Flow Analysis

Examining how two or more substances interact has long been a focus of scientists and their predecessors – the alchemists. We are all familiar with how heavier and lighter substances (such as oil and water) behave when combined but there are many complex situations that require more intensive examination to discover what is taking place. This is especially true in field situations where many factors are at play simultaneously.

There are a number of techniques available to measure flow, both non-visual (such as laser Doppler) and visual. Our focus is on visual methods. There are four general methods in use today. One is particle tracking velocimetry. In this method, the velocities of single particles are observed and measured. This requires a number of cameras to follow the movement of the particles as well as optics and lighting to observe particles at various depth levels.

Another method is scanning PIV (click here for more information on PIV), where thin sheets of the volume are illuminated and scanned to determine velocities of particles within the thin sheet. As many planes are sampled for measurement, longer flow duration is required. The advantage of this method is that imaging at various depths is eliminated, making for simpler camera and lighting set up.

A third method is holographic PIV, where the position of all the particles present at one instant of time is recorded on a holographic plate. An advantage to this method is that millions of velocity vectors can be measured from a high quality hologram. This technique is especially useful for powder processing, and characterizing sprays and aerosol transports.

A fourth method is tomographic PIV. Here, three-dimensional particle distribution within a volume is reconstructed by optical tomography from 2D images taken typically from 4 cameras viewing the same position from 4 different directions simultaneously.  Velocity information is obtained from three-dimensional particle pattern cross-correlation of two reconstructed volumes obtained from subsequent exposures.

In all of these methods, careful consideration of cameras, optics, lighting and recording and analysis solutions is paramount. The optimal solution requires high speed, high resolution cameras, which then necessitates a recording solution that can record high frame rates for long durations accurately, and reliably. It is especially useful that the same recording technology provide analytic capability.

Boulder Imaging Meets Your Flow Analysis Needs

Boulder Imaging has worked with customers to capture and record flow analysis incidents for some very interesting purposes. Two diverse applications were the examination of crayfish behavior changes due to ocean water chemical composition changes as well as the US Navy exploring more optimal ship hull design. In both cases Boulder Imaging high performance digital video recorder (HPDVR) systems were implemented to capture and examine both micro and macro changes in state as well as to isolate and analyze the multitude of variables at play.

When it comes to flow analysis each challenge is unique and Boulder Imaging has a history of helping its customers succeed. We take pride in our unmatched expertise in making the toughest problems evolve into tangible results. If you would like to learn more about Flow Analysis and how Boulder Imaging can assist your organization in addressing particular needs, please contact us by clicking here.

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