9.3.1. Particle Image Velocimetry (PIV)

Now, if you look at the facilities what you have granted from the Department of Science and Technology come out of India, this facility is known as the particle image velocity materials, so where this is the facility we generate the laser beam, okay so and that laser beam passed through the test sections which has a 2 cameras to monitors how these the laser beams are changing it with an image processing, we can compute the 3 dimensional velocity fields.

Particle Image Velocimetry (PIV) is a major technique used to measure fluid flow velocities. The PIV system involves generating laser beams that illuminate a flow field. The light reflects off particles dispersed in the fluid, and these reflections are captured by two synchronized cameras. By analyzing how the positions of particles change over time, we can compute the velocity fields in three dimensions (x, y, and z). This allows scientists and engineers to visualize how fluids move and interact.

Imagine a large swimming pool with slow-moving water. If you sprinkle glitter throughout the pool and shine a spotlight on the glitter, you can see how the glitter moves with the flow of the water. By taking pictures at different times and analyzing the glitter’s path, you can understand the speed and direction of the water—this is similar to how PIV works.

I am not going more detail how we what is the basic principle of image; particle image velocity materials but there is instrument like a laser beams, then the test sections and the 2 cameras based on that with these principles, what we have given here to monitor the particles at different time frames, we can obtain the 3 dimensional the velocity fields, as you see it is very interesting photographs what we are coming from experimental data.

The data collected through PIV enables researchers to create detailed maps of velocity fields in fluid flows. When the two cameras take images at different time intervals, the software can extract information on how fast and in what direction the fluid is moving between these time frames. This allows for the visualization of complex flow patterns, including rotation and turbulence, which are essential for understanding fluid dynamics in various applications.

Think of it like a traffic camera setup on a busy street. The camera captures images of the cars at different times, and by comparing those images, you can determine how fast each car is moving and in which direction. PIV does the same thing with fluid particles in a flow.

Because here you can get 3 dimensional velocity fields, if you look into that there are 2 vortex are forming just from a pump exit and you can see these factors, you can see the vortex sheddings which is going down and 2 pair of vortex formations are there.

PIV is particularly useful for visualizing vortices, which are swirling motions in fluid flows. By analyzing the velocity fields captured by PIV, one can observe how vortices develop and interact with each other. Vortex shedding, where vortices detach from a surface, can greatly influence fluid properties and behaviors, making its study crucial in fields like aerodynamics and marine engineering.

Imagine stirring a cup of coffee with a spoon. As you stir, you create swirls or vortex formations in the coffee. PIV allows scientists to study these swirls in much detail, understanding how they form and how they affect the movement of the liquid.

So, these very unique facilities that is what we have in a Department of Chemical Engineering IIT, Guwahati, so but what I am to tell it at present, we have the facilities to measure the 3 dimensional the velocity fields with very accurately, so that we can represent like this type of vortex forces what it happens.

The advanced PIV facility at IIT Guwahati allows for precise measurements of fluid dynamics. This capability is essential not only in academic research but also in designing and optimizing various engineering applications, such as automotive aerodynamics, hydraulic systems, and biomedical devices. Accurate understanding of fluid motion is crucial for improving efficiency and performance in these fields.

Consider engineers designing a new sports car. They need to understand how air flows around the car to minimize drag and improve speed. Using PIV, they can visualize air patterns and adjust the design accordingly, much like tweaking a kite's shape to make it fly better in the wind.

--