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Crude Unit Column Overhead – Corrosion Water is usually injected in the overhead piping to: • Help quench and scrub the overhead vapors • Dilute acids formed • Prevent any salts or acids from forming in the system

Turbulence of the round jet has been assessed using invariants of the velocity gradient tensor. Experimental data, obtained using Tomographic Particle Image Velocimetry (Tomo-PIV), using four PCO-4000 cameras with 11 megapixel resolution, is presented for a seeded free air jet, operating in the turbulent regime and the Re number based on the diameter of the nozzle is 10000. Using the acquired 3-D velocity fields, the local statistical and geometrical structure of three-dimensional turbulent flow can be described by properties of the velocity gradient tensor. The invariants of the velocity gradient (R and Q), rate-of-strain ( Rs andQs ), and rate-of-rotation (Qw ) tensors are analyzed across the turbulent expanding regions at different distances from the nozzle outlet. More specifically, the JPDF of invariants is computed, which allows a detailed statistical characterization of the dynamics, geometry and topology of the flow during the entrainment process. It should be noted that the results obtained are indicative of the preliminary work in this area.

The motion tracking enhancement technique (MTE) is a recently introduced method to improve the accuracy of tomographic PIV measurements at seeding density higher than currently practiced. The working principle is based on the fact that the particle field and its projections are correlated between the two exposures. Therefore, information from subsequent exposures can be shared within the tomographic reconstruction process of a single object, which largely reduces the energy lost into ghost particles. The study follows a previous work based on synthetic particle images, showing that the MTE technique has an effect similar to that of increasing the number of cameras. In the present analysis, MTE is applied to Tomographic PIV data from two time-resolved experiments on turbulent shear flows: a round jet at Re = 5,000 (facq = 1,000 Hz) and a turbulent boundary layer at the trailing edge of an airfoil (Rec = 370,000) measured at 12,000 Hz. The application of MTE is extended to the case of more than two recordings. The performance is assessed comparing the results from a lowered number of cameras with respect to the full tomographic imaging system. The analysis of the jet flow agrees with the findings of numerical simulations provided the results are scaled taking into account the concept of MTE efficiency based on the volume fraction where ghost-pairs (Elsinga et al. 2010a) are produced.

To apply Tomographic PIV to industrial flow, ex. flow around rain gutter, 50 mm volume thickness and 0.1 ppp particle density, at least, are necessary. In such experimental conditions, signal to ghost ratio of object images and accuracy of vectors are problems. To tackle these problems, influence of number of cameras, image pre-processing and vector post-processing to the accuracy of Tomographic PIV are experimentally investigated at different measurement volume thickness and particle densities. This investigation reveals that time-series minimum subtraction at each pixel without any spatial filter is suitable for image pre-processing for such conditions. Although this filter results in lower signal to ghost ratio, better vector field without less spurious vectors than a traditional one. This signal to ghost ratio is improved linearly by increasing the number of camera up to 8 and accuracy of velocity vectors also increasing up to 8 at any particle density and volume thickness conditions. This improvement by increasing the number of camera is experimentally proved as a first time. Obtained velocity vectors are filtered by spatial filter in physical domain and frequency domain to reduce measurement noise. Filtered velocity profile of thick volume measurable domain, 135 x 230 x 50 mm3 in air, is well coincident with previous experiments even in velocity fluctuation and Reynolds stress. To resolve turbulent fine scale vortex and large scale vortex simultaneously, more than 6-camera are needed for the case of 0.12 ppp particle density and 50 mm volume thickness. For the case of 0.45 ppp and 50 mm volume thickness with 8-camera has also enough accuracy to access velocity fluctuation and Reynolds stress. This paper achieves the large measurable domain, 160 x 220 x 80 mm3, at the particle density of 0.53 ppp.

