Part I Theoretical concepts: introduction suboptimal nonlinear filters a tutorial on particle filters Cramer-Rao bounds for nonlinear filtering Part II Tracking applications: tracking a ballistic object bearings-only tracking range-only tracking bistatic radar tracking tracking targets through blind Doppler terrain aided tracking detection and tracking of stealthy targets group and extended object tracking

Beyond the Kalman Filter: Particle Filters for Tracking Applications

http://experimentationlab.berkeley.edu/sites/default/files/AFMImages/butt_AFM.pdf

Force measurements with the atomic force microscope: Technique, interpretation and applications

to be done in this area. Face recognition is a problem that scarcely clamoured for attention before the computer age but, having surfaced, has involved a wide range of techniques and has attracted the attention of some fine minds (David Mumford was a Fields Medallist in 1974). This singular application of mathematical modelling to a messy applied problem of obvious utility and importance but with no unique solution is a pretty one to share with students: perhaps, returning to the source of our opening quotation, we may invert Duncan's earlier observation, 'There is an art to find the mind's construction in the face!'.

Linear and nonlinear waves, by G. B. Whitham. Pp.636. £50. 1999. ISBN 0 471 35942 4 (Wiley).

This book describes and explains the fundamental physical processes involved in bubble dynamics and the phenomenon of cavitation. It is intended as a combination of a reference book for those scientists and engineers who work with cavitation or bubble dynamics and as a monograph for advanced students interested in some of the basic problems associated with this category of multiphase flows. A basic knowledge of fluid flow and heat transfer is assumed but otherwise the analytical methods presented are developed from basic principles.

The book begins with a chapter on nucleation and describes both the theory and observations of nucleation in flowing and non-flowing systems. The following three chapters provide a systematic treatment of the dynamics of the growth, collapse or oscillation of individual bubbles in otherwise quiescent liquids. Chapter 4 summarizes the state of knowledge of the motion of bubbles in liquids. Chapter 5 describes some of the phenomena which occur in homogeneous bubbly flows with particular emphasis on cloud cavitation and this is followed by a chapter summarizing some of the experiemntal observations of cavitating flows. The last chapter provides a review of the free streamline methods used to treat separated cavity flows with large attached cavities.

/pdf/cavitation-and-bubble-dynamics-1vfop84jck.pdf

Cavitation and Bubble Dynamics

The boundary layer equations for plane, incompressible, and steady flow are 

$$\matrix{ {u{{\partial u} \over {\partial x}} + v{{\partial u} \over {\partial y}} = - {1 \over \varrho }{{\partial p} \over {\partial x}} + v{{{\partial ^2}u} \over {\partial {y^2}}},} \cr {0 = {{\partial p} \over {\partial y}},} \cr {{{\partial u} \over {\partial x}} + {{\partial v} \over {\partial y}} = 0.} \cr }$$

Boundary Layer Theory

The effects of tube diameter, coil diameter, helix angle and liquid viscosity on flow patterns, pressure drop and holdup for cocurrent gas-liquid flow in helically coiled tubes have been investigated. Nine coils of varying coil diameter and helix angle have been used with liquids of three different viscosities and air at varying pressures. The effect of tube diameter on pressure drop and holdup was determined by using tubes of diameters up to 2-in.



Flow patterns were adequately predicted for all the systems by Baker's plot. Small helix angles were found to have no effect on pressure drop or holdup in coiled tubes. Both pressure drop and holdup could be adequately correlated using the Lockhart-Martinelli approach with modified correlating parameters.



On a etudie les effets des diametres des tubes et de l'enroulement, de l'angle de l'helice et de la viscosite du liquide sur l'allure de l'ecoulement, la chute de pression et la retenue liquide, dans le cas d'un ecoulement parallele de gaz et liquids dans des tubes pourvus d'un enroulement helicoidal. On a utilise neuf enroulements possedant differents diametres et angles d'helice ainsi que des liquides de trois viscosites distinctes et de l'air a diverses pressions. On a determine l'effet du diametre du tube sur la chute de pression et la retenue liquide au moyen de tubes de deux pouces de diametre. On a pu predire exactement l'allure de l'ecoulement pour tous les systemes au moyen de la courbe de Baker. On a constate que les petits angles d'helice n'exercaient aucun effet sur la chute de pression ou la retenue liquide dans des tubes pourvus d'enroulement. On a pu etablir une correlation satisfaisante entre la chute de pression et la retenue liquide, en utilisant la methode de Lockhart et Martinelli avec modification des parametres de correlation.

