Numerical analysis of the influence of tilt on natural convection in a double diffusive system within a square cavity containing a thermo-dependent Carreau fluid

¹ Sultan Moulay Slimane University, Polydisciplinary Faculty, Multidisciplinary Research Laboratory in Physics (M.R.L.P), Beni-Mellal, 23000, Morocco
² Rabat National School of Mines (ENSMR), BP: 753 Agdal-Rabat, Morocco
³ Sultan Moulay Slimane University, Faculty of Sciences and Technologies, Industrial Engineering and Surface Engineering Laboratory, B.P. 523, Béni-Mellal, Morocco

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 22 May 2026

Abstract

This study examines the role of tilt in the temperature-dependent, double-diffusive natural convection process occurring in a tilted square cavity filled with a non-Newtonian Carreau fluid. The configuration setup includes impermeable (adiabatic) horizontal walls where no heat or mass transfer is possible, while the vertical walls are maintained at constant temperature and concentration. One of the main objectives of this research is to detail the influence of the cavity tilt angle on the heat and mass transfer rates for different values of the power-law index n and the Pearson number m, which reflects the rheological properties of the fluid. The results obtained, including stream function distributions and Nusselt and Sherwood numbers, indicate that convective transport processes are highly dependent on fluid rheology and cavity tilt angle. It is showed that, for a temperature-dependent viscosity fluid, pseudoplastic fluids strongly favour natural convection compared to Newtonian and dilatant fluids, leading to higher values of |Ψ|max, Nu, and Sh. The cavity inclination is an effective control parameter for heat and mass transfer in double-diffusive natural convection systems involving temperature-dependent non-Newtonian fluids, where it depends strongly on the power-law index rather the thermo-dependent parameter.