One of the major environmental problems facing the aviation industry is that of aircraft noise. The work presented in this paper, done as part of the EU’s OPENAIR Project, looks at reducing spoiler noise whilst maintaining aerodynamic performance, through means of large-scale fractal porosity. It is hypothesised that the highly turbulent flow generated by fractal grids from the way the multiple-length-scales are organised in space, would reduce the impact of the re-circulation region and with it, the low frequency noise it generates. In its place, a higher frequency noise is introduced which is more susceptible to atmospheric attenuation and is less offensive to the human ear. A total of nine laboratory scaled spoilers were looked at, seven of which had a fractal design, one with a regular grid design and one solid for reference. The spoilers were inclined at an angle of 30. Force, acoustic and flow visualisation experiments on a flat plate were carried out and it was found that the present fractal spoilers reduce the low frequency noise by 2.5dB. Results show that it is possible to improve the acoustic performance by modifying a number of parameters defining the fractal spoiler, some of them very sensitively. From these experiments, two fractal spoilers were chosen for a detailed aero-acoustic study on a three-element wing system, where it was found that the fractal spoilers had a reduction of up to 4dB in the sound pressure level while maintaining similar aerodynamic performances as conventional solid spoilers on the measured wing system.

Particle image velocimetry (PIV) experiments have been carried out to study the correlation between the high- Reynolds number turbulent flow and wall heat transfer characteristics in a two-pass square channel with a smooth wall and a 90
rib-roughened wall. Detailed averaged velocity distributions and turbulent kinetic energy for both the main and the secondary flows are given for a representative Reynolds number (Re) of 30,000. The PIV measurement results were compared with the heat transfer experimental data of Ekkad and Han [International Journal of Heat Mass Transfer 40 (11) (1997) 2525–2537]. The result shows that the flow impingement is the primary factor for the two-pass square channel heat transfer enhancement rather than the flow turbulence level itself. The characteristics of the secondary flow,for example,vortex’s shape, strength,rotating-direction and positions, are closely correlated with the wall heat transfer enhancements for both smooth and ribbed wall two-pass square channels. The rib-induced flow turbulence increases the heat transfer mainly because of the enhanced local flow impingement near the rib.

The flow at Reynolds number 100k around an inflexible, two-dimensional flapping airfoil is investigated using the stereoscopic Particle Image Velocimetry (PIV) technique. The typical phenomenon of a moving laminar separation bubble during one flapping cycle is identified. The measurement data is compared with URANS computations.

The paper presents results of strain measurements in cohesionless sand in two different boundary value problems, namely quasi-static pull-out test of a steel wall and confined granular flow in a rectangular model silo using a non-destructive method called Particle Image Velocimetry (PIV) which is a technique for measuring surface displacements from digital images. Advantages and disadvantages of the method are outlined.

A concept for dynamic mixture formation investigations of fuel/air mixtures is presented which can equally be applied to several other laser induced fluorescence (LIF) applications. Double-pulse LIF imaging was used to gain insight into dynamic mixture formation processes. The setup consists of a modified standard PIV setup. The ‘‘fuel/air ratio measurement by laser induced fluorescence (FARLIF)’’ approach is used for a quantification of the LIF images in order to obtain pairs of 2D fuel/air ratio maps. Two different evaluation concepts for LIF double pulse images are discussed. The first is based on the calculation of the temporal derivative field of the fuel/air ratio distribution. The result gives insight into the dynamic mixing process, showing where and how the mixture is changing locally. The second concept uses optical flow methods in order to estimate the motion of fluorescence (i.e., mixture) structures to gain insight into the dynamics, showing the distortion and the motion of the inhomogeneous mixture field.

The active control of laminar and turbulent flows with dynamic actuators is of great scientific and technological interest in nearly all fields of fluid mechanics. Today, most of the well established actuator concepts are based on pneumatic and micro-mechanic bases. However, owing to their limited dynamic range, their potential seems to be limited from the present point of view [1]. Recently it was successfully demonstrated that a boundary layer flow can be efficiently controlled by using an optical actuator concept, which allows non-intrusive excitation of the flow with nearly any pulse-width and repetition-rate by heating the surface of a model with a short-focused laser pulse [2]. The drawback of the proposed and examined method was the gradual ablation of the model surface. To avoid this problem the excitation was performed above the surface in this investigation [3]. By using the phased locked stereoscopic PIV and Schlieren technique the dynamic effect of the laser induced plasma on a boundary layer flow could be examined in detail. In this contribution the main results will be summarized and the perspective of this actuation method for fundamental and applied fluid mechanics will be outlined.

