Raunaq Banga

ED

 5020

  Design

 of

 Surgical

 Devices

Particle

 Image

 Velocimetry

  Submitted

 By:

  Raunaq

 Banga

Introduction

Particle Image Velocimetry (PIV) is a whole-flow-field technique providing instantaneous velocity vector measurements in a cross-section of a flow. Two velocity components are measured, but use of a stereoscopic approach permits all three velocity-components to be recorded, resulting in instantaneous 3D velocity vectors for the whole area. The use of modern digital cameras and dedicated computing hardware, results in real-time velocity maps. It is used to obtain instantaneous velocity measurements and related properties in fluids. The fluid is seeded with tracer particles, which, for sufficiently small particles, are assumed to faithfully follow the flow dynamics (the degree to which the particles faithfully follow the flow is represented by the Stokes number). The fluid with entrained particles is illuminated so that particles are visible. The motion of the seeding particles is used to calculate speed and direction (the velocity field) of the flow being studied.

Figure A: Particle Image Velocimetry

Source: Dantec Dynamics

[2]

Features

• The technique is non-intrusive and measures the velocities of micron-sized particles following the flow. • • Velocity ranges from zero to supersonic. Instantaneous velocity vector maps in a cross-section of the flow. All three components may be obtained with the use of a stereoscopic arrangement. With sequences of velocity vector maps, statistics, spatial correlations and other relevant data are available. Results are similar to computational fluid dynamics, i.e. large eddy simulations, and real-time velocity maps are invaluable tools for fluid dynamics research.

Principles

In PIV, the...