorption. Liquid-kerosene mist cooling provides the most favorable balance between thermal protection and propulsion performance at low to moderate injection levels. With further increases in injection level, the thermal benefit approaches saturation while the propulsion penalty continues to grow: the mean near-wall fluid temperature reduction remains about 87% across both the inter-slot and cooling-slot wall segments, whereas the total specific impulse is reduced by about 3%-5%. These results quantify the thermal-propulsive trade-off across film-cooling media and demonstrate the potential of fuel-based cooling for thermal management in hypersonic ODE combustors.

physics.flu-dyn↗

Two-Way Coupled Dynamics of Quantized Vortex Bundle Formation in Spatially Periodic Normal-Fluid Turbulence

Using fully coupled two-way simulations combining the vortex filament model with the Navier--Stokes equations, we discover that quantized vortices in superfluid $^4$He are systematically rolled up into coherent bundles within normal-fluid vortex tubes. Although co-rotating quantized vortices do not aggregate spontaneously, mutual friction with the normal fluid actively drives their bundling, directly inheriting the spatial hierarchy of classical turbulence. Mutual friction excites high-wavenumber normal-fluid vortex tubes adjacent to quantized vortices, while the superfluid forms a nested structure of thick low-wavenumber outer tubes and fine high-wavenumber inner tubes around the vortex lines. A distinct time lag between superfluid kinetic energy and dissipation fuels the energy cascade, giving rise to Kolmogorov's $k^{-5/3}$ spectrum. Crucially, bundle lifetimes are governed by the ratio of the local coupling time scale $t_\mathrm{cl}$ to the Kolmogorov dissipation time scale $τ_η$ ($t_\mathrm{cl}/τ_η< 20$), leading to enhanced thermal stability at higher temperatures. These findings establish a unified mechanism for two-fluid multiscale vortex organization.

physics.flu-dyn↗