Studies on cocurrent gas‐liquid flow in helically coiled tubes. I. Flow patterns, pressure drop and holdup

Mechanisms of heat and mass transport at gas-liquid interfaces

In previous studies, the adsorption kinetics of asphaltenes at the water–oil interface were interpreted utilizing a Langmuir equation of state (EOS) based on droplet expansion experiments.1−3 Long-term adsorption kinetics followed random sequential adsorption (RSA) theory predictions, asymptotically reaching ∼85% limiting surface coverage, which is similar to limiting random 2D close packing of disks. To extend this work beyond this slow adsorption process, we performed rapid contractions and contraction–expansions of asphaltene-laden interfaces using the pendant drop experiment to emulate a Langmuir trough. This simulates the rapid increase in interfacial asphaltene concentration that occurs during coalescence events. For the contraction of droplets aged in asphaltene solutions, deviation from the EOS consistently occurs at a surface pressure value ∼21 mN/m corresponding to a surface coverage ∼80%. At this point droplets lose the shape required for validity of the Laplace–Young equation, indicating solid...

Asphaltene-laden interfaces form soft glassy layers in contraction experiments: a mechanism for coalescence blocking.

A leak detection system for pipelines was developed by using artificial neural networks (ANN) for leak sizing and location and by processing the field data. This system can detect and locate leaks down to 1% of flow rates in pipelines carrying hazardous materials in about 100 s. A reference pipeline was considered for practical implementation of the package. The ability of the package to withstand spurious alarms in the event of operational transients was tested. The compressibility effect, due to packing of the liquid in the pipeline, causes many such spurious alarms. Adequate preprocessing of the data was performed by using a computer code in conjunction with the ANN to compensate for the operational variations and to prevent spurious alarms. The package detects leaks as small as 1% of the inlet flow rate and correctly predicts the leaking segment of pipeline with a probability of success that is greater than 50% for the smallest leak. In all cases, the timely response of the system was seen as a major advantage.

Leak detection in liquefied gas pipelines by artificial neural networks

Rates of gas transfer between air and water remain difficult to predict or simulate due to the wide range of length and time scales and lack of experimental observations of near-surface fluid velocity and gas concentrations. The surface renewal model (SR) and surface divergence model (SD) provide the two leading models of the process, yet they remain poorly tested by observation because near-surface velocity is difficult to measure. To contribute to evaluation of these models, we apply new techniques called interfacial particle imaging velocimetry (IPIV) and three-dimensional IPIV (3D-IPIV) for measuring water velocities within a millimetre of a moving deformable air–water interface. The latter technique (3D-IPIV) simultaneously measures the air–water interface topography. We apply these techniques to turbulent open-channel water flows and wind-sheared water flows with microscale breaking waves. Additional measurements made for each flow condition are bulk turbulent length scales, bulk turbulent velocity scales, air–water gas transfer rates, friction velocities, and wave characteristics. We analyse these data to test the surface divergence models for interfacial gas transfer. The first test is of predictions from the Banerjee (Ninth International Heat Transfer Conference, Keynote Lectures, vol. 1, 1990, pp. 395–418, Hemisphere Press) surface divergence model for gas transfer for homogeneous isotropic turbulence interacting with a planar free surface. The second test is of predictions from the McCready, Vassiliadou and Hanratty (AIChE J., vol. 32(7), 1986, pp. 1108–1115) surface divergence model, as applied in both open-channel flow and wind-sheared wavy flows. We find the predictions of the Banerjee and McCready et al. models to agree with the experimental data taken for open-channel flow conditions. On the other hand, for wind-driven flows with wind waves we find disagreement between the McCready et al. predictions and our direct measurements of the gas transfer coefficient. The cause of the disagreement is investigated by Lagrangian tracking of surface divergence of surface water patches, and by analysis of the corresponding Lagrangian time series with advection–diffusion concepts. A quantitative criterion based on surface divergence strength and lifetime is proposed to distinguish the effectiveness of each near-surface motion toward causing interfacial gas transfer. Capillary waves are found to contribute to surface divergence but to have too short a time scale to cause interfacial gas transfer. As wind speed increases, the presence and intensity on the air–water interface of capillary waves and other ineffective near-surface motions is diminished by the rise of turbulent wakes from microscale breaking waves thus causing the disagreement of the surface divergence model’s predicted transfer rates with measurements. A model of air–water gas transfer that combines the surface renewal and surface divergence models is formulated and found to agree with the data from both open-channel flows and wind-driven flows without requiring an empirical coefficient.

Sanjoy Banerjee

Papers

Studies on cocurrent gas‐liquid flow in helically coiled tubes. I. Flow patterns, pressure drop and holdup

Mechanisms of heat and mass transport at gas-liquid interfaces

Asphaltene-laden interfaces form soft glassy layers in contraction experiments: a mechanism for coalescence blocking.

Leak detection in liquefied gas pipelines by artificial neural networks

Air–water gas transfer and near-surface motions