Rayleigh-Bénard-like convection with an asymmetric vertical cooling*

Natural convection is a fundamental phenomenon of high relevance in nature and engineering systems. Here, we experimentally studied Rayleigh-Bénard-like convection conducted in a rectangular tank heated from below and cooled from the top with a cooled sidewall at a Rayleigh number Ra ≈ 1.6 × 10¹⁰. Instantaneous flow fields were characterized at various vertical planes using particle image velocimetry (PIV). We will discuss transient features of the flow motions and characterization of coherent structures using proper orthogonal decomposition POD. In particular, the inspection of the POD coefficients reveals a distinct, coherent convective roll structure along the wider direction of the tank. Complementary temperature distribution, measured using thermochromic particles, illustrates the modulation of the sidewall effects on the temperature fluctuations.