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...

A two-point, two-time similarity solution is derived for homogeneous decaying turbulence. This the first known which includes temporal decay at two-different times. It assumes that turbulence in all three space dimensions, and finds homogeneity holds across time. The solutions show time logarithmically “stretched” while spatial scales grow. reduces to two point, single equation when times are set equal. initially decays exponentially, then asymptotically as t−n where n≥1 equality possible...

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...

Abstract Identifying and suppressing unknown disturbances to dynamical systems is a problem with applications in many different fields. Here we present model-free method identify suppress an disturbance system based only on previous observations of the under influence known forcing function. We find that, very mild restrictions training function, our able robustly large class disturbances. illustrate scheme identification both deterministic stochastic analog electric chaotic circuit...

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Abstract The influence of surface roughness on the acoustic spectrum in a pulsing restricted flow is investigated over range sizes and conditions. Four different scenarios are introduced, ranging from smooth to relative 0.0486 based hydraulic diameter. These span three restriction severities moderate (56% restricted) severe (82% American Society Echocardiography rating aortic stenosis. distribution energy evaluated, showing that enhanced correlates with higher frequencies (150–300 Hz)...

Abstract A parametric study of the influence flow restriction and Reynolds number on acoustic spectrum is performed. By altering boundary conditions pulsatile flow, changes in frequency coupling can be investigated. To mimic aortic valve stenosis a resting heart, pulsing set to 70 beats per minute (1.17 Hz), while physical size fluid volume pumped altered. An 8 × data matrix collected for different numbers (4500–9831) severity (0–82% restricted), steps based ratings from American Society...

A preliminary study on the effect of stenosis severity in a restricted flow is performed through spectral analysis sound signals. model pulsatile that uses differing area reductions an opening was employed, where contact microphones secured outside reduction measured intensity flow. shows narrowing results increased magnitude frequencies range 15 to 170Hz, with different cases resulting peak frequencies. Low frequency content up 10 Hz remains approximately unchanged. This simplistic approach...

A generalized logarithmic law for high-order moments of passive scalars is proposed turbulent boundary layers. This analogous to the log that has been longitudinal velocity and derived by combining random sweeping decorrelation hypothesis with a spectral model informed attached eddy hypothesis. The theory predicts scalar fluctuations within inertial sublayer will vary logarithmically wall-normal distance ($z$). evaluated using high frequency time-series measurements temperature streamwise...

Abstract A model experiment is used to investigate the relationship between a narrowing in pulsatile flow and relative energy contained measured acoustic spectrum. Inspired by studies of aortic stenosis, this models increasingly severe narrowings an internal with semi-triangular opening mimic shape open tricuspid valve. baseline case attained through use dynamic similarity average unrestricted Normalized spectra for each provides indication frequency band which shows how distribution changes...