Lagrangian analysis of rotating convection (exp)
Aim: We want to investigate how thermal convection reacts under rotation
Imagine there are two plates and a fluid is confined between these two plates. If we heat up the bottom plate and cool down the top plate, what will happen? Apparently, the fluid close to the bottom plate becomes lighter and the fluid close to the top plate becomes heavier. This density gradient leads to a circulation of the fluid between these two plates. This system is called Rayleigh-Bénard turbulence, see figure 1. This type of thermal convection is quite common in nature and technology. (e.g. atmosphere, ocean currents, the flow at the outer layer of the Sun and a lot of other planets.)
Figure 1:Schematic view of Rayleigh Bénard cell
What if we add rotation to the aforementioned system? There have been some studies on this and they reported that rotation enhances the heat transfer between two plates up to 20%. We want to see (experimentally) what is happening inside the flow field that results in this increase in heat transfer? How the flow parcels velocity and acceleration change for different rotation rates?
The experimental technique is 3D particle tracking velocimetry. In this method, a lot of particles (neutrally buoyant) are added to the fluid. Since these particles are neutrally buoyant, they are supposed to follow the flow field. Four cameras are recording the position of the particles over the time. Then we can find the trajectory of each individual particle. Figure 2 shows a schematic view of the setup.
Figure 2: Schematic view of the experimental setup
Hadi Rajaei, Kim Alards, Rudie Kunnen, Federico Toschi, Herman Clercx
Pranav Joshi (former postdoc)