The active control of laminar and turbulent flows with dynamical actuators is of great scientific and technological interest in nearly any field of fluid mechanics. On on hand it becomes possible to generate artifical flow structures whose properties and significance for the turbulent mixing, or their interaction with other flow structures, can be examined. On the other hand, these devices suppress flow separation on profiles or increase the performance of flow engines. Today, most of the well established actuator concepts are based on pneumatic and micro-mechanic basis. However, owing to their limited dynamic range their potential seems to be limited from the present point of view, see Gad-el-Hak (2001), and also their technical implementation is sometimes difficult. In the following an optical actuator concept is proposed and examined that allows to excite the flow non-intrusively with nearly any pulse-width and repetition-rate.

We report particle image velocimetry measurements of the collision of a vortex ring with a heated wall kept at constant temperature. We consider the case when both the vortex ring and the thermal boundary layer generated by the vertical heated wall are stable and laminar prior to any interaction. The impingement process can be divided into two parts. sid A ring-driven stage, where the vortex ring grows in diameter while approaching the wall and therefore it sweeps progressively an increased surface on the wall. siid A boundary layer-driven stage, where the vortex ring moves upward due to the thermal convective motion generated by the heated wall. In some cases, the head-on collision triggers the ring’s azimuthal instability as revealed by the formation of vortical structures arranged on a wavy starlike pattern and confirmed by flow visualizations. A single collision generates important velocity gradients and shear stresses along the wall accompanied with the creation of local vorticity normal to the vertical heated wall. Peak wall shear stresses occur near the point of impact of the vortex ring core.

Simultaneous local jitter, 2-D wavefronts and accelerometer measurements were performed in the flow over a flat-window turret at Mach numbers between 0.3 and 0.4 along a centerplane with a viewing angle varying between 90 and 118 degrees. Both local and global jitter imposed on a small- and large-aperture laser beams were measured using position-sensing devices and a high-speed 2-D wavefront sensor. A linear stochastic estimation technique was applied to separate the mechanically-related component of the jitter from the aero-optical component. Spectra of aero-optical jitter for different elevation angles and speeds were calculated and useful scaling laws were proposed. It was shown that aero-optical jitter was due to the presence of both the stationary and traveling aero-optical components. Detailed analysis of the global and the local jitter spectra and the spectral cross-correlation between them at different speeds and viewing angles is presented and discussed in details. Additionally, PIV system was used to measure the flow field over the flat window, simultaneously with the aero-optical jitter measurements.

Particle image velocimetry (PIV) is utilized with solid carbon dioxide (CO2) seeding material to conduct boundary layer measurements in the test section of the Air Force Research Laboratory’s Trisonic Gas-dynamics Facility (TGF), which has a 24 inch by 24 inch cross-section. Freestream velocity was set at Mach 0.3, Mach 0.5, or Mach 0.8 while stagnation pressure ranged from 500 to 2400 pounds per square foot (psf). High pressure liquid CO2 was directed through expansion nozzles into shroud tubes which led to solidified particles in the wind tunnel stagnation chamber. Two different sets of shroud tubes were used to modify the size of dry ice particles produced and the particle number density. Shroud tubes with an inside diameter (ID) of 0.824 inches provided good particle count and coverage for stagnation pressures between 500 and 1500 psf, while 0.364 inch ID shroud tubes demonstrated good particle count and coverage for stagnation pressures over 1000 psf. Overall, the PIV results produced freestream velocity measurements and boundary layer profiles which compared well with expected values. After initial processing, turbulence data closely followed trends expected within boundary layer, but levels were somewhat higher than anticipated. When the PIV data was processed using elliptical interrogation regions, elongated in the streamwise direction, resulting turbulence levels were much closer to expectations.

The geometry of ductile strain localization phenomena is related to the rheology of the deformed rocks. Both qualitative and quantitative rheological properties of natural rocks have been estimated from finite field structures such as folds and shear zones. We apply physical modelling to investigate the relationship between rheology and the temporal evolution of the width and transversal strain distribution in shear zones, both of which have been used previously as rheological proxies. Geologically relevant materials with well-characterized rheological properties (Newtonian, strain hardening, strain softening, MohreCoulomb) are deformed in a shear box and observed with Particle Imaging Velocimetry (PIV). It is shown that the width and strain distribution histories in model shear zones display characteristic finite responses related to material properties as predicted by previous studies. Application of the results to natural shear zones in the field is discussed. An investigation of the impact of 3D boundary conditions in the experiments demonstrates that quantitative methods for estimating rheology from finite natural structures must take these into account carefully.

