Particle Image Velocimetry - Essay Example

a dual camera digital image capturing system which provides appropriate optical access where the two viewing angles accurately fulfil the Scheimpflug condition. [1 – 4] Stereo PIV has widespread applicability in the field of scientific education and research in which motion patterns of particles having a high degree of three dimensional or 3D behaviours are to be examined adopting a mechanistic approach involving velocity vector component analysis. Stereo PIV can be diversely used for analysing the in-cylinder flows of an internal combustion engine [5] or the flow-fields of a gas turbine combustor [6].

Stereo PIV has been useful in analysing fluid flows in thermal turbomachinery [1], artificial hear valves [7], near-wall turbulences [8], fluid-flow patterns around a circular cylinder at high Reynolds Number [9] etc. Stereo PIV is based on the standard two dimensional (2D), two-component (2C) or 2D/2C PIV. Velocity of the flow of a fluid is calculated by standard PIV by defining it as displacement vector of the fluid ∆S over a specified time interval ∆t. The velocity vector V is derived from the cross sections of the target area of the flowing fluid seeded with tracer particles by calculating their positions between two illumination pulses as: Further, Brossard et al explains, “The position of the fluid is imaged through the light scattered by liquid or solid particles illuminated by a laser light sheet.

In most applications, such particles are not naturally present in the flow which, therefore, has to be seeded with tracer particles, assumed to be sufficiently small and light to move with local flow velocity.” [10] After obtaining a series of two illumination pulses, the images are separated into smaller subsections or interrogation areas denoted by IA. These interrogation areas, consisting of the image frames I1 and I2, are then intricately cross-correlated through sub-pixel interpolation.

The vector map of velocity over an entire target area is