Inhomogeneous Structure in High-Speed and High-Number-Density Sprays

2011 ◽  
Author(s):  
Noritsune Kawaharada ◽  
Daisaku Sakaguchi ◽  
Keisuke Komada ◽  
Hironobu Ueki ◽  
Masahiro Ishida
Keyword(s):  
Diesel Fuel ◽  
Time Scale ◽  
High Speed ◽  
Sampling Rate ◽  
Data Sampling ◽  
Integral Time Scale ◽  
Fuel Sprays ◽  
Integral Time ◽  
Data Sampling Rate ◽  
Almost All

A L2F (Laser 2-Focus velocimeter) was applied for the measurements of the velocity and size of droplets in diesel fuel sprays. The micro-scale probe of the L2F has an advantage in avoiding the multiple scattering from droplets in a dense region of fuel sprays. A data sampling rate of 15MHz has been achieved in the L2F system for detecting almost all of the droplets which passed through the measurement probe. Diesel fuel was injected into the atmosphere by using a common rail injector. Measurement positions were located in the planes 15, 20, and 25 mm apart from the injector nozzle exit. Measurement result showed that the integral time scale of turbulence in size was nearly the same as the one in frequency. And the integral time scale of turbulence in velocity was about two times larger than the time scale of size and frequency.

Paper 3: Transient Heat Flow Investigations Using an on-Line Computer

1967 ◽  
Vol 182 (8) ◽  
pp. 42-53
Author(s):  
R. Smyth
Keyword(s):  
Heat Flow ◽  
High Speed ◽  
Sampling Rate ◽  
Digital Data ◽  
Full Description ◽  
Data Sampling ◽  
Experimental Equipment ◽  
Transient Heat Flow ◽  
Control Computer ◽  
On Line

This paper describes some experiences using an on-line computer for transient heat flow investigations. It has been possible to link the experimental equipment to the core of a small high-speed digital computer by way of a multiplexer arrangement which enabled the output of several sensors attached to the experimental equipment to be monitored, sampled, and stored in the computer core at an exceptionally fast rate. It has been shown that, provided access can be had to such a computer installation, it is possible to accurately investigate the output of thermocouples which have a time constant of less than 0·25 μs. The sampling rate ensures that frequency components above 10 kc/s in the transient heat flow phenomena can be accounted for. The use of on-line data sampling, described in this paper, ensures that the laborious and time-consuming task of retrieving data from, say, film records or ultra-violet records, can be rejected as well as the effort of transferring such data to a medium suitable for input to a high-speed digital data-processing computer with the possibility of accompanying errors involved owing to manual handling of the data. The use of multi-channel inputs to the control computer set-up ensures that a maximum of 64 signals can be accommodated simultaneously (although only five are described), and with the sample rates resulting from the use of the on-line equipment, it provides a means of monitoring phenomena such as shock propagations, flame propagations, etc., which might otherwise have been impossible within the accuracy range desirable. A full description is given of the requirements of the auxiliary equipment necessary for the investigation of transient heat flow using the control computer.

scholarly journals Effect of Sampling Rate on Photovoltaic Self-Consumption in Load Shifting Simulations

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5393
Author(s):  
Philippe Voinov ◽  
Patrick Huber ◽  
Alberto Calatroni ◽  
Andreas Rumsch ◽  
Andrew Paice
Keyword(s):  
Sampling Rate ◽  
Smart Meter ◽  
Data Sampling ◽  
Load Shifting ◽  
Consumption Data ◽  
Data Sampling Rate ◽  
Potential Improvement ◽  
Using Data ◽  
The Uk ◽  
The Impact

Grid-connected photovoltaic (PV) capacity is increasing and is currently estimated to account for 3.0% of worldwide energy generation. One strategy to balance fluctuating PV power is to incentivize self-consumption by shifting certain loads. The potential improvement in the amount of self-consumption is usually estimated using smart meter and PV production data. Smart meter data are usually available only at sampling frequences far below the Nyquist limit. In this paper we investigate how this insufficient sampling rate affects the estimated self-consumption potential of shiftable household appliances (washing machines, tumble dryers and dishwashers). We base our analyses on measured consumption data from 16 households in the UK and corresponding PV data. We found that the simulated results have a marked dependence on the data sampling rate. The amount of self-consumed energy estimated with data sampled every 10 min was overestimated by 30–40% compared to estimations using data with 1 min sampling rate. We therefore recommend to take this factor into account when making predictions on the impact of appliance load shifting on the rate of self-consumption.

