Planar PIV

Planar PIV measurement of the flow around an oscillating plate

Planar Particle Imaging Velocimetry (PIV) systems allow non-intrusive measurements of two or three velocity components (2C or 3C) in a planar section of gas or liquid flows. The plane (2D) is defined by a light-sheet illuminating seeding particles following the flow. The 2D2C configuration measures the in-plane velocity components whereas the 2D3C system also captures the out-of-plane velocity component.

The flow must contain seeding particles that follow the flow. The laser will fire two light pulses at a small time delay, and the camera records two images of the particles with that small time delay between them. The movement of particles due to the flow is analysed by the software to extract velocity information.

The main system components for this imaging technique are the camera and light source. Based on the image acquisition rate of the system, spanning from 10 Hz to 20 kHz, these systems can be used to acquire ensembles of single-shot images (at 10 – 200 Hz) of a flow field or ensembles of Time Resolved (TR) images (at 0.5 – 20 kHz).

DynamicStudio, our imaging software, guides the user through the entire measurement process from calibration to visualization of results. The guidance includes basic features such as help to focus a camera and advanced post-processing such as pressure from PIV computations, which derives pressure fields from the vector maps.

10 – 200 Hz systems, 2D2C

The simplest system configuration for measuring two velocity components in a plane (2D2C) consists of:

  • Camera  
  • Light source
  • Optics to create a light sheet
  • Synchronizer
  • PC and software for analysis

Stereo PIV, 10 – 200 Hz systems, 2D3C

Stereo PIV is a method for measuring three velocity components in a plane (2D3C) based on the principle of parallax.

By placing two cameras so that they observe the light-sheet plane from two different angles, you obtain slightly different particle images from each camera due to the parallax effect.

The differences between them arise from the third, out-of-plane velocity component and the different observation angles of the two cameras.

After image calibration, this third velocity component can be evaluated. In addition, the two in-plane velocity components can be corrected for parallax errors.

A 2D2C PIV system can be upgraded to a Stereo PIV (2D3C) system by adding:

  • Additional camera
  • Scheimpflug mounts
  • Calibration target
  • Stereo PIV software module

TR-PIV systems for 2D2C and 2D3C, 0.5 – 20 kHz

Both the 2D2C and 2D3C configurations can be upgraded for Time Resolved (high image acquisition rate) measurements. TR-PIV systems relies on the use of high-repetition rate lasers combined with matching high-frame rate cameras. Depending on the application, a TR-PIV system can be a 500 Hz system for measurements in liquids and a >10 kHz system for high speed gas flows.

Components for 2D2C PIV

  • Light source (laser or LED) and light sheet optics
  • Camera
  • DynamicStudio Base Package for easy setup and control of hardware devices, data acquisition, image pre-processing and data storage
  • DynamicStudio 2D PIV add-on for Dynamic Studio: 2D vector field calculation, Least Squares Matching method (LSM) for high accuracy velocity and direct calculation of the velocity gradients, Adaptive PIV with multi-grid cross correlation and average correlation for µPIV. Supports deforming windows and high accuracy calculation, proven by the 2014 PIV challenge. Furthermore, this Add-on includes TR and 2-Frame particle tracking methods to directly and accurately compute particle paths.  Proper Orthogonal Decomposition (POD) allows for investigation of the main spatial modes.
  • For TR PIV, the Oscillating Pattern Decomposition (OPD) add-on allows for investigation of dominant flow structures in the TR data ensemble  
  • Synchronizer for correct timing of laser pulses and camera shutter

Additional components for 2D3C Stereo PIV

  • DynamicStudio StereoPIV software including camera calibration routines that measure and account for perspective distortion arising from the skewed orientation of the cameras, routines to compute the third velocity component from the two camera data sets, and presentation of 3-component velocity information.
  • Calibration targets. Camera calibration requires calibration images to be recorded in the light sheet as well as in front of and behind it. DynamicStudio StereoPIV allows automatic recording of these calibration images.
  • Scheimpflug mounts. The user has to fine-adjust the angle between the CCD (CMOS) array and camera lens in order to focus correctly. To do this, the so-called Scheimpflug condition must be fulfilled. This is achieved by mounting the cameras on Scheimpflug mounts. DynamicStudio StereoPIV includes a focus-assist tool.

Components

Light Sheet Optics

Light Sheet Optics

Modular light sheet optics with fixed or adjustable thickness, ideal for virtually any flow illumination application
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PIV lasers for 10-200 Hz Systems

PIV lasers for 10-200 Hz Systems

Dual cavity, flash-pumped Nd:YAG lasers with extensive range of output energies, designed for PIV applications
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Double Frame Cameras

Double Frame Cameras

High resolution, low noise cameras with double-frame capability for PIV
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TR-PIV lasers for 0.5-20 kHz systems

TR-PIV lasers for 0.5-20 kHz systems

A new generation of dual-cavity, diode pumped Nd:YLF lasers for time-resolved PIV applications
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Time Resolved Cameras

Time Resolved Cameras

High-speed cameras with up to 4 MP resolution and up to 25500 frames per second
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Synchronizers

Synchronizers

Combine cameras, lasers, and an intensifier all with different timing needs into a single system with nanosecond precision
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DynamicStudio

DynamicStudio

State-of-the-art software platform designed to support researchers performing imaging measurements
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PCs and Workstations

PCs and Workstations

PC or Workstation to control your measurement system; store, analyze and post-process the data; and visualize the results
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Seeding Generators

Seeding Generators

Dantec Dynamics offers liquid and powder seeding generators for LDA and PIV, and fog generators for LDA and flow visualization
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Seeding Materials

Seeding Materials

The choice of the right seeding material to scatter the light from laser beams or a light sheet is crucial to the acquisition of successful experimental data
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Light Guiding Arms

Light Guiding Arms

Ideal for flow-field measurements in confined spaces where it is difficult to launch a light sheet and in experiments in which the laser must be separated from the flow rig due to vibration
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Camera Accessories

Camera Accessories

Lenses, filters, Scheimpflug Mounts, fast shutters, DualScope
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Traverse Systems

Traverse Systems

Map fluid velocity in space and perform boundary layer measurements with this high resolution system
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Laser safety

Laser safety

Laser protective eyewear – Eye protection against hazardous laser light is essential for your safety.
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Download Library

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Francisco Felis-Carrasco, David Hess, Bo Beltoft Watz, Miguel Alfonso Mendez

YEAR

2021

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ISPIV
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Laurentiu Moruz, Jens Kitzhofer, David Hess, Mircea Dinulescu

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2019

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ScienceDirect
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Malene H. Vested, F. Gökhan Ergin, Stefan Carstensen, Erik D. Christensen

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2018

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F. Gökhan Ergin, Jimmy Olofsson, Bo B. Watz, Nicolai Fog Gade-Nielsen

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2018

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F. Gökhan Ergin

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2017

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F. Gökhan Ergin, Jimmy Olofsson, Nicolai Fog Gade-Nielsen

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2017

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F. Gökhan Ergin, Dantec Dynamics A/S

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2017

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Hua Wang, F. Gökhan Ergin

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2014

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Per Petersson, Rikard Wellander, Jimmy Olofsson, Henning Carlsson, Christian Carlsson, Bo Beltoft Watz, Nicolas Boetkjaer, Mattias Richter, Marcus Aldén, Laszlo Fuchs, Xue-Song Bai

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2012

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V. Jaunet, J. F. Debiève and P. Dupont

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2012

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Ivana M. Milanovic, Khaled J. Hammad

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2010

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Palle Gjelstrup

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2009

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