A5058485644- Fluid Dynamics and Turbulent Flows
- Particle Dynamics in Fluid Flows
- Wind and Air Flow Studies
- Aerodynamics and Acoustics in Jet Flows
- Meteorological Phenomena and Simulations
- Fluid Dynamics and Vibration Analysis
- Aerodynamics and Fluid Dynamics Research
- Surface Modification and Superhydrophobicity
- Fluid Dynamics and Heat Transfer
- Heat Transfer Mechanisms
- Flow Measurement and Analysis
- 2D Materials and Applications
- Aeolian processes and effects
- Tribology and Lubrication Engineering
- Sensor Technology and Measurement Systems
- Graphene research and applications
- Experimental and Theoretical Physics Studies
- Fluid Dynamics and Thin Films
- Biomimetic flight and propulsion mechanisms
- Advanced Sensor Technologies Research
- Advanced Combustion Engine Technologies
- Near-Field Optical Microscopy
- Cardiovascular Health and Disease Prevention
- Plant Surface Properties and Treatments
- Surface and Thin Film Phenomena
California Institute of Technology
2021-2024
Inner Mongolia University of Technology
2023
Columbia University
2022-2023
Stanford University
2020
Villanova University
2020
Princeton University
2016-2019
Results on turbulent skin friction reduction over air- and liquid-impregnated surfaces are presented for aqueous Taylor-Couette flow. The fabricated by mechanically texturing the inner cylinder chemically modifying features to make them either non-wetting with respect water (air-infused, or superhydrophobic case), wetting an oil that is immiscible (liquid-infused case). drag reduction, which remains fairly constant Reynolds number range tested (100 ≤ Reτ 140), approximately 10% surface 14%...
Fully resolved measurements of turbulent boundary layers are reported for the Reynolds number range $Re_{\unicode[STIX]{x1D70F}}=6000{-}20\,000$ . Despite several decades research in wall-bounded turbulence there is still controversy over behaviour streamwise intensities near wall, especially at high numbers. Much it stems from uncertainty measurement due to finite spatial resolution. Conventional hot-wire anemometry limited resolution issues that cause attenuation intensity profile wall. To...
Abstract Simulations and experiments at low Reynolds numbers have suggested that skin-friction drag generated by turbulent fluid flow over a surface can be decreased oscillatory motion in the surface, with amount of reduction predicted to decline increasing number. Here, we report direct measurements substantial achieved using spanwise oscillations high friction ( $${{{\mathrm{Re}}}_{\tau }}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>Re</mml:mi>...
Abstract Ferroelectricity, a spontaneous and reversible electric polarization, is found in certain classes of van der Waals (vdW) materials. The discovery ferroelectricity twisted vdW layers provides new opportunities to engineer spatially dependent optical properties associated with the configuration moiré superlattice domains network domain walls. Here, we employ near-field infrared nano-imaging nano-photocurrent measurements study minimally WSe 2 . ferroelectric are visualized through...
Liquid-infused surfaces present a novel, passive method of turbulent drag reduction. Inspired by the Nepenthes Pitcher Plant, liquid-infused utilize lubricating fluid trapped within structured roughness to facilitate slip at effective surface. The conceptual idea is similar that superhydrophobic surfaces, which rely on air layer, whereas use preferentially wetting liquid lubricant create localized fluid–fluid interfaces. Maintaining presence these slipping interfaces has been shown be an...
Here, we present measurements of turbulent drag reduction in boundary layers at high friction Reynolds numbers the range $4500 \le Re_\tau 15000$. The efficacy approach, using streamwise travelling waves spanwise wall oscillations, is studied for two actuation regimes: (i) inner-scaled (ISA), as investigated Part 1 this study, which targets relatively high-frequency structures near-wall cycle, and (ii) outer-scaled (OSA), was recently presented by Marusic et al. (Nat. Commun., vol. 12, 2021)...
Gas diffusion rates in and out of superhydrophobic surfaces transitional turbulent boundary layers are observed measured at varying Reynolds numbers, pressures, dissolved gas concentrations. Results show a power-law correlation between the Sherwood friction number.
Direct numerical simulations of two superposed fluids in a channel with textured surface on the lower wall have been carried out. A parametric study varying viscosity ratio between has performed to mimic both idealised super-hydrophobic and liquid-infused surfaces assess its effect frictional, form total drag for three different geometries: longitudinal square bars, transversal bars staggered cubes. The interface is assumed be slippery streamwise spanwise directions not deformable vertical...
