Investigation Into The Onset Of Turbulent Rayleigh-Benard Convection Using Time-Resolved 2-D Particle Image Velocimetry

2021 ◽  
Author(s):  
Sina Kashanj ◽  
David Nobes
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Time Resolved ◽  
Bénard Convection ◽  
Benard Convection ◽  
Image Velocimetry ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard

scholarly journals Application of simultaneous time-resolved 3-D PTV and Two Colour LIF in Studying Rayleigh-Benard Convection

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Sina Kashanj ◽  
David Nobes
Keyword(s):  
Scanning System ◽  
Flow Topology ◽  
Time Resolved ◽  
Planar Velocity ◽  
Bénard Convection ◽  
Benard Convection ◽  
Out Of Plane ◽  
Cell Measurement ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard

To study the flow topology and temperature distribution of Rayleigh-Benard convection in a highly slender cell, measurement of the simultaneous velocity and temperature in the 3-D domain is required. For this aim, implementing a simultaneous time-resolved 3-D PTV and two-colour PLIF is planned. As a part of this development, for both PTV and two-colour PLIF techniques, the experimental setup has been implemented separately to measure time-resolved 2-D velocity and temperature and is presented in this paper. For PTV, a scanning system is also utilized to scan the flow field to capture the planar velocity in different depths of the flow domain. Progress on calculation of the out-of-plane velocity component including the theory is discussed. Finally, results of the time-resolved 2-D PTV and PLIF systems are presented.

scholarly journals Turbulent transition in Rayleigh-Bénard convection with fluorocarbon (a)

2021 ◽  
Vol 136 (1) ◽  
pp. 10003
Author(s):  
Lucas Méthivier ◽  
Romane Braun ◽  
Francesca Chillà ◽  
Julien Salort
Keyword(s):  
Heat Transfer ◽  
Velocity Field ◽  
Rayleigh Number ◽  
Working Fluid ◽  
Turbulent Transition ◽  
Bénard Convection ◽  
Benard Convection ◽  
Image Velocimetry ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard

Abstract We present measurements of the global heat transfer and the velocity field in two Rayleigh-Bénard cells (aspect ratios 1 and 2). We use Fluorinert FC770 as the working fluid, up to a Rayleigh number . The velocity field is inferred from sequences of shadowgraph pattern using a Correlation Image Velocimetry (CIV) algorithm. Indeed the large number of plumes, and their small characteristic scale, make it possible to use the shadowgraph pattern produced by the thermal plumes in the same manner as particles in Particle Image Velocimetry (PIV). The method is validated in water against PIV, and yields identical wind velocity estimates. The joint heat transfer and velocity measurements allow to compute the scaling of the kinetic dissipation rate which features a transition from a laminar scaling to a turbulent Re 3 scaling. We propose that the turbulent transition in Rayleigh-Bénard convection is controlled by a threshold Péclet number rather than a threshold Rayleigh number, which may explain the apparent discrepancy in the literature regarding the “ultimate” regime of convection.

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