Stereoscopic Planar Image Velocimetry (SPIV) has been applied to obtain the three components of the instantaneous velocity vectors on a vertical plane above the burner outlet where the flames propagate. The instantaneous temperature fields have been determined through Laser Induced Rayleigh (LIRay) scattering. Planar Laser Induced Fluorescence (PLIF) on acetone has been used to calculate the average equivalence ratio distributions. Instantaneous turbulent burning velocities have been extracted from SPIV results, while flame curvature and flame thermal thickness values have been calculated using the instantaneous temperature fields. The probability distributions of these quantities have been compared considering the separate influence of equivalence ratio stratification and turbulence. It has been observed that increased levels of turbulence determine higher turbulent burning velocities and flame front wrinkling. Flames characterized by stronger fuel stratification showed higher values in turbulent burning velocities. From the curvature analysis emerged that increased fuel concentration gradients favour flame wrinkling, especially when associated with positive small radius of curvature. This determines an increased surface area available for reaction that promotes a faster propagation of the flame front in the oncoming combustible mixtures.

Over the past twelve years, two-dimensional and stereoscopic particle image velocimetry (PIV) techniques have been used to obtain detailed measurements of the thermal and transport properties of the microparticle component of dusty plasma systems. This letter reports on an extension of these techniques to obtain a volumetric, three-dimensional velocity vector measurement using tomographic PIV. Initial measurements using the tomographic PIV diagnostic are presented.

1.The HARVEST Project 2.2D-2C PIV Measurements 3.NumericalComputation 4.Results 1.ComparisonsPIV / CFD 2.Characterizationof dynamicstall 5.Conclusions ---------------------------------------------------------- Objective:Convertcineticenergyof riversor of tidal flow Specificity:Vertical axis turbine, radial flux, new generationof Darrieusand Gorlovturbine

Particle Image Velocimetry (PIV) denotes a prevailing technique for imaging turbulent fluids with high-speed cameras. Corresponding image sequences provide the basis for estimating such flows and related flow patterns through image processing. While so far this technique has been applied in two dimensions (2D) in terms of an illuminated plane intersecting the volume, recent research focuses on imaging fluids directly in 3D. This paper provides a synopsis of the state-of-the-art and its connections to previous research work on image restoration. We address the basic problems involved and point out promising research directions for reconstructing scalar-valued particle functions from few tomographical measurements. Solutions to these problems will provide an essential processing step prior to the estimation of 3D flows from reconstructed volume functions.

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.

The wakes of wall mounted circular cylinders of very low aspect ratio have been investigated in a wind tunnel. Besides planar PIV, also high resolution tomographic PIV was used to capture the flow phenomena downstream of the cylinder. By changing the velocity U￥ and the cylinder height h at a constant aspect ratio L = h=D, a wide database of different flow conditions was obtained. The resulting relative height of the boundary layer thickness d was 0:6  h=d  2:5, while the Reynolds number based on the length l between leading edge and cylinder centre Rel was 57;000  Rel  188; 000. A pair of counter-rotating vortices was found in the wake of the cylinder. The rotation sense is such, that in the center of the wake a positive vertical velocity component results. Also horseshoe vortices were found next to these trailing vortices. The relative height of the incoming boundary layer has a large impact on the development, strength and dissipation of the vortex system.

A novel technique to increase the accuracy of multiplicative algebraic reconstruction technique (MART) reconstruction from tomographic particle image velocimetry (PIV) recordings at higher seeding density than currently possible is presented. The motion tracking enhancement (MTE) method is based on the combined utilization of images from two or more exposures to enhance the reconstruction of individual intensity fields. The working principle is first introduced qualitatively, and the mathematical background is given that explains how the MART reconstruction can be improved on the basis of an improved first guess object obtained from the combination of non-simultaneous views reduced to the same time instant deforming the 3D objects by an estimate of the particle motion field. The performances of MTE are quantitatively evaluated by numerical simulation of the imaging, reconstruction and image correlation processes. The cases of two or more exposures obtained from time-resolved experiments are considered. The iterative application of MTE appears to significantly improve the reconstruction quality, first by decreasing the intensity of the ghost images and second, by increasing the intensity and the reconstruction precision for the actual particles. Based on computer simulations, the maximum imaged seeding density that can be dealt with is tripled with respect to the MART analysis applied to a single exposure.

