Analysis of natural convection in a rhombic enclosure with undulations of the top wall – a numerical study

Abstract

Numerical investigations have been performed in this paper to analyse the natural convection heat transfer, fluid flow and entropy generation aspects for a two-dimensional rhombic enclosure having a wavy top wall of two different number of undulations, heated non-uniformly. The numerical simulations are carried out for three different inclination angle (φ = 30°, 45° and 60°) and for 10³≤ Ra ≤ 10⁶. The results are compared with the enclosure with no undulations at the top wall. We observe that the values of Nu_avg at the top wall are less for undulated top wall as compared to respective values for without undulation. It reveals that higher φ always provide higher Nu_avg from the top wall. Thermal entropy generation (S_θ) is the dominating factor at lower Ra, whereas for higher Ra viscous entropy generation (S_ψ) is dominating for φ = 30°. For φ = 45° and 60°, S_θ is the dominating factor at all Ra.

KEYWORDS:

• Natural convection
• undulation
• rhombic enclosure
• entropy generation

Disclosure statement

No potential conflict of interest was reported by the authors.