Impact Analysis of Guidance Instrument Error Separation Accuracy on Sampling Rate of Inertial Navigation Equipment

2013 ◽  
Vol 341-342 ◽  
pp. 880-886
Author(s):  
Wen Jun Wang ◽  
Xiao Jun Duan ◽  
Ju Bo Zhu
Keyword(s):  
Impact Analysis ◽  
Sampling Rate ◽  
Inertial Navigation ◽  
Optimal Sampling ◽  
Data Sampling ◽  
Instrument Error ◽  
Error Separation ◽  
Data Sampling Rate ◽  
Simulation Results ◽  
Navigation Equipment

Based on the linear model of guidance instrument error separation, study on the separation accuracy affected by data sampling rate of inertial navigation equipment. First, theoretically proved that the higher data sampling rate is, the higher separation accuracy we can get. Second, a method for determining the optimal sampling rate is presented, whose idea is from the model itself. At last, the simulation results can verify the above two conclusions.

Effects of Data Sampling Rate on Pattern Recognition Analysis of FT-IR Interferograms

1992 ◽  
Vol 46 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Gary W. Small ◽  
Scott E. Carpenter
Keyword(s):  
Pattern Recognition ◽  
Sampling Rate ◽  
Data Sampling ◽  
Monitoring Applications ◽  
Data Sampling Rate ◽  
Ft Ir ◽  
Pattern Recognition Analysis ◽  
Improved Performance ◽  
Mixture Samples ◽  
The Impact

Fourier transform infrared (FT-IR) data of pure and mixture samples of benzene and nitrobenzene are used to investigate and improve methods for interferogram-based qualitative analyses. For use in dedicated monitoring applications, the methodology employed is based on the application of pattern recognition analysis to short, digitally filtered interferogram segments. In the work described here, the impact of the interferogram data sampling rate on the analysis is studied. The results of this study indicate that optimal pattern recognition prediction performance is achieved by use of linear discriminants developed from faster sampled interferogram data. These findings suggest that improved performance can be obtained in FT-IR monitoring applications through the use of spectrometer designs based on a decreased interferogram scan length, coupled with faster sampling electronics.

scholarly journals 094 Towards objective testing in parkinson’s disease: a systematic review of the literature looking at assessment of postural sway

2019 ◽  
Vol 90 (e7) ◽  
pp. A30.2-A30
Author(s):  
Wenbo Ge ◽  
Deborah Apthorp ◽  
Christian J Lueck ◽  
Hanna Suominen
Keyword(s):  
Systematic Review ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Postural Sway ◽  
Sampling Rate ◽  
Objective Measure ◽  
Data Sampling ◽  
Data Sampling Rate ◽  
Objective Marker

IntroductionParkinson’s Disease (PD) is associated with increased mortality and reduced quality of life. There is currently no accurate objective measure for use in diagnosis or assessment of severity. Analysis of postural sway may help in this regard. This systematic review aimed to assess the effectiveness of the various features currently used to analyse postural sway.MethodsFive databases were searched for articles that examined postural sway in both PD patients and controls. An effect size (ES) was derived for every feature reported in each article. The most effective features and feature-families were determined, along with the influence on these measures of data sampling rate and experimental condition.Results441 papers were initially retrieved, of which 31 met the requirements for analysis. The most commonly-used features were not the most effective (e.g. PathLength had an ES of 0.47 while TotalEnergy had an ES of 1.78). Decreased sampling rate was associated with decreased ES (e.g. ES of PathLength lowered from 1.12 at 100 Hz to 0.40 at 10 Hz). Being off medication was associated with a larger ES (e.g. ES of PathLength was 0.21 on medication and 0.83 off medication).ConclusionsSome measures of postural sway are better able to distinguish PD patients from controls than others. ES is enhanced by using a higher sampling rate and studying patients off medication. These results will inform future studies looking at postural sway in PD and contribute to the aim of finding an objective marker of the disease.

scholarly journals On the Evolution of the Integral Time Scale within Wind Farms

Energies ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 93 ◽  
Author(s):  
Huiwen Liu ◽  
Imran Hayat ◽  
Yaqing Jin ◽  
Leonardo Chamorro
Keyword(s):  
Time Scale ◽  
Wind Farms ◽  
Integral Time Scale ◽  
Integral Time

Effects of data sampling rate on image quality in fan-beam CT system

1985 ◽  
Vol 16 (2) ◽  
pp. 77-84
Author(s):  
Aklra Iwata ◽  
Nobutoshi Yamagishi ◽  
Nobuo Suzumura ◽  
Isao Horiba
Keyword(s):  
Image Quality ◽  
Sampling Rate ◽  
Data Sampling ◽  
Data Sampling Rate ◽  
Ct System