Recent years have seen an increasing interest in Micro Air Vehicles (MAVs). MAVs are small (micro sized) aircraft and find their application in a multitude of commercial, industrial and military purposes. To perform their missions MAVs should be small sized, have good manoeuvrability, be well controllable and have a broad flight envelope. When flying in small confinements, the ability to fly at low airspeed and to have good manoeuvrability is critical. One type of MAVs, the flapping-wing MAV, particularly has attractive characteristics for flight in confined spaces. DelFly is a biplane flapping-wing MAV designed and built at Delft University of Technology. DelFly is able to hover and has an onboard camera for observation and vision-based control. For the DelFly project a top-down approach is followed, where from the study of a relative large model experience and theoretical insights can be gained, that can assist to create smaller, functional versions of the DelFly. The ultimate aim of the DelFly project is to improve the design to a very small full autonomous aircraft.

As part of the FARWAKE project, subtask 2.1.1, wake vortex flow experiments are performed using the PIV measurement technique in a water tank. The wake generating model consists of a simple wing/flap model that can be equipped with water jets to simulate propulsion effects. The model was tested at a speed of 3m/s and two angles of attack: 0and 6. Chord Reynolds number of approximately 225.000 and Vortex Reynolds numbers of approximately 150.000 and 220.000 were obtained during the tests. The main objective of the present study is to investigate the influence of a jet on the flap end vortex and the wake vortex formation. The investigation focuses on the direct influence of the jet on the flap end vortex and the (merged) vortex characteristics in the near to mid field. The main vortex characteristics addressed in this report are: the vortex trajectory, the maximum tangential velocity, the peak vorticity and the vortex core radius. The vortex information is obtained from Stereo-PIV experiments performed in a fixed plane perpendicular to the towing direction. The measurements return the 3 components of the velocity in that plane and the streamwise component of the wake vorticity. A submergible moving camera system is used in order to keep the moving vortex in the field of view during the vortex downward motion.

Reducing the deleterious effect of Vortex Induced Vibrations (VIV) in marine risers is an important task for ocean engineers; and many competing factors exist in the design of VIV suppression devices. This thesis explores the experimental minimization of the drag force and the disruption of v0l1ex formation by utilizing VIV suppression devices. Two series of tests are conducted-both utilizing separate testing designs. The first tests are the flexible cylinder experiments, detailed in Chapter 2, which determine the drag force and vibration amplitude of numerous, original testing configurations. The second series of tests are the rigid cylinder, PIV experiments, detailed in Chapter 3. These tests measure both the drag force on the cylinder and the oscillating component of the lift force, the latter of which is a good indication of v011ex formation. The Chapter 3 tests also image the test section wake-providing helpful insight into the physical process of vortex formation. In brief, this thesis presents a detailed description and results of the two series of original VIV suppression tests. Many original configurations are tested, and the results are contained herein.

Turbulent jets have been always present in fluid-mechanic researches due to the large number of applications they have and to the presence of all the turbulence features on them. Thanks to the use of relative new non-intrusive techniques–such as PIV (Particle Image Velocimetry)-, the knowledge of turbulence in general, and turbulent jets in particular has increased. This work is focused on the assessment of both, the main characteristics of the turbulent jet and, at the same time, some significant PIV features. For that aim two experiments are proposed: -The first one, denominated “Spatial Resolution in PIV”, tries to determine the best position to place the digital camera that films the movement of the particles present in the jet, taking into account that we are interested on studying not only the microscales of the turbulent flow, but also the velocity field and the recovering of isotropy by evaluating the turbulent parameters (skewness, kurtosis, square mean derivative ratios,…). -In the second one, called “Effect of the Reynolds Number in Turbulence”, starting from the results of the first experiment, the behavior of the jet depending on the relationship between the inertia forces and the viscous ones is analyzed. To do this, three different zones along the jet and eight different Reynolds numbers are to be studied. This report is structured in four different chapters. The first one corresponds to a theoretical introduction to turbulence. In the second one the experimental setup is described after introducing the PIV measurement technique. The third one presents the results and carries out a deep analysis of them. Finally, in chapter four, the results are summarized obtaining some important conclusions and considering as well future challenges of the present work.

