Thermal boundary condition studies in large aspect ratio Rayleigh-Bénard convection

We study the influence of thermal boundary conditions on large aspect ratio Rayleigh-Bénard convection by a joint analysis experimental and numerical data sets for Prandtl number Pr=7 Rayleigh numbers Ra=105−106. The spatio-temporal are obtained combined Particle Image Velocimetry Thermometry measurements in cuboid cell filled with water at an Γ=25. In addition, generated Direct Numerical Simulations (DNS) domains Γ=25 Γ=60 subject to different conditions. Our show increased characteristic horizontal extension scale λ̃ flow structures increasing Ra , which due increase convective heat transfer also leads Biot (Bi) cooling plate. However, we find structure size range any case between ones observed idealized captured simulations: On one hand, they larger than applied uniform temperatures plates. other smaller constant flux, latter that grows gradually up domain size. able link this observation qualitatively theoretical predictions onset convection. Furthermore, effect asymmetric transfer. Contrasting reveals probability far-tail events reversed successive decomposition local Nusselt Nuloc traces back sign temperature deviation Θ̃, eventually revealing asymmetries heating plate variance plumes.