Natural convection in a partially heated wavy cavity filled with a nanofluid using Buongiorno's nanofluid model

Purpose: The main purpose of this numerical study is to provide a solution for natural convection in a partially heated, wavy cavity filled with a nanofluid using Buongiorno's nanofluid model. Design/methodology/approach: The domain of interest is a two-dimensional cavity bounded by an isothermal left wavy wall, adiabatic horizontal flat walls and right flat wall with a partial isothermal zone. To study the behaviour of the nanofluid, a two-phase Buongiorno mathematical model with the effects of the Brownian motion and thermophoresis is used. The governing dimensionless partial differential equations with corresponding boundary conditions were numerically solved by the finite difference method of the second-order accuracy using the algebraic transformation of the physical wavy cavity in a computational rectangular domain. The study has been conducted using the following values of the governing parameters: Ra = 10⁴-10⁶, Le = 10, Pr = 6.26, Nr = 0.1, Nb = 0.1, Nt = 0.1, A = 1, κ = 1-3, b = 0.2, h_hs/L = 0.25, h₁/L = 0.0-0.75 and τ= 0-0.25. Findings: It is found that an increase in the undulation number leads to a weak intensification of convective flow and a reduction of Nu because of more essential cooling of the wavy troughs where the temperature gradient decreases. Variations of the heater location show a modification of the fluid flow and heat transfer. The upper position of the heater reflects the minimum heat transfer rate, while the position between the bottom part and the middle section (h1/L = 0.25) characterizes an enhancement of heat transfer. Originality/value: The originality of this work is to analyse the natural convection in a partially heated wavy cavity filled by a nanofluid using Buongiorno's nanofluid model. The results will benefit scientists and engineers to become familiar with the flow behaviour of such nanofluids, and the way to predict the properties of this flow for possibility of using nanofluids in advanced nuclear systems, in industrial sectors including transportation, power generation, chemical sectors, ventilation, air-conditioning, etc.