CALCULATION OF ENGINE PARAMETERS USING RECONFIGURABLE HARDWARE

2014 ◽  
Vol 11 (supp01) ◽  
pp. 1344011
Author(s):  
J. BANKS ◽  
N. A. KELSON ◽  
H. MACINTOSH ◽  
M. DAGG ◽  
R. HAYWARD ◽  
...  
Keyword(s):  
Real Time ◽  
Combustion Engine ◽  
Sampling Rate ◽  
Reconfigurable Hardware ◽  
Data Sampling ◽  
Real Time Processing ◽  
Calculation Of Parameters ◽  
Field Programmable ◽  
Data Sampling Rate ◽  
Time Calculation

The feasibility of real-time calculation of parameters for an internal combustion engine via reconfigurable hardware implementation is investigated as an alternative to software computation. A detailed in-hardware field programmable gate array (FPGA)-based design is developed and evaluated using input crank angle and in-cylinder pressure data from fully instrumented diesel engines in the QUT Biofuel Engine Research Facility (BERF). Results indicate the feasibility of employing a hardware-based implementation for real-time processing for speeds comparable to the data sampling rate currently used in the facility, with acceptably low level of discrepancies between hardware and software-based calculation of key engine parameters.

scholarly journals Turbulent dispersion properties from a model simulation of the western Mediterranean

2013 ◽  
Vol 10 (4) ◽  
pp. 1099-1125
Author(s):  
H. Nefzi ◽  
D. Elhmaidi ◽  
X. Carton
Keyword(s):  
Time Scale ◽  
Model Simulation ◽  
Western Mediterranean ◽  
Turbulent Dispersion ◽  
Chaotic Advection ◽  
Relative Dispersion ◽  
Integral Time Scale ◽  
Dispersion Properties ◽  
Integral Time ◽  
Relative Diffusivity

Abstract. Using a high resolution primitive equation model of the western Mediterranean Sea, we analyzed the dispersion properties of a set of homogeneously distributed, passive particle pairs. These particles were initially separated by different distances D0 (D0 = 5.55, 11.1 and 16.5 km), and were seeded in the model at initial depths of 44 and 500 m. This realistic ocean model, which reproduces the main features of the regional circulation, puts in evidence the three well-known regimes of relative dispersion. The first regime due to the chaotic advection at small scales, lasts only a few days (3 days at 44 m depth, a duration comparable with the integral time scale) and the relative dispersion is then exponential. In the second regime, extending from 3 to 20 days, the relative dispersion has a power law tα where α tends to 3 as D0 becomes small. In the third regime, a linear growth of the relative dispersion is observed starting from the twentieth day. For the relative diffusivity, the D2 growth is followed by the Richardson regime D4/3. At large scales, where particle velocities are decorrelated, the relative diffusivity is constant. At 500 m depth, the integral time scale increases (> 4 days) and the intermediate regime becomes narrower than that at 44 m depth due to weaker effect of vortices (this effect decreases with depth). The turbulent properties become less intermittent and more homogeneous and the Richardson law takes place.

Influence of the Lagrangian Integral Time Scale Estimation in the Near Wall Region on Particle Deposition

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Grégory Lecrivain ◽  
Uwe Hampel
Keyword(s):  
High Temperature ◽  
Particle Tracking ◽  
Time Scale ◽  
Particle Deposition ◽  
Normal Component ◽  
Turbulent Dispersion ◽  
Primary Circuit ◽  
Wall Region ◽  
Integral Time Scale ◽  
Integral Time

In a high temperature pebble-bed reactor core where thousands of pebbles are amassed, the friction between the outer graphite layer of the fuel elements triggers the formation of carbonaceous dust. This dust is eventually conveyed by the cooling carrier phase and deposits in the primary circuit of the high temperature reactor. The numerical prediction of carbonaceous dust transport and deposition in turbulent flows is a key safety issue. Most particle tracking procedures make use of the Lagrangian integral time scale to reproduce the turbulent dispersion of the discrete phase. In the present Lagrangian particle tracking procedure, the effect of the Lagrangian integral time scale near the wall is thoroughly investigated. It is found that, in the linear sublayer, a value of the normalized wall normal component of the Lagrangian integral time scale lower that 4 delivers accurate particle deposition velocities. The value worked out here near the wall region is in accordance with Lagrangian integral time scales derived from recent direct numerical simulations.

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