We introduce and test an experimental approach to simulate elastoplastic megathrust earthquake cycles using an analogue model and apply it to study the seismotectonic evolution of subduction zones. The quasi-two-dimensional analogue model features rate- and state-dependent elastic-frictional plastic and viscoelastic material properties and is scaled for gravity, inertia, elasticity, friction, and viscosity. The experiments are monitored with a high-resolution strain analysis tool based on digital image correlation (particle imaging velocimetry, PIV), providing deformation time series comparable to seismologic, geodetic, and geologic observations. In order to separate elastic and nonelastic effects inherent the experimental deformation patterns, we integrate elastic dislocation modeling (EDM) into a hybrid approach: we use the analogue earthquake slip and interseismic locking distribution as EDM dislocation input and forward model the coseismic and interseismic elastic response. The residual, which remains when the EDM prediction is subtracted from the experimental deformation pattern, highlights the accumulation of permanent deformation in the model. The setup generates analogue earthquake sequences with realistic source mechanisms and elastic forearc response and recurrence patterns and reproduces principal earthquake scaling relations. By applying the model to an accretionary-type plate margin, we demonstrate how strain localization at the rupture peripheries may lead to a seismotectonically segmented forearc, including a tectonically stable shelf and coastal high (<20% plate convergence accommodated by internal shortening) overlying the area of large megathrust earthquake slip. Fifty to 75% of plate convergence is accommodated by internal shortening in the slope region where earthquake slip tapers out toward the trench. The inner forearc region remains undeformed and represents a basin.

In the present work the process of a transient fuel injection in a constant high-pressure atmosphere is investigated experimentally. As fuel, dimethyl ether (DME) is used. The goal is to receive new information about the charac-teristics referring to the droplet size, the droplet velocity and the droplet shape in the jet. The high-pressure chamber has a constant pressure of 2 MPa and the fuel spray is injected with a pressure of 6 MPa, 7 MPa and 8 MPa. The spray is analysed by a Shadow-Sizing-technique and digital image analysis with temporal and spatial resolution, which even allows investigating non-spherical droplets. The correlations of d velocity and droplet shape are presented as Joint Probability Density Functions (JPDF). The conclusion of the investigation shows that little increase of the injection pressure has a remarkable effect on the droplet size. Furthermore, the centricity is widely influenced by the injection pressure. With lower injection pressure the droplet velocity decreases. Moreover, the droplets mean diameter shows a significant decrease with increasing time after the injection

Multiphase flows in process industry- project (ProMoni) was a by Tekes and Finnish industry funded three year research project. Five Finnish universities and research units were working in the project in different applications of multiphase flows. All the results are reported in the projects final report1. The aim of this report is to give detailed insight to the work which was made by TUT:s Experimental fluid dynamics group. In the project were developed methods for dispersed phase characterization, for turbulence measurements in multiphase flows and for turbulence characterization. Digital Imaging and Particle Image Velocimetry were the used measurement methods. In institute of Energy and Process Engineering at TUT has been developed Experimental Fluid Mechanics knowledge based on optical and digital imaging measurement methods. The work has been continued several years with support of TEKES and various industrial partners. At this ProMoni-project has been reached a level, which enables research of new key tasks in multiphase fluid mechanics. The project has enabled the research of interaction of dispersed phase and turbulence and this leads to many new inventions industrial applications. This is the main motivation to publish this separate report.

Electrostatic, rotating bell (ESRB) application is one of the most important coating application techniques for industries with demanding specifications for optical attractiveness of coatings, such as automotive. The ESRB process involves production of droplets using a high-speed rotating bell, which are subsequently transported to the substrate being coated via shaping air [1-3]. An electrical potential is applied between the bell and the substrate which further helps droplet atomization and transport. This research investigates the effects of inertia, centrifugal force, drag force, and electrostatic force on the atomization mechanism and particle size distribution using an automotive OEM base coat formulation. Coating flow rate (CFR), shaping air flow rate (SAFR), bell speed (BS), and electrostatic potential (EP) were used as primary parameters to create various atomization conditions and particle size distributions. The atomization mechanism, ligament formation, and particle size distribution were measured using high-speed laser shadowography and image processing. The effects of governing forces and particle size generated on efficiency of droplet transfer to the substrate and optical appearance of the coatings were studied to generate operating windows for optimum process efficiency and appearance.