This work reports on an experimental investigation of turbulent Rayleigh-Bénard convection in a cylindrical cell using tomographic particle image velocimetry (T-PIV). Differently from other anemometric techniques, which allow measurements of two- or three-component velocities only in selected planes of the flow domain [1], T-PIV provides the complete three-dimensional velocity vector field and thus it is suitable for the analysis of turbulent flows exhibiting a complex dynamics [2]. For the present study, a T-PIV apparatus is specifically developed to investigate thermal convection inside a cylinder of aspect ratio 1/2 filled with water at the Prandtl number Pr = 7 and the Rayleigh number Ra = 2E8. The experimental setup is shown in Figure 1. The top cooling system consists of a water heat exchanger coupled with a Peltier module, while the bottom heating system is made of a copper insert heated by a mica-insulated flat heater. Both temperatures are maintained constant by a high-precision thermoelectric controller which performs a PID control based on continual measurements of the copper and cooling water temperatures (stability< 0.01°C). The laser light is shaped into a cylindrical beam that illuminates the entire cell; four cameras record the light scattered by the seeding particles. Flow modes and flow structures are extracted by applying statistical techniques, such as proper orthogonal decomposition.
Tomographic particle image velocimetry of Rayleigh-Bénard convection in a cylindrical sample / Paolillo, Gerardo; Greco, CARLO SALVATORE; Astarita, Tommaso; Cardone, Gennaro. - (2018). (Intervento presentato al convegno International Conference on Rayleigh-Bénard Turbulence tenutosi a Enschede, The Netherlands nel May 14-18, 2018).
Tomographic particle image velocimetry of Rayleigh-Bénard convection in a cylindrical sample
Gerardo Paolillo
;Carlo Salvatore Greco;Tommaso Astarita;Gennaro Cardone
2018
Abstract
This work reports on an experimental investigation of turbulent Rayleigh-Bénard convection in a cylindrical cell using tomographic particle image velocimetry (T-PIV). Differently from other anemometric techniques, which allow measurements of two- or three-component velocities only in selected planes of the flow domain [1], T-PIV provides the complete three-dimensional velocity vector field and thus it is suitable for the analysis of turbulent flows exhibiting a complex dynamics [2]. For the present study, a T-PIV apparatus is specifically developed to investigate thermal convection inside a cylinder of aspect ratio 1/2 filled with water at the Prandtl number Pr = 7 and the Rayleigh number Ra = 2E8. The experimental setup is shown in Figure 1. The top cooling system consists of a water heat exchanger coupled with a Peltier module, while the bottom heating system is made of a copper insert heated by a mica-insulated flat heater. Both temperatures are maintained constant by a high-precision thermoelectric controller which performs a PID control based on continual measurements of the copper and cooling water temperatures (stability< 0.01°C). The laser light is shaped into a cylindrical beam that illuminates the entire cell; four cameras record the light scattered by the seeding particles. Flow modes and flow structures are extracted by applying statistical techniques, such as proper orthogonal decomposition.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.