Adrian Melling

Bio: Adrian Melling is an academic researcher from University of Erlangen-Nuremberg. The author has contributed to research in topics: Water vapor & Spectrometer. The author has an hindex of 9, co-authored 18 publications receiving 3035 citations.

Tracer particles and seeding for particle image velocimetry

Abstract: The size specifications for suitable tracer particles for particle image velocimetry (PIV), particularly with respect to their flow tracking capability, are discussed and quantified for several examples. A review of a wide variety of tracer materials used in recent PIV experiments in liquids and gases indicates that appropriately sized particles have normally been used. With emphasis on gas flows, methods of generating seeding particles and for introducing the particles into the flow are described and their advantages are discussed.

Principles and practice of laser-Doppler anemometry

Abstract: Keywords: anemometrie a : laser ; anemometrie ; optique ; laser : Doppler Reference Record created on 2005-11-18, modified on 2016-08-08

Principles and practice of laser-Doppler anemometry

Abstract: Keywords: anemometrie a : laser ; anemometrie ; optique ; laser : Doppler Reference Record created on 2005-11-18, modified on 2016-08-08

Interpolation Correlations for Fluid Properties of Humid Air in the Temperature Range 100 °C to 200 °C

Abstract: This paper provides simple analytical correlations for selected thermodynamic and fluid transport properties for the mixture dry air and water vapor. These correlations are derived from theory as well as from numerical fitting procedures and give expressions for density ϱ, viscosity μ, thermal conductivity k, specific heat cp, and Prandtl number Pr at a working pressure of p=1 bar and for a temperature range from 100 °C to 200 °C. The main purpose is to present a comparatively simple set of equations, as the correlations do not reflect in every case the underlying physical background. Since experimental data are scarce for the properties under investigation, it was in some cases necessary to extrapolate the available correlations to temperatures or water vapor contents where no experimental data could be found. The derived equations are compared with the pure component values for dry air and water vapor and, as far as possible, also for air-water vapor mixtures.

Thermophoresis of particles in a heated boundary layer

Abstract: A laser-Doppler velocimeter (LDV) study of velocity profiles in the laminar boundary layer adjacent to a heated flat plate revealed that the seed particles used for the LDV measurements were driven away from the plate surface by thermophoretic forces, causing a particle-free region within the boundary layer of approximately one half the boundary-layer thickness. Measurements of the thickness of this region were compared with particle trajectories calculated according to several theories for the thermophoretic force. It was found that the theory of Brock, with an improved value for the thermal slip coefficient, gave the best agreement with experiment for low Knudsen numbers, λ/R = O(10−1), where λ is the mean free path and R the particle radius.Data obtained by other experimenters over a wider range of Knudsen numbers are compared, and a fitting formula for the thermophoretic force useful over the entire range 0 [les ] λ/R [les ] ∞ is proposed which agrees within 20% or less with the majority of the available data.

Tomographic particle image velocimetry

Abstract: This paper describes the principles of a novel 3D PIV system based on the illumination, recording and reconstruction of tracer particles within a 3D measurement volume The technique makes use of several simultaneous views of the illuminated particles and their 3D reconstruction as a light intensity distribution by means of optical tomography The technique is therefore referred to as tomographic particle image velocimetry (tomographic-PIV) The reconstruction is performed with the MART algorithm, yielding a 3D array of light intensity discretized over voxels The reconstructed tomogram pair is then analyzed by means of 3D cross-correlation with an iterative multigrid volume deformation technique, returning the three-component velocity vector distribution over the measurement volume The principles and details of the tomographic algorithm are discussed and a parametric study is carried out by means of a computer-simulated tomographic-PIV procedure The study focuses on the accuracy of the light intensity field reconstruction process The simulation also identifies the most important parameters governing the experimental method and the tomographic algorithm parameters, showing their effect on the reconstruction accuracy A computer simulated experiment of a 3D particle motion field describing a vortex ring demonstrates the capability and potential of the proposed system with four cameras The capability of the technique in real experimental conditions is assessed with the measurement of the turbulent flow in the near wake of a circular cylinder at Reynolds 2,700

Tracer particles and seeding for particle image velocimetry

Abstract: The size specifications for suitable tracer particles for particle image velocimetry (PIV), particularly with respect to their flow tracking capability, are discussed and quantified for several examples. A review of a wide variety of tracer materials used in recent PIV experiments in liquids and gases indicates that appropriately sized particles have normally been used. With emphasis on gas flows, methods of generating seeding particles and for introducing the particles into the flow are described and their advantages are discussed.

Theory and design for mechanical measurements

Abstract: The assignment of numerical values to physical quantities underlies all quantitative statements in engineering and the physical sciences. This assignment is achieved by the process of measurement. The physical quantity being measured and the precision required in the numerical value determines the instrumentation to be used. The design of a measurement system therefore involves the analysis of the attribute to be measured, the means available for its detection and the verification that the measurement system performs as intended and can achieve the desired accuracy and precision. In this book Figliola and Beasley first discuss in general terms the basics of measurement, analogue and digital data acquisition systems and signal processing, the statistics of measurement and the analysis of error and uncertainty. In successive chapters they concentrate on the instruments and their physical basis in the areas of electricity, temperature, fluid flow, elastic strain and mechanics (displacement, motion, force and power). The coverage is directed towards measurements in various branches of engineering, with numerous worked examples and problems for students (approximately 30 to 40) at the end of each chapter. Since it is an American engineering text, the book uses both SI and English units. Unfortunately, the text is flawed by numerous errors. Some of the more egregious are that in chapter 1, `dimension' is used in place of `unit', the definitions given for the ampere and the ohm are in terms of `international' units that were abandoned in 1948 and derived units are expressed, for example, as `' in place of the standard forms (SI, ISO, ANSI) of `' or `'. There are furthermore numerous minor numerical errors and inconsistencies. One of the more serious flaws is the failure to distinguish between bias errors and uncertainty due to bias in the discussion of chapter 5. There is also a misuse of the student in the evaluation of uncertainty (although this error is not exclusively Figliola and Beasley's, since it occurs in ANSI documents on fluid flow measurement). Given the estimate for variance, with degrees of freedom, an uncertainty interval at confidence level p is properly , while the uncertainty for a combined quantity is where is evaluated from the Welch - Satterthwaite expression In spite of its shortcomings, the book collects a great deal of material in one place and, in the hands of a careful instructor who is aware of its flaws, could be useful as a supplementary text on measurement. E Richard Cohen