Turbulent drag reduction through streamwise travelling waves of spanwise wall oscillation is investigated over a wide range Reynolds numbers. Here, in Part 1, wall-resolved large-eddy simulations channel flow are conducted to examine how the frequency and wavenumber wave influence at friction numbers $Re_\tau = 951$ $4000$. The actuation parameter space restricted inner-scaled (ISA) pathway, where achieved direct attenuation near-wall scales. level turbulence attenuation, hence reduction,...
Abstract Cardiovascular disease is the leading cause of death worldwide. Existing methods for continuous, noninvasive blood pressure (BP) monitoring suffer from poor accuracy, uncomfortable form factors, or a need frequent calibration, limiting their adoption. We introduce new framework continuous BP measurement that and calibration-free called resonance sonomanometry. The method uses ultrasound imaging to measure both arterial dimensions artery wall resonances are induced by acoustic...
Abstract The ability to perform nanometer‐scale optical imaging and spectroscopy is key deciphering the low‐energy effects in quantum materials, as well vibrational fingerprints planetary extraterrestrial particles, catalytic substances, aqueous biological samples. These tasks can be accomplished by scattering‐type scanning near‐field microscopy (s‐SNOM) technique that has recently spread many research fields enabled notable discoveries. Herein, it shown s‐SNOM, together with probe general,...
Antimicrobial resistance (AMR) causes millions of illnesses every year, threatening the success lifesaving antibiotic therapy and, thus, public health. To examine rise and spread antimicrobial around world, our study performs a multivariate statistical analysis gene data from eight different countries: US, UK, China, Brazil, Mexico, Canada, Australia, South Africa. Multi-dimensional points were projected onto two-dimensional plane using principal component organized into dendrogram utilizing...
To control and navigate micro air vehicles (MAVs) efficiently, there is a need for small, lightweight, durable, sensitive, fast, low-power airspeed sensors. When designing sensors to meet these requirements, soft materials are promising alternatives more traditional due the large deformations they can withstand. In this article, new concept of material flow sensor presented based on elastic filament velocimetry, which fulfills all necessary criteria. This technique measures velocity by...
A novel method for velocity measurements in both gaseous and liquid flows is presented. The sensing element comprised of a free-standing electrically conductive nanoscale ribbon suspended between silicon supports. Due to its minuscule size, the nanoribbon deflects flow due viscously dominated fluid forcing inducing an axial strain element. leads resistance change, which measurable through simple Wheatstone bridge circuit can be related semi-analytic analysis. Two methods characterization are...
We present a new particle tracking algorithm for accurately resolving large deformation and rotational motion fields, which takes advantage of both local global algorithms. call this method ScalE Rotation Invariant Augmented Lagrangian Particle Tracking (SerialTrack). This builds an iterative scale rotation invariant topology-based feature vector each within multi-scale algorithm. The kinematic compatibility condition is applied as augmented constraint to enhance accuracy. An open source...
This contribution reviews recent advances in the possible identification of blazars as potential sources at least some very-high-energy neutrinos detected by IceCube neutrino detector South Pole. The basic physical requirements for production and physics constraints that may be drawn from - blazar associations are reviewed. Several individual cases will discussed more detail. It is emphasized due to $\gamma\gamma$ opacity efficiently neutrino-producing blazars, an association between X-ray...
Moir\'e superlattices in twisted two-dimensional materials have generated tremendous excitement as a platform for achieving quantum properties on demand. However, the moir\'e pattern is highly sensitive to interlayer atomic registry, and current assembly techniques suffer from imprecise control of average twist angle, spatial inhomogeneity local distortions due random strain. Here, we demonstrate new way manipulate patterns hetero- homo-bilayers through in-plane bending monolayer ribbons,...
A novel method of obtaining two orthogonal velocity components with high spatial and temporal resolution is investigated. Both are obtained utilizing a single sensing nanoribbon by combining the independent operating modes classic hot wire anemometry newly discovered elastic filament velocimetry (EFV). In contrast to anemometry, EFV measures fluid through correlating forcing internal strain wire. order utilize both operation, system that switches between built characterized, theoretically...